Multicomponent structure

Abstract

The present invention generally relates to the field of active packaging, and provides a multicomponent structure configured for releasing one or more volatile compounds in a controlled way. The present invention further relates to a method for preparing the multicomponent structure, and use of the multicomponent structure in different applications, such as preservation, shelf life increase, and deodorisation. The present invention also provides controlled release packaging comprising the multicomponent structure.

Description

[0001] MULTICOMPONENT STRUCTURE

[0002] FIELD OF THE INVENTION

[0003] The present invention generally relates to the field of active packaging and delivery system engineering, and provides a multicomponent structure configured for releasing one or more volatile compounds in a controlled way. The present invention further relates to a method for preparing the multicomponent structure, and use of the multicomponent structure in different applications, such as preservation, shelflife increase, and deodorisation. The present invention also provides controlled release packaging comprising the multicomponent structure.

[0004] BACKGROUND TO THE INVENTION

[0005] Volatile active agents and organic chemicals (VOC) possess beneficial properties to be incorporated in various fields of applications such as antimicrobials, antioxidants, deodorizers and insect repellents, flavoring, preservants, horticulture, and plant growth modifiers. The application of such VOCs is limited due to their limitations including their high volatility leading to their short effectivity period as well the adverse effect upon their burst release to the target headspace and utilization of excess quantities of the volatile compound for extension of efficiency, surpassing the limited dosage of the compound in the headspace composition leading to some unpleasant consequences. In this regard, many VOCs have limited utilization use in real life applications despite their proven effectiveness and benefit. Consequently, it is crucial to control the release of VOCs to the headspace to benefit from their effectiveness without facing the mentioned limitations. Many approaches are conducted to encapsulate and control the release of the VOCs to the environment including but not limited to water / oil emulsion approaches, encapsulation, embedding the VOCs in polymer substrates and triggered release of VOCs from a carrier (Zaitoon et. al, Comprehensive Reviews in Food Science and Food Safety, 2022 (21):541-579). The limitation of using the mentioned systems for VOCs release control can be listed as such: limitation in precise determination of VOCs quantity incorporated to such systems due to loss of VOCs during the processing, difficulties of scaling up the manufacturing process in some systems due to their time and energy consuming nature, as well as their complexity, difficulties on adjusting the system to a new type of VOC, limitations on changing the substrate carrier upon the target applications, limitation on the release controlling duration, dependency on environmental factors for the release triggering, waste management problems due to the resulted wastes upon processing and production which in some cases has adverse effect on environment. In this regard, a system which can surpass the mentioned limitation can be helpful in benefiting the VOCs in a more systematic and controlled manner.

[0006] One of the most important fields that can benefit from such volatile compounds and their controlled release to the environment is active packaging which many volatile compounds can be used in the field such as antimicrobial agents like essential oils and their phenolic parts, sulfur dioxide and chlorin dioxide, ethylene inhibitors such as 1 -methylcyclopropene (1-MCP) and atmosphere neutralizers such as carbon dioxide. In traditional packaging, products are packed in a suitable container and stored as such. However,products that are prone to spoilage, such as food products, cut fruits and vegetables, cut flowers, and the like, only have a limited shelf life in traditional packaging. To improve food safety, extend shelf life, enhance sensory properties, and maintain the quality of the product, active packaging has been developed. Active packaging (AP) is typically defined as a packaging system that actively changes the conditions of the container or package, and mostly involves modifying environmental or physiological conditions within the container. This can for instance be achieved by scavenging or absorption of undesirable compounds such as oxygen, ethylene, flavor / odor, and excessive water. Compounds such as carbon dioxide, antioxidants, and preservatives can for example be added or released into the headspace of the container by using sachets, labels, or films. Active packaging wherein one or more active compounds are released in the package in a controlled manner is also controlled release packaging (CRP).

[0007] Esquivel-Chavez et. al have reported the control of mango decay with Nylon sachets filled with thyme oil / modified starch / agave fructans microcapsules (Esquivel-Chavez et. al, Future Foods, 2021 (3): 100008). A disadvantage of this reported procedure is the lack of control of the quantity of the essential oil (thyme oil) incorporated in the microcapsules.

[0008] It is therefore an object of the present invention to provide an improved multicomponent structure compared to structures known in field of active packaging and delivery system engineering, or at least provide one or more alternative structures.

[0009] SUMMARY OF THE INVENTION

[0010] According to first aspect, the present invention provides a multicomponent structure configured for releasing one or more volatile compounds, comprising at least one outer component and at least one inner component fully enclosed by at least one of said outer component. The inner component comprises at least one porous material, and one or more volatile compounds having an overall vapour pressure from 200 Pa to 200 kPa at 20 °C, at least partially contained within the porous material. The at least one outer component comprises, or consists of, a porous layer of polymer fibres, the porous layer having a thickness from 0.01 to 10 mm, wherein the pores between the fibres form a 3D network of interconnected pores with pore sizes ranging from 0.01 pm2to 20 mm2.

[0011] In an embodiment, the one or more volatile compounds in said multicomponent structure have one or more of the following properties: antimicrobial, antibacterial, antifungal, antimould, deodorant, insect repellant, pesticidal, insecticidal, fungicidal, herbicidal, plants- fruits- and vegetable respiratory inhibitor, reactive oxygen species emitting, flavoring, horticultural effect, plant growth factors, ethylene blockers / inhibitors, CO2 emitters, perfumes, flavors, biogenics, biochemicals, organic and inorganic compounds.In another embodiment, the one or more volatile compounds in said multicomponent structure are selected from the following: essential oils, such as oregano oil, cinnamon oil, lavender oil, clove oil, frankincense oil, peppermint oil, eucalyptus oil, lemongrass oil, orange oil, rosemary oil, bergamot oil, cedarwood oil; active components of essential oils, such as carvacrol, cinnamaldehyde, eugenol, isoeugenol, thymol; ethylene synthesis inhibitors, such as 1 -methylcyclopropene; alcohols, such as ethanol; perfumes; shortchain organic acids, such as butyric acid; aldehydes, such as glutaraldehyde; ketones, such as methyl ether ketone; sulfur containing compounds, such as sulfur dioxide; nitrogen containing compounds, such as nitrous oxide; chlorine containing compounds, such as chlorine dioxide; plant derived volatiles, such as allyl isothiocyanate and methyl anthranilate; secondary metabolites of microbes, such as furanone; and ozone.

[0012] In a further embodiment, the outer component of said multicomponent structure is provided as a porous layer of polymer fibers, wherein the pores between the fibers form an interconnected network.

[0013] In a further embodiment, the polymer fibers in the outer component of said multicomponent structure are formed by electrospinning a polymer material from one or more of the following: polyvinyl alcohol (PVA), polylactic acid (PLA), or polycaprolactone (PCL).

[0014] In another embodiment, the pore sizes between the fibres in the at least one outer component of said multicomponent range from 0.02 to 500 pm2, preferably from 0.03 to 200 pm2, more preferably from 0.04 to 100 pm2, even more preferably from 0.05 to 50 pm2, yet even more preferably from 0.10 to 25 pm2, yet even more preferably from 0.25 to 15 pm2, yet even more preferably from 0.50 to 10 pm2, yet even more preferably from 0.75 to 5 pm2, yet even more preferably from 1 to 4 pm2, yet even more preferably from 2 pm2to 3 pm2.

[0015] In a further embodiment, the thickness of said permeable portion in said multicomponent structure is from 0.025 to 1 mm, preferably from 0.05 to 0.9 mm, more preferably from 0.1 to 0.8 mm, even more preferably from 0.15 to 0.7 mm, yet even more preferably from 0.20 to 0.6 mm, yet even more preferably from 0.25 to 0.5 mm, yet even more preferably from 0.3 to 0.4 mm.

[0016] In another embodiment, the at least one porous material in said multicomponent structure has a loading capacity of the one or more volatile compounds of 10 to 500 wt.%, preferably from 15 to 300 wt.%, more preferably from 20 to 200 wt.%, even more preferably from 25 to 100 wt.%, yet even more preferably from 30 to 75 wt.%, yet even more preferably from 40 to 60 wt.%.

[0017] In another embodiment, the at least one porous material in said multicomponent structure is selected from or more of the following: an inorganic material, such as zeolite, clay, alumina, silica or bentonite; a biopolymer, such as starch, cellulose, amylose, chitosan, alginate, or gums; or a synthetic polymer, such as polyolefin, or polyurethane.In another embodiment, the at least one inner component in said multicomponent structure further comprises one or more diluents, at least partially contained in the at least one porous material, and preferably selected from one or more of the following: water; an alcohol, such as methanol, ethanol, isopropanol; a vegetable oil, such as sunflower oil, olive oil, grapeseed oil, coconut oil; a vegetable oil fraction or derivate, such as fatty acids, fatty acid esters; emulsifiers; C7 and cyclomethicone.

[0018] In another embodiment, the method for preparing said multicomponent structure comprises: impregnating at least one porous material with one or more volatile compounds, thereby providing at least one inner component, and at least partially enclosing the at least one inner component by at least one outer component.

[0019] In a further embodiment, said method comprises the step of mixing the one or more volatile compounds with one or more diluents, thereby providing a mixture, and impregnating the at least one porous material with the mixture, thereby providing the at least one inner component.

[0020] In a further embodiment, said method comprises the step of electrospinning a polymer material, thereby providing the at least one outer component as a layer of polymer fibres, and fully enclosing the at least one inner component with the layer.

[0021] In another embodiment, said multicomponent structure is used for preservation, shelf-life increase, deodorisation, insect repelling or pest control.

[0022] In a further embodiment, the one or more volatile compounds are released from the multicomponent structure for at least 30 days, preferably at least 40 days, more preferably at least 50 days, even more preferably at least 60 days, yet even more preferably at least 70 days.

[0023] In a further embodiment, a controlled release packaging is formed comprising of a container and said multicomponent structure.

[0024] BRIEF DESCRIPTION OF THE DRAWINGS

[0025] With specific reference to the figures, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the different embodiments of the present invention only. They are presented in the cause of providing what is believed to be the most useful and readily description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention. The description provided with the drawings makes apparent to those skilled in the art how the several forms of the invention may be embodied in practice.Figure 1 , abbreviated as FIG. 1 , shows schematically a top view of a multicomponent structure according to an embodiment of the present invention.

[0026] Figure 2, abbreviated as FIG. 2, shows a perspective section of Figure 1 .

[0027] Figures 3-12, abbreviated as FIG. 3-12, show respective sections of variations of outer components. Figure 13-15, abbreviated as FIG. 13-15, show schematically respective top views of variations of multicomponent structures.

[0028] Figure 16, abbreviated as FIG. 16, shows the release profile of oregano essential oil from different inner component materials at room temperature (a) and at fridge temperature of 4°C (b) based on the percentage of the released essential oil according to its initial loaded quantity in the inner component.

[0029] Figure 17, abbreviated as FIG. 17, shows the release profile of oregano and cinnamon essential oil from starch film at room temperature along with their diluted mixture using heptanoin (C7 oil) as diluent. Figure 18, abbreviated as FIG. 18, shows the release profile of oregano essential oil without any barrier, oregano essential oil absorbed in the starch film as the inner component and without the outer component and oregano essential oil used in the multicomponent structure including the starch film as the inner component and PCL based interconnected nanoporous network as the outer component.

[0030] Figure 19, abbreviated as FIG. 19, shows the release profile of oregano and cinnamon essential oil mix diluted with C7 oil from different systems of starch film (inner component), starch film covered with a non-woven commercial textile as the outer component and the outer component comprised of nanoporous network of PCL polymer obtained from electrospinning of 20 wt% PCL solution.

[0031] Figure 20, abbreviated as FIG. 20, shows the release profile of cinnamaldehyde and carvacrol from the multicomponent structures at room temperature using different pore sizes and different thicknesses for the outer component. The release profiles are obtained from the GC-MS analysis.

[0032] Figure 21, abbreviated as FIG. 21, shows the release profile of cinnamaldehyde and carvacrol from the multicomponent structures at fridge temperature (4° C) using different pore sizes and different thicknesses for the outer component. The release profiles are obtained from the GC-MS analysis. Figure 22, abbreviated as FIG. 22, shows the release profile of cinnamaldehyde and carvacrol from the multicomponent structures at room and at two different relative humidity in the environment of release (normal around 40 % and 95%) using PCL for preparation of interconnected nanoporous network as the outer component with the constant pore sizes and at constant thickness of 0.1 mm. The release profiles are obtained from the GC-MS analysis.

[0033] Figure 23, abbreviated as FIG. 23, shows the release profile of cinnamaldehyde and carvacrol from the multicomponent structures both at room temperature (RT) and fridge temperature (4°C) using PCL and PLA for preparation of nanoporous network as the outer component with the same pore sizes and at constant thickness of 0.1 mm. The release profiles are obtained from the GC-MS analysis.

[0034] Figure 24, abbreviated as FIG. 24, shows the raspberries kept in the fridge for 7 days without using the multicomponent structure as preservation method (control) and with multicomponent structure as preservation method with different quantities of essential oils used in the structure.Figure 25, abbreviated as FIG. 25, shows the grapes kept in the fridge for 70 days with (a) and without (b) using the multicomponent structure as the preservation method to control the release of EO in the headspace.

[0035] Figure 26, abbreviated as FIG. 26, shows the plums kept at room temperature for 14 days using the multicomponent structure (a), without preservation method (b), and kept along oregano oil without encapsulation structure (c).

[0036] Figure 27, abbreviated as FIG. 27, shows the release profile of a cinnamon and oregano oil mixture from multicomponent structures using PLA and PCL for preparation of interconnected nanoporous network as the outer component with the constant pore sizes and a constant thickness of 0.1 mm. The release profiles are obtained from weight loss measurements.

[0037] Figure 28, abbreviated as FIG. 28, shows the release profile of 2-phenylethanol (a) and citronellal (b) from multicomponent structures using PLA, PCL and cellulose acetate for preparation of interconnected nanoporous network as the outer component with the constant pore sizes and a constant thickness of 0.1 mm. The release profiles are obtained from weight loss measurements. Figure 29, abbreviated as FIG. 29, shows SEM images of the cross section of nanofibers obtained from 30 wt. / v% of PCL solution (a) and 12 wt. / v% PLA solution (b), and an X-ray microtomography image of the cross section of a perforated 2D PET film (c).

[0038] Figure 30, abbreviated as FIG. 30, shows the results of an in-vitro assessment of using a multicomponent structure against fungal growth using different quantities of oregano and cinnamon essential oil in the structure from 0 (CTRL) to 1 g (100%).

[0039] Figure 31, abbreviated as FIG. 31, shows the strawberries kept at room temperature for 6 days without using the multicomponent structure (a) as preservation method (control) and with multicomponent structure (b) as preservation method.

[0040] DETAILED DESCRIPTION OF THE INVENTION

[0041] The present invention will now be further described. In the following passages, different aspects of the invention are defined in more detail. Each aspect so defined may be combined with any other aspect or aspects unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous.

[0042] As already mentioned herein before, in a first aspect, the present invention provides a multicomponent structure configured for releasing one or more active agent, in particular volatile compounds. The multicomponent structure comprises at least one outer component, and at least one inner component which is at least partially enclosed by the at least one outer component. Preferably, the at least one inner component is fully enclosed by the at least one outer component, which may enhance control of the release of the one or more active agents, in particular volatile compounds, from the multicomponent structure over time.In the context of the current invention, the terms “at least part of” and “at least partially” refer to a definite, non-zero, portion of the item they refer to. The terms “at least part of” and “at least partially” may therefore refer to about 1 %, 2 %, 3 %, 5 %, 10 %, 20 %, 25 %, 30 %, 40 %, 50 %, 60 %, 70 %, 75 %, 80 %, or substantially all, substantially completely, or substantially fully, such as about 90 %, 95 %, 99 %, and even all or fully, i.e. 100 %, of the item they refer to.

[0043] The at least one inner component comprises at least one porous material (also referred to herein as absorptive layer or material), and one or more volatile compounds, wherein the one or more volatile compounds are at least partially contained within the porous material. The inner component is furthermore configured to control the release of the one or more volatile compounds from the at least one porous material over time. Preferably, the one or more volatile compounds are fully contained within the porous material, which may enhance control of the release of the one or more volatile compounds from the at least one porous material over time. In the context of the present invention, the terms “volatile compound” or “volatile compounds” refers to (a) compound(s) which are sufficiently volatile to at least partially become gases at a given temperature, such as at a temperature from -20 to 30°C. Volatility of (a) compound(s) may be expressed as vapor pressure, for instance determined at 20°C. Determination of the vapor pressure at a given temperature is conducted according to the ASTM E1782-22, known in the art. It is an advantage of the multicomponent structure as defined herein, that the release of the active agent can be adjusted for a target application according to the environmental factors including the temperature and humidity, as well as the properties of the volatile compound including the polarity, viscosity and vapor pressure.

[0044] The multicomponent structure as defined herein may comprise one inner component, but it may also comprise two or more inner components, such as two, three, four, five or more inner components. In the context of the present invention, the term “two or more inner components” may refer to two or more different inner components provided as separate units. When the multicomponent structure comprises two or more inner components, preferably all the inner components are at least partially enclosed by the at least one outer component, more preferably fully enclosed, which may enhance control of the release of the one or more volatile compounds from the multicomponent structure over time.

[0045] The at least one inner component as defined herein may comprise only one porous material, but it may also comprise two or more porous materials, such as two, three, four, five or more porous materials. In the context of the present invention, the term “two or more porous materials” may refer to two or more different porous materials provided as separate units, having a different morphology, and / or having a different chemical composition. When the inner component comprises two or more porous materials, they may be comprised in one inner component, but they may also be comprised in two or more inner components, where applicable.The at least one inner component as defined herein may comprise one active agent, in particular a volatile compound, but it may also comprise two or more active agents, in particular volatile compounds, such as two, three, four, five or more active agents, such as volatile compounds. In the context of the present invention, the term “two or more volatile compounds” may refer to two or more different volatile compounds having a different chemical structure. The one or more volatile compounds may be a mixture of volatile compounds, such as an essential oil. The term “essential oil” refers to a plant extract, typically obtained by distillation, and having the characteristic odor of the plant or other source from which it is extracted. When the inner component comprises two or more volatile compounds, the two or more volatile compounds are at least partially contained within the at least one porous material. The two or more volatile compounds may therefore be at least partially contained within one porous material, but they may also be at least partially contained in two or more porous materials, where applicable. Preferably, the two or more volatile compounds are fully contained within the at least one porous material. Preferably, the one or more volatile compounds have a viscosity of 0.1 to 10 000 mP at 20°C, more preferably from 0.5 to 1000 mP, even more preferably from 1.0 to 500 mP, yet even more preferably from 2 to 200 mP, yet even more preferably from 3 to 100 mP, yet even more preferably from 5 to 50 mP, yet even more preferably from 10 to 30 mP.

[0046] The at least one outer component comprises or consists of a permeable portion, wherein the permeable portion comprises a network of interconnected pores with pore sizes ranging from 0.01 pm2to 20 mm2, in particular a three-dimensional (3D) network of interconnected pores. The pore sizes can be determined through SEM imaging in combination with Image J software. The permeable portion may be provided as a layer. Preferably, the permeable portion has a thickness from 0.01 to 10 mm. The thickness may be determined by imaging the cross section of the layer through SEM imaging in combination with Image J software. The permeable portion may have a substantially uniform thickness, but the thickness may also vary in different areas thereof. The at least one outer component is thereby configured to control the release over time of the one or more volatile compounds from the multicomponent structure.

[0047] The multicomponent structure as defined herein may comprise one outer component, but it may also comprise two or more outer components, such as two, three, four, five or more outer components. In the context of the present invention, the term “two or more outer components” may refer to two or more different outer components provided as separate units, having a different morphology, and / or having a different chemical composition. When the multicomponent structure comprises two or more outer components, they may at least partially enclose each other, they may at least partially overlap each other and / or they may be juxtaposed next to each other.

[0048] An advantage of the multicomponent structure as defined herein, is that it allows for prolonged release of the one or more volatile compounds according to the composition of the volatile compound and the specific application in mind. It was found that the multicomponent structure as defined herein may prolong the release of volatile compound for at least 50 % of its release duration at a specific temperature andcompletely exposed to the environment, or the release can be prolonged for at least 100%, at least 200%, at least 300 %, at least 400 %, at least 500 %, at least 600 %, and even at least 700 %, or more. A further advantage of the multicomponent structure as defined herein, is that it allows for controlled release of the one or more volatile compounds over time. This advantage allows for the release of the volatile compound with specific quantities and within specific time intervals at a certain temperature and relative humidity of the environment. Yet a further advantage of the multicomponent structure as defined herein, is that the release of one or more volatile compounds may be tailored to different applications, and different use parameters of the environment wherein the multicomponent structure is used, such as temperature, and relative humidity. Another advantage of the multicomponent structure as defined herein, is that it can be flexible so that a chamber enclosed by the outer component can be compressed e.g. manually, so that release of the one or more volatile compounds can be stimulated.

[0049] An "active agent" as used herein generally refers to a chemical, biological, or other function that helps directly in achieving a desired performance objective. In a particular embodiment, the active agent has sufficient volatility to be present in detectable concentrations (e.g. >1 ppb) in the atmosphere surrounding the multicomponent structure of the invention during (and often after) release of the active agent from the multicomponent structure. Hence, the multicomponent structure of the invention is capable of releasing or controlled-release delivery of a vapor-phase or gas-phase active agent from the inner and outer component as described herein. A "vapor-phase active agent" or "gas-phase active agent" is an active agent that is in the vapor-phase or gas phase, respectively, at the desired conditions (e.g. ambient room temperature (about 23 °C to 25°C), or fridge temperature (about 4°C to 8°C) and atmospheric pressure). Accordingly, the multicomponent structure as defined herein is not limited to (a) particular compound(s), as long as the compounds are sufficiently volatile to at least partially become gases at a given temperature and may be released as gases from the multicomponent structure. Preferably, the one or more volatile compounds have an overall vapor pressure at 20 °C of at least 1 Pa, such as at least 2 Pa, at least 3 Pa, at least 4 Pa, at least 5 Pa, at least 10 Pa. In the context of the present invention, the term “overall vapor pressure” refers to the vapor pressure, determined at 20°C according to ASTM E1782-22, of the one or more volatile compounds comprised in the at least one inner component. When there is only one volatile compound, the overall vapor pressure will be the vapor pressure of said one volatile compound. When there are two or more volatile compounds, such as an essential oil, the overall vapor pressure will be a combination of the vapor pressure of each of the two or more volatile compounds. It was moreover found that compounds with a more particular overall vapor pressure may provide a more controlled release from the multicomponent structure. Preferably, the one or more volatile compounds have an overall vapor pressure at 20 °C of at most 100 kPa, more preferably at most 50 kPa, even more preferably at most 10 kPa, yet even more preferably at most 1000 Pa, yet even more preferably at most 500 Pa, yet even more preferably at most 100 Pa, yet even more preferably at most 50 Pa, yet even more preferably at most 10 Pa. In an embodiment, the present invention provides the multicomponent structure as defined herein, wherein the one or more volatile compounds have an overall vapor pressure from 2000 to 1 Pa, determined at 20°C, preferably from 1000 to 1 Pa, more preferably from 100 to 1 Pa, even more preferablyfrom 10 to 2 Pa, yet even more preferably from 5 to 3 Pa.

[0050] It was furthermore found that volatile compounds with a particular polarity index may provide a more controlled release from the multicomponent structure. Preferably, the one or more volatile compounds have a polarity index from 1 .5 to 10. The polarity index of a volatile compound refers to a measure that indicates the relative polarity of the compound. This index can be determined by liquid chromatography, and is based on the interaction of the compound with the polar stationary phase, in this case, silica, during the chromatography process. A higher polarity index suggests a stronger interaction with the polar stationary phase, resulting in a longer retention time.

[0051] In a particular embodiment, the invention provides a multicomponent structure as defined herein, wherein the one or more active agents, in particular the one or more volatile compounds, have an overall vapor pressure from 200 kPa to 1 Pa at 20°C, a polarity index from 1 .5 to 10, and a viscosity range from 0.1 to 100 cP at 20 °C.

[0052] The one or more volatile compounds may have one or more of the following properties: antimicrobial, antibacterial, antifungal / anti-yeast, antimould, deodorant, insect repellant, pesticidal, insecticidal, fungicidal, herbicidal, plants- fruits- and vegetable respiratory inhibitor, reactive oxygen species emitting, ethylene blockers / inhibitors, CO2 emitters, perfumes, flavors, biogenic, biochemicals, organic and inorganic compounds. The one or more volatile compounds may for instance be selected from essential oils, such as lavender oil, clove oil, frankincense oil, peppermint oil, eucalyptus oil, lemongrass oil, orange oil, rosemary oil, bergamot oil, cedarwood oil, lemon oil, oregano oil, cinnamon oil; active components of essential oils, such as carvacrol, cinnamaldehyde, eugenol, isoeugenol, thymol; ethylene synthesis inhibitors, such as 1 -methylcyclopropene; alcohols, such as ethanol; short-chain organic acids, such as butyric acid; aldehydes, such as glutaraldehyde; ketones, such as methyl ether ketone; sulfur containing compounds, such as sulfur dioxide; nitrogen containing compounds, such as nitrous oxide; chlorine containing compounds, such as chlorine dioxide; plant derived volatiles, such as allyl isothiocyanate and methyl anthranilate; pheromones; secondary metabolites of microbes, such as furanone; ozone; and perfumes.

[0053] In a specific embodiment, the present invention provides the multicomponent structure as defined herein, wherein the active agent is a pheromone.

[0054] The term “pheromone(s)” is a known term in the art, and typically refers to chemical compounds made by animals or insects which are released to trigger specific behavioral or physiological response in another member of the same species.

[0055] The at least one outer component may be provided as a porous layer of polymer fibres, wherein the pores between the fibres form an interconnected network, in particular a 3D network of interconnected pores.The porous layer of polymer fibres can for instance be obtained by electrospinning a polymer material. In an embodiment, the present invention provides the multicomponent structure as defined herein, wherein the at least one outer component is provided as a porous layer of polymer fibres, wherein the pores between the fibres form an interconnected network, in particular a 3D network of interconnected pores.

[0056] In a preferred embodiment, the present invention provides the multicomponent structure as defined herein, wherein the outer component comprises, or consists of, a porous layer of polymer fibres, the porous layer having a thickness from 0.01 to 10 mm, wherein the pores between the fibres form a 3D network of interconnected pores with pore sizes ranging from 0.01 pm2to 20 mm2.

[0057] It was further found that more particular pore sizes may provide improved control of the release of the one or more volatile compounds over time.

[0058] In an embodiment, the present invention provides the multicomponent structure as defined herein, wherein the pore sizes range from 0.02 to 500 pm2, preferably from 0.03 to 200 pm2, more preferably from 0.04 to 100 pm2, even more preferably from 0.05 to 50 pm2, yet even more preferably from 0.10 to 25 pm2, yet even more preferably from 0.25 to 15 pm2, yet even more preferably from 0.50 to 10 pm2, yet even more preferably from 0.75 to 9 pm2, yet even more preferably from 1 to 4 pm2, yet even more preferably from 2 pm2to 3 pm2. In a particular embodiment, the present invention provides the multicomponent structure as defined herein, wherein the pore sizes of the outer component range from 0.01 to 500 pm2, preferably from 0.02 to 100 pm2, more preferably from 0.05 to 9 pm2.

[0059] It is an advantage that the skilled person is able to determine a suitable pore size of the outer component of the multicomponent structure depending on the desired application, the specific volatile compound to be released, and the desired release pattern. The present invention is thus in part based on the realization that a pore size is a relevant parameter for determining the release pattern, and that an optimum pore size can be found for a given application.

[0060] It was also found that a more particular thickness may provide improved control of the release of the one or more volatile compounds over time. In an embodiment, the present invention provides the multicomponent structure as defined herein, wherein the thickness of the permeable portion (including the porous layer of polymer fibres) is from 0.025 to 1 mm, preferably from 0.05 to 0.9 mm, more preferably from 0.1 to 0.8 mm, even more preferably from 0.1 to 0.7 mm, yet even more preferably from 0.20 to 0.6 mm, yet even more preferably from 0.25 to 0.5 mm, yet even more preferably from 0.3 to 0.4 mm. In a particular embodiment, the present invention provides the multicomponent structure as defined herein, wherein the thickness of the permeable portion (including the porous layer of polymer fibres) is from 0.025 to 1 mm, preferably from 0.05 to 0.5 mm, more preferably from 0.1 to 0.4 mm.

[0061] Forming the outer component is not limited to a particular processing technique, as long as a porous layercan be prepared from the polymer or polymer material, wherein the pores form an interconnected network. The processing technique should also provide control of the pore sizes of the porous layer. The outer component can for instance be formed by electrospinning, 3D printing, hydrogel or aerogel formation, blow spinning, self-assembly, phase separation, template synthesis, drawing, centrifugal spinning, foam production, or any combination of two or more thereof. It was however found that electrospinning is particularly suitable to form the outer component, as its time efficient technique which may provide enhanced control of the pore sizes and / or thickness of the porous layer, and consequently may provide improved control of the release of the one or more volatile compounds over time.

[0062] The multicomponent structure as defined herein is not limited to a particular polymer or polymer material to form the porous layer, as long as the porous layer can be prepared from the polymer or polymer material or composite of polymer material in combination with other materials, wherein the pores form an interconnected network. A porous layer of polymer fibres may for instance be prepared from polyolefins, polyesters, polyurethanes, polyvinyl chloride (PVC), polyvinyl alcohol (PVA), or biopolymers. Due do their biodegradability, polyvinyl alcohol (PVA) and polyesters, such as polylactic acid (PLA) and polycaprolactone (PCL), are particularly preferred. In a particular embodiment, the polymer has a molecular weight, in particular a number average molecular weight, from 30kDa to 300 kDa, as determined by GPC, preferably from 50 kDa to 200 kDa, even more preferably from 50 kDa to 150 kDa.

[0063] In a particular embodiment, the present invention provides the multicomponent structure as defined herein, wherein the polymer has a water contact angle (WCA) from 15 to 100 degrees, wherein the WCA is determined on a film of the polymer material.

[0064] In a particular embodiment, the present invention provides the multicomponent structure as defined herein, wherein the at least one outer component is provided as a porous layer of polymer fibres, wherein the pores between the fibres form an interconnected network, and wherein the polymer fibres are formed by electrospinning a polymer material selected from polyvinyl alcohol (PVA), polylactic acid (PLA), or polycaprolactone (PCL).

[0065] The multicomponent structure as defined herein is not limited to a particular porous material comprised in the at least one inner component, as long as the porous material is capable of at least partially absorbing one or more volatile compounds brought into contact with the porous material. The ability for a porous material to absorb and hold one or more volatile compounds in its structure may be referred to as “loading capacity” or “absorption capacity”. To determine the loading capacity, the at least one porous material with a known mass (mpm) is impregnated with the one or more volatile compounds by soaking. After soaking for 1 hour at room temperature, the at least one porous material is isolated, excess volatile compound(s) is wiped from its surface, and its mass is determined (mtot). The loading capacity is determined as the ratio of the amount of volatile compound(s), along with or without diluent(s) or modifier(s), contained in the porous material, relative to the amount of the porous material, according to the following formula:loading capacity = (mtot - mPm) / (mPm)

[0066] The “loading capacity” or “absorption capacity” of a porous material may alternatively, or complementary, be characterized by the porosity of the porous material.

[0067] In an embodiment, the present invention provides the multicomponent structure as defined herein, wherein the at least one porous material has a porosity from 20 to 90 %, preferably from 25 to 75 %, more preferably from 25 to 50 %. Porosity indicates the proportion of the material's volume that is occupied by voids or pores, and it is expressed as a percentage. A higher porosity means more void spaces within the material. The porosity of a material can be determined by measuring both the bulk density and the true density of the material, and calculating the porosity, as will be explained later in more detail.

[0068] It was found that specific materials are particularly suited as porous material, as they may be capable of absorbing and holding larger amounts of the one or more volatile compounds, thus having a higher loading capacity. The at least one porous material can for instance be an inorganic material, such as zeolite, clay, silica, alumina or bentonite. The at least one porous material can also be a biopolymer, such as starch, cellulose, amylose, chitosan, alginate, or gums. The at least one porous material can also be a synthetic polymer, such as polyolefin, or polyurethane. A particular example of a synthetic polymer suitable for use as a porous material is high-density polyethylene (HDPE). In an embodiment, the present invention provides the multicomponent structure as defined herein, wherein the at least one porous material is selected from starch, zeolite, or high-density polyethylene.

[0069] Preferably, the at least one porous material has a loading capacity of the one or more volatile compounds of 10 to 500 wt.%, preferably from 15 to 300 wt.%, more preferably from 20 to 200 wt.%, even more preferably from 25 to 100 wt.%, yet even more preferably from 30 to 75 wt.%, yet even more preferably from 40 to 60 wt.%.

[0070] The at least one inner component may further comprise one or more diluents, wherein the one or more diluents are at least partially contained in the at least one porous material. It was found that the presence of one or more diluents may reduce degradation of the at least one outer component due to contact with the one or more (non-diluted) volatile compounds. Accordingly, a mix of diluent (e.g. oil or water) and volatile compound (e.g. thymol) may be made and included in the porous material. It was moreover found that the presence of one or more diluents may allow to change, e.g. increase or decrease, the release rate of the one or more volatile compounds from the inner component and / or the multicomponent structure. Preferably, the one or more diluents have a viscosity of 0.1 to 10 000 mP at 20°C, more preferably from 0.2 to 1000 mP, even more preferably from 0.3 to 500 mP, yet even more preferably from 0.4 to 200 mP, yet even more preferably from 0.5 to 100 mP. The diluent can be any compound or mixture of compounds which is compatible with the one or more volatile compounds and the at least one porous material, and which is capable of at least partially reducing degradation of the at least one outercomponent. Preferably, the diluent is a liquid compound or mixture of compounds which is at least partially miscible with the one or more volatile compounds. It was found that specific compounds are particularly suited as diluent, as they may provide improved reduction of degradation of the at least one outer component. The one or more diluents can for instance be neutral solvents, such as water or hydrocarbons; an alcohol, such as methanol, ethanol, isopropanol; oil and in particular a vegetable oil, such as sunflower oil, olive oil, grapeseed oil, coconut oil; oil or a vegetable oil fraction or derivate, such as fatty acids, fatty acid esters; emulsifiers; ionic liquids; fluorinated solvents; deep eutectic solvents; hydrocarbons; glycerol; and / or cyclomethicone. In a particular embodiment, the diluent is glycerol triheptanoate oil (C7).

[0071] In an embodiment, the present invention provides the multicomponent structure as defined herein, wherein the at least one inner component further comprises one or more diluents, wherein the amount of the one or more diluents, relative to the total amount of the one or more diluents and the one or more volatile compounds, is from 0 to 90 wt.%, preferably from 10 to 90 wt.%, more preferably from 20 to 90 wt.%.

[0072] In a specific embodiment, the present invention provides the multicomponent structure as defined herein, wherein:

[0073] the at least one outer component is selected from polyvinyl alcohol (PVA), polylactic acid (PLA), polycaprolactone (PCL), and cellulose acetate;

[0074] the at least one outer component is a 3D network of polymer fibers with interconnected pores having pore sizes ranging from 0.01 pm2to 20 mm2and / or has a thickness from 0.01 to 10 mm;

[0075] the at least one inner component is selected from starch, zeolite, and high-density polyethylene; and the one or more active agents, in particular the one or more volatile compounds, is selected from an essential oil or an active component thereof, such as 2-phenylethanol, citronellal, carvacrol, cinnamaldehyde, eugenol, isoeugenol or thymol; or a pheromone; optionally in combination with a diluent such as triheptanoin.

[0076] In a particular embodiment, the porosity of the outer component is at least 60%, preferably at least 70%, more preferably at least 75%, even more preferably at least 80%.

[0077] In a second aspect, the present invention provides a method for preparing the multicomponent structure as defined herein, the method comprising the steps of:

[0078] a) impregnating at least one porous material with one or more volatile compounds, thereby providing at least one inner component; and

[0079] b) at least partially enclosing the at least one inner component by at least one outer component.

[0080] Impregnating the at least one porous material with the one or more volatile compounds may be performed by any method capable of having the at least one porous material at least partially absorb the one or more volatile compounds. Preferably, the at least one porous material is impregnated with the one or more volatile compounds by soaking the at least one porous material in the one or more volatile compounds.More preferably, the at least one porous material is soaked in an excess of the one or more volatile compounds, which may lead to a higher amount of the one or more volatile compounds absorbed in the at least one porous material. The soaking of the at least one porous material in the one or more volatile compounds may be performed for any amount of time in which the at least one porous material can at least partially absorb the one or more volatile compounds. The at least one porous material may for instance be soaked in the one or more volatile compounds for 10 to 120 min at the specific temperature and pressure range in which the volatile compound is in form of liquid (e.g. atmosphere pressure and room temperature for essential oils). After soaking, the at least one porous material may be separated from any excess of the one or more volatile compounds and / or any excess of the one or more volatile compounds on the surface of the at least one porous material may be removed. Any excess of the one or more volatile compounds on the surface of the at least one porous material may for instance be removed by dipping the surface with a paper cloth.

[0081] As mentioned hereinbefore, the at least one inner component may further comprise one or more diluents, wherein similar to the one or more volatile compounds, the one or more diluents are at least partially contained in the at least one porous material. For this purpose, the at least one porous material may be impregnated with the one or more diluents, before the at least one porous material is impregnated with the one or more volatile compounds. It was however found that mixing the one or more volatile compounds with the one or more diluents, and impregnating the at least one porous materials with the mixture, may provide improved control of the amount of volatile compounds and / or diluents absorbed in the at least one porous material. In an embodiment, the present invention provides the method as defined herein, comprising the further step of mixing the one or more volatile compounds with one or more diluents, thereby providing a mixture, and impregnating the at least one porous material with the mixture, thereby providing the at least one inner component.

[0082] In a specific embodiment, the present invention provides a method for preparing the multicomponent structure as defined herein, the method comprising the steps of:

[0083] a1) mixing one or more volatile compounds with one or more diluents, thereby providing a mixture; a2) impregnating at least one porous material with the mixture, thereby providing at least one inner component; and

[0084] b) at least partially enclosing the at least one inner component by at least one outer component. As mentioned hereinbefore, electrospinning a polymer material is particularly suitable to form the at least one outer component, as it may provide enhanced control of the pore sizes and / or thickness of the porous layer, and consequently may provide improved control of the release of the one or more volatile compounds over time. Electrospinning may be performed on a molten polymer material, but it may also be performed on a solution of a polymer material in a solvent. In an embodiment, the present invention provides the method as defined herein, comprising the further step of electrospinning a polymer material, thereby providing the at least one outer component as a layer of polymer fibres, and fully enclosing the inner component with the layer.In a specific embodiment, the present invention provides a method for preparing the multicomponent structure as defined herein, the method comprising the steps of:

[0085] a) impregnating at least one porous material with one or more volatile compounds, thereby providing at least one inner component;

[0086] b1) electrospinning a polymer material, thereby providing the at least one outer component as a layer of polymer fibres; and

[0087] b2) at least partially enclosing the inner component by the at least one outer component.

[0088] In a more specific embodiment, the present invention provides a method for preparing the multicomponent structure as defined herein, the method comprising the steps of:

[0089] a1) mixing one or more volatile compounds with one or more diluents, thereby providing a mixture; a2) impregnating at least one porous material with the mixture, thereby providing at least one inner component;

[0090] b1) electrospinning a polymer material, thereby providing the at least one outer component as a layer of polymer fibres; and

[0091] b2) at least partially enclosing the at least one inner component by the at least one outer component.

[0092] It was found that electrospinning a solution of the polymer material in a solvent may provide enhanced control of the pore sizes and / or thickness of the porous layer. In an embodiment, the present invention provides the method as defined herein, comprising the step of electrospinning a solution of the polymer material in a solvent, wherein polymer material in the solution has a concentration from 1 to 95 wt / v%, preferably from 2 to 75 wt / v%, more preferably from 3 to 50 wt / v%, even more preferably from 4 to 35 wt / v%, yet even more preferably from 5 to 30 wt / v%, yet even more preferably from 10 to 25 wt / v%, yet even more preferably from 15 to 20 wt / v%. In a particular embodiment, the present invention provides the method as defined herein, comprising the step of electrospinning a solution of the polymer material in a solvent, wherein polymer material in the solution has a concentration from 1 to 95 wt / v%, preferably from 2 to 40 wt / v%, even more preferably from 3 to 30 wt / v%. A skilled artisan is capable of determining a suitable solvent (or mixes thereof) based on its ability to dissolve the polymer material, and having the appropriate polarity for the electrospinning process.

[0093] The layer of polymer fibres obtained by electrospinning may be further processed, before it is used to at least partially enclose the inner component. The layer of polymer fibres may for instance be pressed to change its thickness and / or its porosity. Another process to be used is combining stacks of polymer fibres obtained from different polymers / materials and porosities benefiting from the properties of the different used polymers / materials as well wide range of porosities to obtain stepwise and / or selective release of a target volatile compound. Additionally, a logo, name, title, sign,... can be added to the polymer fibres. On the other hand, before electrospinning, a combination of two or more polymers with some additive particles, such as hydrocarbons, ceramics and metals, can be used in the mixture used for electrospinningbenefitting from the properties of the included materials. In an embodiment, the present invention provides the method as defined herein, comprising the further step of processing the layer of polymer fibres before enclosing the at least one inner component with the layer.

[0094] As mentioned hereinbefore, the layer of polymer fibres may for instance be prepared from polyolefins, polyesters, polyurethanes, polyvinyl chloride (PVC), polyvinyl alcohol (PVA), or biopolymers. Due do their biodegradability, polyvinyl alcohol (PVA) and polyesters, such as polylactic acid (PLA) and polycaprolactone (PCL), are particularly preferred. In an embodiment, the present invention provides the method as defined herein, comprising the step of electrospinning a polymer material, wherein the polymer material is selected from polyvinyl alcohol (PVA), polylactic acid (PLA), or polycaprolactone (PCL).

[0095] At least partially enclosing the at least one inner component by the at least one outer component is not limited to a particular configuration, as long as the at least one inner component becomes partially enclosed by the at least one outer component. It was however found that when the at least one outer component is provided as a layer of polymer fibres, it can be enclosed by heat-sealing, taping, glueing, or any other means. Preferably, the at least one inner component becomes fully enclosed by the at least one outer component.

[0096] It was found that the multicomponent structure as defined herein can be used in a range of different applications. The multicomponent structure can for instance be used for the preservation or shelf life increase of products prone to deterioration over time, such as fresh food, processed food, flowers, plants, clothes, textiles, carpets, shoes. The multicomponent structure can also be used for deodorization and / or disinfection of small or large confined spaces, such as cars, closets, fridges, and rooms, such as toilets, bathrooms, bedrooms, and hospital rooms. Depending on the application, the multicomponent structure as defined herein may be used in combination with a container. In such a case, the container is preferably at least partially closed, in order for the one or more volatile compounds to at least partially fill and remain in the headspace of the container. More preferably, the container is closed, in order for the one more volatile compounds to fill and remain in the headspace of the container. Accordingly, the size of the container can be varied and according to its size, the size of the multicomponent structure and its capacity to release the one or more volatile compounds can be adjusted. For example, if the container is a room, then according to the volume of the room, the size of the multicomponent structure and the quantity of the one or more volatile compounds will be larger than when the container has a smaller size.

[0097] In a further aspect, the present invention provides the use of the multicomponent as defined herein, for preservation, shelf life increase, deodorisation, insect repelling and / or pest control.

[0098] As mentioned hereinbefore, it was found that the release of the one or more volatile compounds may extend for long periods of time, such as at least 30 days, such as at least 35 days, at least 40 day, at least 45 days, at least 50 days, at least 55 days, at least 60 days, and even 70 days, or more. In an embodiment,the present invention provides the use as defined herein, wherein the one or more volatile compounds are released from the multicomponent structure for at least 30 days, preferably at least 40 days, more preferably at least 50 days, even more preferably at least 60 days, yet even more preferably at least 70 days.

[0099] In a further aspect, the present invention provides controlled release packaging, comprising:

[0100] a container; and

[0101] the multicomponent structure as defined herein.

[0102] The controlled release packaging as defined herein may include any container suitable for packaging the desired product. Preferably, the container is at least partially closed, in order for the one more volatile compounds to at least partially fill the headspace of the container, while the air flow is prevented and the rapid flow and change of atmosphere is prohibited. More preferably, the container is closed, in order for the one more volatile compounds to fill and remain in the headspace of the container.

[0103] The controlled release packaging as defined herein provides the same advantages as those defined herein for the multicomponent structure.

[0104] In the following, embodiments of the present invention are illustrated with reference to the appended drawings. Throughout the figures, like elements are referred to using like reference numerals.

[0105] In figures 1 and 2, a multicomponent structure 1 is provided with an inner component 10, which is fully enclosed by an outer component 20; the outer component 20 in this case consists of two interconnected layers 21 , 22, which have been sealed together along their peripheral edge 23; in the case shown, both layers 21 , 22 are permeable, so that at least within the peripheral edge volatile compounds can exit the outer component; however, it is also possible that only one of the layers is permeable, or that only a part thereof is; as an example, one or both layers may comprise a permeable portion, such as a window;

[0106] In each of figures 3-12, an outer component of a multicomponent structure, for instance that shown in figures 1 and 2 is shown; For the sake of brevity, only the differences will be described below; in figure 3, an outer component 20 is shown that has single layers 21 , 22; figure 4 on the other hand shows a similar outer component, which however comprises two sublayers 21a, 21b, 22a, 22b in each of the layers 21 , 22, respectively, of the outer component 20; in figure 5, the outer component 20 is formed by only one layer 21 , which is folded back on itself to enclose a space for the inner component; of course in this case, and any other, it is possible that the layer is made up of two or more sublayers as shown in figure 4, having sublayers 21 a, 21b; in figures 5 and 6, the single layer 21 is folded back on itself, however this is not strictly necessary; it is for instance also possible to loop the layer, as shown in figure 7, so that an inside surface is sealed to an outside surface of the same layer 21 along a sealing area 23; the same can be done with multiple layers 21 , 22 (see figure 9), and / or with (a) layer(s) comprising sub-layers 21 a, 21b, 22a, 22b (see figures 8 and 10); To summarize, it is not necessarily important how the outer component20 encloses a space for an inner component 10, but merely that it does; figures 11 and 12 therefore show schematically a such enclosed space, with an outer component 20, regardless of how it has been made to seal the enclosed space;

[0107] The ends of the variation shown in the figures discussed above, can be sealed e.g. as shown in figure 1 .

[0108] As a further example, figures 13-15 show multicomponent structures 20 which have multiple inner components 10; in figure 13 for example, four inner components 10a, 10b, 10c, 10d are present in a single enclosed space, also referred to as a chamber; although each inner component is shown to have the same shape and size in figure 13, this is not necessary; nor is it essential that exactly four inner components are provided;

[0109] As a further example, in figure 14, two chambers are shown which include respectively one and two inner components; in figure 15 on the other hand, two chambers each comprise an inner component of a different size and / or shape;

[0110] The invention is thus not limited to any particular configuration of inner components and chambers, and variations can be made in size, shape, chemical composition, morphology, and number of chambers and inner components.

[0111] EXAMPLES

[0112] Materials and methods

[0113] All chemicals were obtained from commercial sources and used as received, unless stated otherwise.

[0114] Materials for inner component

[0115] Different porous materials were chosen to be analyzed regarding their absorption capacity as well as their release behavior regarding the volatile compounds. These porous materials include zeolite with a pore opening of 3 A (Merck), zeolite with a pore opening of 10 A (Carl Roth), HDPE foam pellets with commercial name of ACCUREL XP200 (Evonik, Germany) and a porous starch film prepared in the lab.

[0116] Preparation of starch film for the inner component

[0117] For the preparation of the starch film, potato starch (Carl Roth) with 10 wt.% was mixed with distilled water at 80° C. After having a gelatinized mixture, ethanol (99 % (Sigma Aldrich)) was added to the mixture while stirring at 800 rpm for 30 minutes. Afterwards, the mixture is kept still to precipitate the formed starch particles followed by removal of the excess ethanol. To obtain the porous film, starch particles were put in a petri dish and dried overnight at room temperature.Volatile Compounds

[0118] In this study, the used volatile compounds are cinnamon oil (Carl Roth), oregano oil (Carl Roth), 2-phenylethanol (laboratoriumdiscounter) and citronellal (laboratoriumdiscounter), and the diluent used is triheptanoin (Stearinerie Du Bois, France). Equal weight of cinnamon and oregano oil are first mixed and then diluted with triheptanoin with final concentration of 35 wt.%.

[0119] Materials for outer component

[0120] Polyvinyl alcohol (PVA), polycaprolactone (PCL), polylactic acid (PLA) and cellulose acetate (CA) are used to fabricate the outer component. The specifications of these materials are presented in Table 1.

[0121] Preparation of the outer component through electrospinning

[0122] Table 1 presents the utilized solution formulations for the fabrication of the outer component by means of electrospinning. After the preparation of these solutions, the electrospinning process is carried out using a bottom-up customized Nanospinner 24 (Inovenso) electrospinning machine operated at room temperature. The polymer solutions are loaded in a standard syringe and pumped by means of a syringe pump (PSNE500, ProSense) at a controlled flow rate in the range of 0.05 mL / h to 1 mL / h through a polyethylene tube ending in a brass nozzle possessing an inner diameter of 0.8 mm. The nozzle, connected to a DC high voltage source, is positioned vertically under a grounded stainless steel rotating collector drum. The distance between the brass nozzle and the collector is adjusted in a range between 20 - 10 cm while the collector is rotating at a speed of 100 - 300 rpm. By applying a high voltage in a range of 15 - 30 kV, a Taylor cone forms by the electrification of the liquid droplet at the nozzle, which leads to stretching of the charged polymer jet, followed by collection of nanofibers onto the rotating collector. The nanoporous network is prepared by collecting the formed nanofibers on aluminum foils attached to the collector.

[0123] It should be noted that, after the PVA solution is prepared, 0.5 wt.% of citric acid, regarding the weight of water, is added to the solution with the aim of crosslinking the nanoporous network in the oven at temperature of 150° C for 1 hour.

[0124] Table 1 : Used polymers, the polymer-solution concentration ranges and the solvents used for preparing the polymeric solution.

[0125]

[0126]

[0127] The cross-sectional morphology of these materials is analyzed by means of Scanning Electron Microscopy (SEM). Their absorption capacity is determined as previously explained. The release profile of the materials as inner components is examined via weight-loss rate determination. Dilution of the volatile component to adjust its physicochemical properties is also examined.

[0128] Scanning electron microscopy (SEM)

[0129] To analyze the pore structure and / or morphology of the investigated components, an scanning electron microscopy (SEM) imaging device (JSM-6010 PLUS / LV, JEOL) is used. SEM images are captured with an accelerating voltage of 7 kV, a filament temperature of 160°C, and an electron beam intensity of approximately 95 pA at a working distance of 10 mm. Prior to imaging, the samples are coated with a thin layer of gold using a sputter coater (JFC-1300 autofine coater, JEOL) to prevent charge accumulation. After obtaining the images, Image J software is used to measure the opening of the pores in each material.

[0130] Porositv determination

[0131] To calculate the porosity of the different materials with different structures and morphologies used in this study, the weight of a specific volume of the materials are first measured which is the bulk density of the material with its specific structure and morphology. Then, the porosity is calculated according to the true density of the used material according to the following formula where P is porosity, pbuikis the bulk density and ptrueis the true density of the material:

[0132]

[0133] Preparation of the multicomponent structure

[0134] For the preparation of the multicomponent structure, the impregnated porous materials are placed in between at least two layers of nanoporous network with different pore sizes, and sealed by heat, tape or glue. Afterwards and optionally, the multicomponent structure can be incorporated or placed in between a porous bag / container consisting of nonwoven textile or paper as a holder of the multicomponent structure, to give a specific shape to the structure, to have a specific naming / branding on the structure, to adjusting the aesthetic properties of the structure or to have (safety) signs on the structure.

[0135] Release measurement through weight loss method

[0136] To measure the released quantity of the volatile from the porous absorptive layer (inner component) withor without the aforementioned bag / container as well as the release of the volatile from the multicomponent structure with or without the aforementioned bag / container, the initial weight of the absorbed volatile along with the porous absorptive layer with or without the aforementioned bag / container or the multicomponent structure with or without the aforementioned bag / container (the systems) are measured using a high precision scale with a precision of 0.0001 g. Then, the systems are placed in a container at a controlled temperature. Afterwards, through specific time intervals the weight of either the porous absorptive layer with or without the aforementioned bag / container or the multicomponent structure with or without the aforementioned bag / container (the system) is measured using the high precision scale and the remained quantity of the volatile compound is calculated by deduction of the weight of the system without the volatile compounds from the weight of the system at each time interval of the release. The release percentage, R, of the volatile compounds from each of the mentioned systems and at each time intervals are then calculated based on the initial quantity of the absorbed volatile compound in the porous absorptive layer using the following formula where Wi is the initial quantity of absorbed volatile compounds and Wt is the remained quantity of the volatile compounds in the system at each time interval:

[0137] Wi - Wt

[0138] R (%) = x 100

[0139] Wi

[0140] Release measurements using GC-MS headspace method

[0141] The multicomponent structures, containing the volatile components and their diluents absorbed by the absorptive porous inner component along with the outer component comprising nanoporous networks of different polymers as well as different pore sizes and thicknesses, were placed into 20 mL vials, ensuring a headspace volume of approximately two-thirds of the vial capacity. The vials were sealed with PTFE-lined septa to prevent contamination or escape of volatiles. To allow equilibration of volatile compounds between the sample and the headspace, the vials were incubated in an incubator set at both room and fridge (4 °C) temperature for specific time intervals. Afterwards, an automated headspace sampler (G188A Headspace sampler -Agilent Technologies, Palo Alto, USA) was used to extract 1 mL of headspace gas for injection into the GC-MS at each time interval between 1 and 70 days. After the extraction of the headspace sample, the vials were opened and flushed with nitrogen gas for one minute to ensure the headspace is emptied from the volatile compounds for the next sample extraction. Then the analysis was performed on an Agilent 6890N gas chromatograph coupled to an Agilent 5973N mass selective detector while Agilent MSD ChemStation data acquisition and data handling software were used for automation of the process. The different substances of the volatile components were separated on a VF-624 capillary column (60 m x 0.32 mm (i.d.); 1.8 pm film thickness) (Varian, Walnut Creek, USA). High-purity helium (Alphagaz™ 2, Air-Liquide) was used as carrier gas at a flow rate of 12.4 mL min-1. The mass spectrometer was operated in the selected ion monitoring (SIM) mode recording the mlz values of 131 and 135 related to cinnamaldehyde and carvacrol respectively. The retention times were 34.5 min for cinnamaldehyde and 35.5 min for carvacrol. For quantification, peak area ratios of the analytes to the internal standard were calculated as a function of the concentration of the substances. Calibration curves were prepared by analyzing standard solutions of the cinnamaldehyde and carvacrol at knownconcentrations under identical conditions present in the headspace of the vials. The peak areas were plotted against analyte concentrations to establish linear regression curves. For samples, analyte concentrations were determined by comparing their peak areas to the calibration curves. The quantity of the released volatiles to the headspace are then measured based on the initial quantity present in the multilayered structure based on their weight or volume.

[0142] To assess the effect of relative humidity on the released profile of the volatiles from the multicomponent structure, larger vials were used with the volume of 100 ml and the relative humidity of the headspace in the vials were kept at 95 %. The composition of the headspace of each vial was then measured using the method mentioned above.

[0143] In-vitro assessment of the effectiveness of using the multicomponent structure in preventing or inhibiting fungal growth

[0144] The effectiveness of the multicomponent structure in inhibition of Penicillium, Aspergillus Niger and Cladosporium fungi was determined via film-diffusion method. The multicomponent structure with the size of 0.5 x 0.5 cm was placed in the petri dishes containing Mueller-Hinton agar, inoculated with 0.1 ml suspension of each fungus. For the control treatment, the multicomponent structure with the same size and without any essential oil was placed in the petri dishes. The plates were sealed and incubated for 14 days. The activity of the multicomponent structures were then evaluated by the inhibition-halo diameter around them. It should be noted that, different quantities of oregano essential oil, from zero as the control to 1 g with the difference of 0.1 g in each of the samples, was used in the multicomponent structure to assess the minimum inhibitory concentration to be used in such structures.

[0145] In-vivo assessment of the effectiveness of using the multicomponent structure in preserving raspberries In-vivo experiments were conducted to evaluate the effectiveness of a multicomponent structure for preserving raspberries at refrigerator temperature. The effectiveness of the multicomponent structure on raspberries preservation was tested at three different concentration levels of 0.4, 0.8 and 1.2 g of cinnamon and oregano oil in each of the structures. Fresh raspberries were sourced directly from farmers without any post-harvest modifications. For each concentration level, five test samples were prepared, alongside five control samples. Each set of samples for each concentration level was placed in a larger container to prevent cross-contamination between different concentrations. The raspberries were packaged in smaller containers with the dimension of 13 cm x 10.5 cm x 3.5 cm. The smaller containers were disinfected and thoroughly dried before use. The smaller containers are commercially available packages offered for the packing of raspberries which have perforations, as well. The larger containers holding the smaller containers with raspberries as well as the smaller containers were opened twice daily for inspection of the raspberries for signs of mold, fungi, or bacterial infections. This procedure also helped to reduce excessive moisture accumulation inside the containers.

[0146] In-vivo assessment of the effectiveness of using the multicomponent structure in preserving grapes In-vivo experiments were conducted to evaluate the effectiveness of the multicomponent structure forpreserving table grapes at refrigerator temperature. The effectiveness of the multicomponent structure on grapes preservation was tested at a single concentration level of 1g of oregano oil in the multicomponent structure. Fresh grapes were sourced directly from farmers without any post-harvest modifications. The grapes were packaged in closed and sealed containers with the dimension of 20 cm x 10 cm x 10 cm without any holes. The containers were disinfected and thoroughly dried before use. The containers with the control sample without the multicomponent structure and the test sample using the multicomponent structure alongside with the grapes were put in the fridge and inspected daily to observe the signs of molds and fungi for a prolonged duration of time.

[0147] In-vivo assessment of the effectiveness of using the multicomponent structure in preserving yellow plums To demonstrate the effectiveness of the multicomponent structure in extending the release pattern and prolonged preservation of the food, in-vivo experiments were conducted at room condition in three scenarios:

[0148] 1. Yellow plum without preservation,

[0149] 2. Yellow plum in presence of oregano essential oil,

[0150] 3. Yellow plum in presence of the multi component structure impregnated with oregano essential oil. In scenarios 2 and 3, 1 g of oregano essential oil is used and at different intervals up to 14 days the quality both visually and also in terms of the fruits firmness were examined. In each case, the plums were placed in a capped container with similar size and similar filled volume of the fruits. The plums were obtained from directly from an organic farm without any further modifications. The containers were commercially available 1 .5 liter polypropylene thermoformed boxes, which were sanitized in boiling water. The containers in all three scenarios were inspected daily to observe the signs of molds and fungi and / or loss of fruit firmness.

[0151] In-vivo assessment of the effectiveness of using the multicomponent structure in preserving eclairs In-vivo experiments were conducted to evaluate the effectiveness of the multicomponent structure for preserving eclairs at refrigerator temperature. The effectiveness of the multicomponent structure on eclairs preservation was tested at a single concentration level of 0.5g of citronellal in the multicomponent structure. Fresh eclairs were sourced directly from producer’s company without any modifications and kept in the original packaging with the dimension of 20 cm x 10 cm x 4 cm with the total weight of eclair in each package to be 190 g. For the experiment 3 sets of packages contained the multicomponent structure for the preservation study and 3 packs were kept as original without any modification. All the packs were stored in fridge at temperature of 7 °C and inspected daily to observe the changes in the structure and color for a prolonged duration of time.

[0152] In-vivo assessment of the effectiveness of using the multicomponent structure in preserving par-baked bread

[0153] In-vivo experiments were conducted to evaluate the effectiveness of the multicomponent structure forpreserving par-baked breads which contained butter at room temperature. The effectiveness of the multicomponent structure on breads preservation was tested at a single concentration level of 0.5g of 2-phenylethanol in the multicomponent structure. Store bought Par-baked breads without any modifications were kept in two sets on plastic containers with dimension of 10 cm x 10 cm x 10 cm in which one set of the containers contained the multicomponent structure and the other set kept unmodified as the control samples. For each of the conditions, 3 packages were prepared and inspected daily to observe the changes in the structure and microbial growth for a prolonged duration of time.

[0154] In-vivo assessment of the effectiveness of using the multicomponent structure in preserving beef meat In-vivo experiments were conducted to evaluate the effectiveness of the multicomponent structure for preserving beef meat stocks in the fridge at 7° C. The effectiveness of the multicomponent structure on beef meat preservation was tested at a single concentration level of 0.5g of 2-phenylethanol in the multicomponent structure. Store bought par-baked breads without any modifications were kept in two sets on plastic containers with dimension of 10 cm x 10 cm x 10 cm in which one set of the containers contained the multicomponent structure and the other set kept unmodified as the control samples. For each of the conditions, 2 packages were prepared and inspected daily to observe the changes in the smell, structure and color change for a prolonged duration of time.

[0155] In-vivo assessment of the effectiveness of using the multicomponent structure in preserving strawberries In-vivo experiments were conducted to evaluate the effectiveness of the multicomponent structure for preserving strawberries at room temperature. The effectiveness of the multicomponent structure on preservation of strawberries was tested at a single concentration level of 0.5 g of 2-phenylethanol in the multicomponent structure. Store bought strawberries without any modifications were kept in two sets on plastic containers with dimension of 10 cm x 10 cm x 10 cm in which one set of the containers contained the multicomponent structure and the other set kept unmodified as the control samples. It should be noted that in this set of the experiment, the lid of the containers were kept open to be able to assess the effectiveness of the multicomponent structure in open packaging condition. Also, the two conditions were kept separate from each other to prevent the interference of the volatile release on the control samples. For each of the conditions, 2 packages were prepared and inspected daily to observe the changes in the structure and microbial growth for a prolonged duration of time.

[0156] Results

[0157] Structure of the inner component materials

[0158] The investigation of the structure of the materials for the inner component reveals their distinct characteristics. In order to investigate the structural characteristics of each material, their morphology is imaged from their cross section which in the case of HDPE foam, the foams granule is cut in the middle, in case of the starch film, the film is cut diagonally from edge and in case of the zeolite beads, they are pressed to break the beads and have their cross sectional view. The cross-sectional morphology of each of the selected inner components to be studied are obtained from SEM imaging. The results show thatHDPE Foam has large pore openings of between 50-250 pm while starch film has a more uniform texture with finer pores with a distribution of pore openings between 10-50 pm. It should be noted that zeolites are in form of beads, with dimensions slightly smaller than HDPE foam granules, in which the cross section of the zeolite beads are showing a very fine particles of zeolite adhered to each other to form the porous structures with very small pore openings in the range of 10 to 3 A as reported in their specifications. It should be noted that the porosity of the HDPE foam is 75 % while the porosity of the starch film is in the range of 27%.

[0159] Table 2: Porosity of the used materials for the inner component.

[0160] Material Porosity Source

[0161] HDPE Foam 75% Product details Evonik ACCUREL XP200

[0162] Starch Film 27% Internal calculations according to the M&M

[0163] Zeolite 10 64% De Gennaro et al., Materials 2022, 15, 5574

[0164] Zeolite3 27 % Lin, R., et al., Industrial & Engineering Chemistry Research, 2014,

[0165] 53(41), 16015-16024.

[0166] Absorption capacity of the inner component materials

[0167] The loading capacity of different materials for inner component are examined by loading them with oregano essential oil as the volatile component and weighing the material before and after the loading. The results are reported in

[0168] Material Loading capacity (wt%)

[0169] Starch film 36 ± 1

[0170] HDPE Foam 295 ± 59

[0171]

[0172] Zeolite 10 A 52 ± 2

[0173] . It should be noted that for the determination of the loading capacities, equal weight of each of the mentioned materials are used in the loading process. According to this table, HDPE Foam absorbs oregano essential oil as high as 300 wt.% of its weight while for the rest of the materials this quantity is in the range of 30 to 50 wt.%. Superior loading capacity of HDPE foam is due to its high porosity and the presence of large interconnected pores and the fact that HDPE Foam exhibits a higher pore volume at a fixed weight considering lower density of HDPE.

[0174] Table 3: The loading capacity of different inner component materials.

[0175] Material Loading capacity (wt%)

[0176] Starch film 36 ± 1

[0177] HDPE Foam 295 ± 59

[0178] Zeolite 3 A 30 ± 1

[0179]

[0180] Release profile from the inner component materials

[0181] The release profile of oregano essential oil from the different inner component materials at room temperature and at fridge temperature of 4°C is shown in Figure 16. These release profiles are obtained via weight loss analysis of the loaded inner component materials with oregano essential oil. According to Figure 16a related to the release at room temperature, in the initial stages of the release, inner components based on Zeolite (3 A and 10 A) are still absorbing substances from the environment (mainly moisture) to reach their saturation point and they do not show any release. This is due to selective absorptions of compounds with Zeolite as intergranular and intragranular porosities with different dimension scales are present. However, the release starts from day 1 for Starch film and HDPE foam. The delay in the release of the absorbed volatile and / or the long duration for the absorption process of the Zeolite are not favorable parameters, taking the practicalities regarding the innovation into account, namely the material handling time, and the fact that for certain applications, immediate intervention of the active component into the environment are essential.

[0182] On the other hand, although the absorption capacity of the HDPE foam is higher than that of the starch film and the zeolites, only 20 % of the absorbed essential oil is released over the 30 days duration of the analysis. Additionally, Starch film exhibits a more linear profile compared to that of HDPE Foam which indicates a gentle consistent release of active material. However, despite Starch film and zeolites, HDPE Foam exhibits an initial burst release. This observation also indicates that for the intended application, starch film is a better option, next to the fact that it is obtained from natural sources, it can be produced at different scales, and it is finely customizable to the needs of the innovation.

[0183] The same trends can also be seen in the release profile of the oregano essential oil from these inner component materials at fridge temperature (4 °C) as is shown in Figure 16b. Based on this figure, zeolite inner materials with two pore sizes, first absorb the substances from the environment and only after several days they start to release the essential oil. It should be noted that the duration of absorbing the moisture from the environment at 4 °C is longer than the room temperature, which is due to the higher humidity at lower temperatures and the fact that this low temperature delays the flow of the substances due to reduced diffusion. This also explains the fac that overall release from all the inner components are lower at 4 °C compared with the ones from the room temperature.

[0184] In conclusion, HDPE foam can absorb more essential oil or volatile component than the other inner component materials, but the overall released quantity is low proportional to the initial absorbed quantity. The same applies to Zeolite materials. . Starch proves to be a suitable material in gently releasing the active material with minimal residual in its structure.

[0185] The release profile from Starch Film and the effects of oil mix modification with glycerol triheptanoate Essential oils such as oregano and cinnamon are blends of various chemical compounds. Oregano essential oil primarily contains compounds such as carvacrol, which is phenolic monoterpenes. The oilalso includes other components like sesquiterpenes, each contributing to the unique properties and biological activities of the oil. On the other hand, cinnamon essential oil is rich in cinnamaldehyde, an aromatic aldehyde with a benzene ring attached to a propenyl group and an aldehyde functional group. The oil also contains other compounds like eugenol and linalool, which add to its therapeutic properties. These diverse compounds in essential oils interact synergistically, enhancing their overall effectiveness and making them valuable in various applications, from aromatherapy to antimicrobial treatments. One of the approaches to finetune the effectiveness of the essential oils is their blending.

[0186] Each of these compounds has different volatility, which contributes to the overall volatility of the essential oil. When comparing the volatility of oregano and cinnamon essential oils, oregano essential oil tends to be more volatile. This is primarily due to its higher content of monoterpenes, which are lighter and have lower boiling points compared to the main components of cinnamon essential oil. cinnamon essential oil, on the other hand, contains a significant amount of cinnamaldehyde, which has a higher boiling point and is less volatile. However, based on the ration of these different compounds, the essential oils can have similar or different overall volatilities.

[0187] One of the main approaches to modify the absorption of the active agents and their release profile through the inner component is the blending of the active agent with the modifiers as diluents. The modifiers can affect the release based on different aspects:

[0188] - changing the viscosity of the final mix which can reduce or increase the absorbability in the inner component as well as the fluidity of the volatile material and its release rate, or

[0189] - changing the affinity of the modifier towards the inner component as well as the volatile component, which alters both absorbability and release rate.

[0190] The combination of higher affinity of the modifier to the volatile component and the lower affinity of the modifier to the inner component can lead to decreased of the release rate while by increasing the affinity of the modifier to the inner component and decreasing it towards the volatile component the release rate can increase.

[0191] Figure 17 shows the release rate of two essential oils from starch film as the inner component while the essential oils are used alone, modified with glycerol triheptanoate oil (C7 oil) or mixed and modified with C7 oil. Glycerol triheptanoate oil is a triglyceride with three fatty acids each containing 7 carbon atoms and is often used as a wetting agent or as tracing markers in different products. In this research it is added at a rate of 65 wt.% to the essential oils. The release profile data (Figure 17) is obtained through measuring the weight loss through time. C7 oil is chosen as it is a food ingredient and do not impose adverse health and safety risks. The release profile of the oregano and cinnamon essential oil are similar showing approximately the same range of volatility according to the vapor pressure of their main components (Carvacrol and Cinnamaldehyde respectively) reported in Table 4. After mixing with C7 oil, the release rate for each of the essential oils are increased as C7 decreases the viscosity of the mix due to its lower viscosity compared to the main components of the essential oils (Table 4). On the other hand, the hydrocarbon chain of the C7 oil has high affinity toward the starch film which also leads to the increased in the release rate of the essential oils from the starch film. This can be attributed to the presence of linear amylose in the starch structure which form helical structures with hydrophobic cavities which are prone toinclude the hydrophobic compounds (such as fatty acids or triglycerids). In our study, the cavity of starch is filled with the C7 oil which leads to easier release of the volatile parts of the essential oils to the headspace.

[0192] Table 4: The viscosity and vapor pressure of Carvacrol, Cinnamaldehyde and glycerol triheptanoate.

[0193] Compound Viscosity at 20 °C mPa.s Vapor pressure at 20 °C Pa

[0194] Carvacrol 28.5 3.1

[0195] Cinnamaldehyde 22.1 3.8

[0196] Glycerol 14.5

[0197] triheptanoate

[0198] As explained earlier, cinnamon essential oil contains a high concentration of cinnamaldehyde, which is more soluble in oils compared to the primary components of oregano essential oil, such as carvacrol and thymol. This higher solubility leads to improved overall volatility of cinnamon essential oil as the volatility of its major compound is improved by being solved in C7 oil.

[0199] Fabrication and structure of the outer component

[0200] For the manufacturing of the outer components, four different materials at different concentrations are used. The processability via electrospinning is determined, and the structure of the resulting mats is characterized through SEM analysis. Then, for a selected mat / layer structure, the impact of the outer component on the release profile is studied. Additionally, the influences of outer components structural parameters, such as pore size and mat thickness, as well as environmental variables such as temperature and humidity, on the release profile are investigated. By altering the choice of the material to fabricate the outer component, the impact of polymer’s polarity on the release profile is captured.

[0201] The results show an evolution in the pore sizes of the pore networks through changes in the type of polymers and the polymer solution concentration. According to Table 5, increasing the polymer solution concentration for each polymer type results in larger pore sizes while the porosity declines. This is due to the fact that by increasing the concentration, the viscosity of the solution decreases and at similar processing conditions, thicker fibers and larger pore sizes will be obtained. Additionally, altering the polymer type (and eventually the viscosity of the solution) allows for further adjustment of the range of pore sizes and porosities to meet specific applications and requirements. Achieving the same range of pore sizes and porosity with two different polymer types depends on their solution concentrations and the molecular weight range of the polymers used. In this study, adjusting the solution concentration for PCL to 30% wt / v and for PLA to 12% wt / v, along with the reported molecular weight of each polymer, can lead to similar ranges of pore sizes and porosity.Table 5: The different polymers and their solution concentrations used during the electrospinning process for production of the outer component along with their pore sizes and porosity of the obtained layers. _

[0202] Solution

[0203] Polymer concentration Pore size (pm2) Porosity (%)

[0204] (wt / v %)

[0205] 5 0.050 ± 0.029 96 ± 2

[0206] 10 0.159 ± 0.088 94 ± 1

[0207] PCL (Mw: 80 kDa) 20 0.760 ± 0.598 91 ± 2

[0208] 25 2.144 ± 1.105 89 ± 3

[0209] 30 2.923 ± 1.210 88 ± 2

[0210] 5 - 97 ± 2

[0211] 10 1.611 ± 1.210 89 ± 2

[0212] PLA (Mw: 193 kDa) 12 3.160 ± 1.604 88 ± 3

[0213] 15 8.392 ± 4.698 82 ± 2

[0214] 20 4.410 ± 2.565 82 ± 1

[0215] 5 0.729 ± 0.571 96 ± 2 PVA(Mw: 140 kDa) 8 1.385 ± 1.020 95 ± 1

[0216] 10 1.661 ± 1.285 92 ± 2

[0217] PVA (Mw: 93 kDa) 10 1.429 ± 0.858 84 ± 2

[0218] To assess the effect of pore size on the release pattern of the volatile compound from the multicomponent structure, PCL was selected as the polymer. Different solution concentrations of 5% wt / v, 20% wt / v, and 30% wt / v were used to cover a wide range of pore sizes, from approximately 0.05 pm2to around 3 pm2. The type of polymer was kept constant to avoid interference from polymer type effects on the release profile. In a later stage, PCL and PLA with solution concentrations of 30% wt / v and 12% wt / v, respectively, were used to study the effect of polymer type on the release profile while maintaining a constant porosity of around 3 pm2.

[0219] Another critical aspect affecting the release pattern of the volatile compound from the multicomponent structure is the thickness of the outer component. The thickness of the prepared interconnected nanopore networks was assessed using SEM imaging of their cross-sectional view. For the study of release profiles from the multicomponent structures, the thickness of the nanoporous networks was adjusted to 0.1 mm and 0.3 mm.

[0220] Release profile

[0221] To realize the impacts of the outer components on the release profile of the active material from the inner component, stacking of the materials at different levels are studied. This investigation is carried out to prove the importance of using the multicomponent structure to finetune the release pattern of the volatilecompound. In this regard, the release of the mixture of oregano and cinnamon essential oils (EOs) with no release controlling media, the release of EOs absorbed in the starch film as the inner component and without the outer component of interconnected nanoporous network and the release of EOs from the multicomponent structure composed of the starch film as the inner component doped with the EOs and the interconnected nanoporous network made from 20 % wt / v solution of PCL via electrospinning are compared. In this experiment, no dilution or modification of the EO mix is utilized. Additionally, always a fixed quantity of EO is used. It should be noted that the study of the release profiles are conducted through weight loss measurement over 45 days and the study is carried out at room temperature.

[0222] The release profiles of each of the mentioned conditions are shown in Figure 18. According to this figure, the initial release of the EOs with no control and barrier on day 1 of the study is abrupt and it shows a burst release of more than 30 % of its initial weight which is due to the high volatility of the EOs. The release of the EOs occurs only for 9 days which then the release profile reaches a plateau. It should also be noted that, according to the data sheet provided by the supplier of the oregano and cinnamon essential oils, some non-volatile fillers are also used in these products. Due to the presence of such non-volatile fillers, which is more pronounced in case of the oregano oil, the release of the essential oils does not reach to 100 %. On the other hand, after absorption of the EOs in the starch film as the first release controlling barrier, the initial burst release is reduced to around 20 % of the initial weight of the used EOs followed by the release duration of around 21 days. This can be explained due to entrapment of the EOs in the pores of the starch film which act as a physical barrier for the release of EOs to the headspace, effectively doubling the release duration. This observation shows the effectiveness of loading the EOs in the inner component material to partially controlling the initial burst release. By comparing the release line of the two mentioned conditions, it can be seen that using the starch film slightly homogenizes the release pattern of the essential oil from this structure. Furthermore, by using the multicomponent structure, the initial burst release of the essential oil is prevented and reduced significantly to around 5 % of the initial used essential oil. Also, this structure has prolonged the release of the essential oil for more than 45 days (5 times of the EO without barrier and almost two times of using only the starch film as the release controller) while the release profile is more homogeneous without any abrupt release in between the time intervals. This is due to the presence of the interconnected network of the nanopores which the vapor molecules released from the starch film should go through before being released to the environment. This study proves the importance of using the multicomponent structure on the controlling the release of the volatile compounds in the environment.

[0223] To show the importance of the nano / micro size of the pores on the outer component, the release profile of oregano and cinnamon essential oil from the starch inner component without any outer component, from a starch inner component covered with a commercial non-woven textiles, such as the ones used conventionally for preparing aesthetic bags or sachets, and from the multicomponent structure composed of the starch inner component and the interconnected network of pores prepared from PCL solution with concentration of 20 % wt / v as the outer component is shown in Figure 19. It should be noted that the two mentioned essential oils are mixed and diluted with 65 % wt C7 oil and the release profile is obtainedthrough measuring the weight loss from the different systems through time and at room temperature. As shown in Figure 19, the release of essential oils on day 1 of the measurement from starch film and the starch film covered with the non-woven textile is in the same range and significantly higher than the one of the multicomponent structure. This shows the burst and uncontrolled release of the essential oil from such systems while in case of using the multicomponent structure, this initial release is controlled. This can be explained based on the presence of the nanoporous network which hinders the burst and uncontrolled release of the volatile compound, in this case the essential oils, from the system. On the other hand, it can be seen from Figure 19 that the release from the multicomponent structure is showing a controlled release on day 1 of the assessment preventing the burst release. Also, it should be noted that the release profile from the multicomponent structure is more robust and homogeneous through time and it is prolonged up to around 30 days while the release from the other two systems was only lasted for around 20 days. This observation can be explained through the presence of significantly fine pores in the outer layer based on the interconnected nanoporous network of PCL which hinders the release of the vapor from the essential oil in their network further proving the importance of using multicomponent structure with the mentioned outer component. On the other hand, it can be seen that there is no significant difference between the case using the non-woven textile for covering the starch film, and the case without the usage of a non-woven textile cover. Based on this observation we can conclude that using the nonwoven textile as outer component is not effective for the control of the release of the volatile compound, e.g. essential oil, from the system as such layers contain macroporous structures ineffective on hindering the release of vapors from the volatile compounds.

[0224] Eventually, this observation can show the effect of using nano sized pores on the release of the essential oil as by reducing the size of the pores to the range of nano size. The physiochemical properties of the materials will be more pronounced due to the enlarged surface area in contact with the molecules of the volatile being released to the environment.

[0225] Release profile of the multicomponent structure

[0226] To study the release profiles according to the different pore sizes used on the outer layer of the multicomponent system, only PCL as the polymer type for the outer layer is used to avoid the interference of the type of polymer on the release studies. On the other hand, to have higher precision of this study, analysis is peformed using a GC-MS headspace analysis at both room temperature and fridge temperature (4°C). For this matter, a range of pore sizes is selected for the interconnected network of pores as the outer layer. Using the 5 % wt / v solution of PCL results in the smallest pore size, while 20 % wt / v solution of PCL results in the medium pore size, and the 30 % wt / v solution of PCL results in the largest pore size after fabrication of the outer layer. Noteworthy, the outer layers are used with two different constant thicknesses of 0.1 mm and 0.3 mm to assess the effect of thickness of the outer layer combined with the effect of the pore sizes on the release profile. The two essential oils of oregano and cinnamon with equal quantities are diluted with C7 oil, with the final concentration consisting of 35 % for essential oils, and used as the volatile compound in the multicomponent structure. This mix is then absorbed by the starch film as the inner component. In order to study the release profiles, the main component of eachessential oil is detected and quantified in the headspace. In case of the cinnamon oil, the main component quantified in the headspace is Cinnamaldehyde while in case of oregano oil the main component is Carvacrol, as analyzed through GC-MS analysis of the two essential oils.

[0227] The release pattern of Cinnamaldehyde and Carvacrol from the multicomponent structures with the different outer layers based on PCL polymer mentioned above at room temperature and at 4° C are shown in Figure 20 and Figure 21 respectively.

[0228] The key outcomes of the figures are as follow:

[0229] The release of the cinnamaldehyde and carvacrol from the multicomponent systems are prolonged to around 50 days at room temperature and more than 70 days at 4° C

[0230] Compared to the method which the release profile is determined through weight loss, the duration of the release measured by GC-MS and at room temperature is longer, which is caused by the higher precision of GC-MS analysis in detecting the released compounds in the headspace

[0231] The initial release from the multicomponent structure using 30 % wt / v solution of PCL for preparing the nanoporous network is higher than those of 20 % wt / v and 5 % wt / v solution of PCL. This is due to the larger pore sizes of the nanoporous network in case of using 30 % wt / v solution of PCL which in turn results in larger quantities of the released volatile compounds

[0232] The initial release from the multicomponent structure using 5 % wt / v solution of PCL for preparing the nanoporous network is lower than the ones of 20 % wt / v and 30 % wt / v solution of PCL. This is due to the smaller pore sizes of the nanoporous network in case of using 5 % wt / v solution of PCL which in turn results in smaller quantities of the released volatile compounds

[0233] The release from the multicomponent structure using 30 % wt / v solution of PCL for preparing the nanoporous network is slightly faster than the multicomponent structures using 20 % wt / v, followed by 5 % wt / v solution of PCL for preparing the nanoporous network. It should also be noted that eventually, at the constant thicknesses of the outer component of either 0.1 mm or 0.3 mm, the release profile lines stop in the same approximate ratios for all the three different pore sizes used in the outer layer. This observation confirms the adjustment of release rate by changing the pore sizes while, due to using the same material for the outer layer in all cases, the interaction of the volatile compounds with the outer layer is solely based on the size of the pores, independent of the other physiochemical interactions

[0234] Increasing the thickness of the outer component has reduced the total release from the multicomponent structure, which is proof that the volatile compound, or in this case the essential oils, are passing through the nanoporous network and by increasing the thickness of this component, they are hindered by this network

[0235] The trends of the release profiles for the two thicknesses used for the outer layer are similar according to changes of the pore sizes

[0236] The total release at room temperature after 50 days is more than the ones at 4°C by order of 2 times, showing the effect of temperature on release profile. This observation is important for adjustment of the release quantities upon the final application based on the different temperaturesAt 4°C and for both cinnamaldehyde and carvacrol, the release profiles have not reached a plateau, which indicates the unfinished release period at this temperature. This can indicate that the release is not finished yet, and it can be prolonged for more than 70 days. This observation proves the importance of using the multicomponent structure as such for intensive control over the release of the volatile compounds to the headspace for extremely extended periods of time

[0237] The release of carvacrol from these multicomponent structures using PCL as the outer component material is less than cinnamaldehyde. This observation will be further explained in the following sections. In brief, this is due to the higher polarity of carvacrol compared to cinnamaldehyde, leading to the lower affinity of carvacrol to interact and pass through the extremely large surface area of the present PCL outer layer, which in turn leads to less released quantities.

[0238] The effects of environment’s relative humidity on the release profile

[0239] The environmental factors such as temperature and humidity are effective on the release pattern of the volatile compound from the multicomponent structure as the temperature can affect the volatility of the volatile compounds and humidity can affect the interaction of the volatile compounds with the inner and outer components and it can also affect the pores of the two components. Resultingly, it is important to be able to adjust the release profile according to environmental factors in order to have the optimum release according to the desired purpose. In this regard, the release of the Carvacrol and Cinnamaldehyde from the multicomponent structures at two different humidity of normal (around 40 % relative humidity) and 95 % relative humidity is studied in which oregano and cinnamon essential oils in the same quantity are used as the volatile compounds diluted with C7 oil, with a final concentration of 35 % of essential oils in the mix. This mix is then absorbed by the starch film as the inner component and the interconnected network of nanopores comprised of PCL as the polymer material is fabricated through electrospinning of 5 % wt / v of PCL solution. It should be noted that the study is conducted at room temperature and GC-MS analysis is used to analyze the headspace composition of the vials used during the study. The release pattern of the cinnamaldehyde and carvacrol are reported in Figure 22. As seen in the figure, by increasing the relative humidity, the release of both cinnamaldehyde and carvacrol from the multicomponent structure is reduced significantly to around half of the released quantity at normal humidity. This observation is due to the filling of the pores on the outer layer of the multicomponent structure with water vapor from the high humidity present in the environment which can hinder the release of the volatile compounds. As explained previously, the volatile compounds, in this case the essential oils, should go through the network of the nanopores, present at the outer layer before being released to the environment. In case of higher humidity at the headspace / environment, these network of the nanopores are filled by the water vapor which then reduce the present path for the volatile molecules. Additionally, in the presence of water vapor, the volatile molecules can be trapped in the vapor phase. These trapped molecules can be released upon the reduction of the relative humidity afterwards. By knowing the effect of humidity on the release of the volatile compounds, it is feasible to adjust the quantity of the used volatile compounds, pore sizes of the outer component layer and the material type of both inner and outer component in order to adjust the releasedquantities according to the desired target.

[0240] The effect of hydrophobicity and

[0241]

[0242] of the outer

[0243]

[0244] on the release

[0245]

[0246] To study the effect of the hydrophobicity of the outer component on the release profile of the volatile compound, in this study, two different polymers of PCL and PLA are used to prepare the outer component nanoporous network while keeping the pore sizes and porosities constant and at the same range. The solutions concentrations, pore sizes and porosity of the nanoporous network obtained from PCL and PLA solutions are reported in Table 6. The important aspect affecting the release of the essential oil from the multicomponent structure is the hydrophobicity of the material used in this outer component, which is an indication of its interaction with polar and non-polar materials. The water contact angle (WCA) is used to determine the hydrophobicity of a material which in this case, WCA is measured for the PCL and PLA both in the case of their smooth film as well as their nanoporous morphology with the same pore size ranges. This data is reported in Table 6 as well. According to the data of WCA both in morphology of film and nanoporous structure, it can be concluded that PCL is more hydrophobic than PLA. In other words, PLA has more polar functional groups in its surface, making it interact easier with the compounds of higher polarity.

[0247] As mentioned before, the main components of the oregano and cinnamon essential oils are Carvacrol and Cinnamaldehyde respectively, and from their chemical structure it can be determined that Carvacrol has a more polar structure than Cinnamaldehyde which can interact better with polar and more hydrophilic materials. The release profile of Carvacrol and Cinnamaldehyde present in the oregano and cinnamon oils used in the multicomponent structures are shown in Figure 23 for two temperatures of release (room temperature and at 4° C).Two different outer components from PCL and PLA with the same pore sizes and the same thickness of 0.1 mm are used in the multicomponent structure. It should be noted that the inner component and the diluent used in such structures are starch film and C7 oil and the same quantity of essential oils are used for each structure. In another word, all the parameters of the multicomponent structures used to study the release profiles are constant, expect for the polymer type used as the outer component. The release patterns reported are studied through headspace analysis of the vials containing the structures using GC-MS analysis. According to Figure 23, it can be seen that while using PLA as the polymer of the outer component layer, the release of carvacrol from the structure is increased, while the release of cinnamaldehyde is kept unchanged. This can be attributed to the polarity and hydrophilicity of the PLA polymer which carvacrol has higher affinity with this polymer. As a result, while passing the interconnected nanoporous network of the outer layer, higher affinity of carvacrol and PLA polymer leads to the ease of passage of Carvacrol and higher release of this compound from this structure. In case of using PCL, Carvacrol does not interact with this polymer and is trapped more inside the multicomponent structure. In other words: by reducing the pore sizes to nanosize, the surface area in which the volatile compounds should interact with is extremely enlarged which in turn the physiochemical aspects of the interactions between the volatile compound and the nanopores will be more pronounced. In this regard, the functionalities present on the outer layer material has higher effect on the interactions between thevolatile compound. With this data, it can be concluded that by changing the functionalities / polarity and hydrophobicity of the outer component and adjusting these properties by using a mix of different materials, the release profiles can be optimized and controlled further. In addition, it should be noted that this trend of release is observed at both temperatures of the study, proving further reliability of this observation as well as the ineffectiveness of temperature on the physiochemical interactions.

[0248] Table 6: The properties of the nanoporous networks obtained from PCL and PLA solutions for the outer component part of the multicomponent structure.

[0249] Properties PCL PLA

[0250] Solution concentration (% wt / v) 30 12

[0251] Pore size (pm2) 2.9 ± 2.0 3.1 ± 1.9

[0252] Porosity (%) 88 ± 2 88 ± 3

[0253] WCA of nanoporous network (°) 139.3 ± 0.7 127.1 ± 3.6 WCA of Film (°) 88.2 ± 2.7 60.1 ± 1.3

[0254] Weight-loss measurements performed on the multicomponent structures containing both the cinnamon and oregano oil with the same PCL and PLA nanofibrous structure as the outer components, confirmed the results of the GC-MS measurements (see Figure 27). As can be seen from Figure 27, the cumulative released content from the multicomponent structure composed of the PLA-based outer component is higher than the one from the multicomponent structure composed of the PCL-based outer component.

[0255] To further assess the effect of the interactions between the volatile molecules and the effective surface area of the porous layer outer component, the release patterns of two volatile agents from the multicomponent structure is studied. Volatile compounds 2-phenyethanol and citronellal are chosen for the study, which have a diverse range in their chemical structure and vapor pressure of 0.075 mmHg and 0.28 mmHg respectively. The choice of the polymers used for the fabrication of the outer layer of the multicomponent structure as well as their water contact angle properties in form of a two dimensional (2D) thin film without any morphological interference are listed in Table 8. As can be seen, cellulose acetate is the most hydrophilic choice for the fabrication of the outer component followed by PLA and PCL. Additionally, cellulose acetate is capable of forming hydrogen bonding with the surrounding environment which can further affect the interactions.

[0256] Table 7: The properties of the nanoporous networks obtained from PCL, PLA and cellulose acetate solutions for the outer component part of the multicomponent structure.

[0257] Properties PCL PLA Cellulose acetate Solution concentration (% wt / v) 30 12 20Pore size (pm2) 2.9 ± 2.0 3.1 ± 1.9 2.9 ± 2.1 Porosity (%) 88 ± 2 88 ± 3 88 ± 2 WCA of Film (°) 88.2 ± 2.7 60.1 ± 1.3 56.2 ± 2.1

[0258] From Figure 28a, showing the release profile of 2-phenylethanol, it can be seen that the release rate is higher in case of cellulose acetate as the polymer choice for the outer component, followed by PLA and PCL, respectively. Without willing to be bound by theory, it is believed that 2-phenylethanol, due to its hydrophobic nature, has more interactions and affinity towards the more hydrophobic PCL compared to the other two, more hydrophilic, polymers. It is further believed that this interaction leads to the entrapment of the volatile molecules on the large effective surface area of the PCL nanofibers, which hinders the release of the volatile.

[0259] From Figure 28b, showing the release profile of citronellal, it can be seen that the overall release rate and release quantity is higher than for 2-phenylethanol. It can moreover be seen that the difference in release rate of the three different polymers is more pronounced. It is believed that the more hydrophobic properties of citronellal as the volatile compound, in combination with the relative polarities of the different polymers, provides this more pronounced difference in release rates.

[0260] In other words, the multicomponent structure of the present invention, provides improved control over de the release rate and / or release quantity of the one or more volatile compounds.

[0261] The effect of morphology of the outer component on the release profile

[0262] The nanofibrous structure of the outer component acts as a 3D network of interconnected pores with very high surface areas, which enable the increased interactions between the volatile molecules and the polymer surface. In contrast, 2D films have a much lower surface area, typically 1-2 orders of magnitude lower surface area to volume (Wang, W. et al. Journal of Hazardous Materials, 194, 2011 , 185-192).

[0263] This difference in the morphological properties is further illustrated in Figure 29 showing the cross-sectional view of the PCL and PLA nanofibrous structures (Figures 29a-b), as used herein, compared to a cross-sectional view of a 2D film (Figure 29c, Ovaska, S-S et al. Polymers and Polymer Composites, 26 (4), 2018, 273-282).

[0264] In-vitro assessment of effectiveness of the multicomponent structure against fungal growth.

[0265] The effectiveness of using a multicomponent structure for the prevention of fungal growth is assessed using the film diffusion test method against three different fungi of the genera Aspergillus niger, Cladosporium and Penicillium chrysogenum. The results of these test are shown in Figure 30. For this study, as explained previously, different quantities of oregano and cinnamon essential oils are used in the multicomponent structure, with quantities ranging between 0 g (control) to 1 g (100 %). The plates inoculated with the fungal suspension and with the multicomponent structures were incubated for 14 days,after which they were assessed for the inhibition halo area. According to the results for Aspergillus niger, 1 g of the EOs should be loaded in the multicomponent structure for the complete inhibition of their growth while in case of the Cladosporium, even 0.2 g of EOs is effective for preventing the growth. On the other hand, in case of Penicillium chrysogenum, using 1 g of the EOs can be partially effective on the prevention of the growth of this fungi with the diameter of the inhibition halo being around 2.5 cm. Based on this observation, it can be concluded that for the more strong fungi type such as the genus Penicillium, the EO quantity to be used in the structure should be at least 1 g while this quantity is sufficient to prevent the growth of less strong fungi types.

[0266] Additionally, the fungal growth prevention is the result of both diffusion of the essential oils to the agar plates as well as the presence of the essential oil in the headspace through the release of it from the multicomponent structure which can prevent the growth of fungi at the further point from the multicomponent structure showing the importance of using such volatile compounds in their gaseous phase.

[0267] In-vivo assessment of effectiveness of using the multicomponent structure for the preservation of raspberries.

[0268] To assess the effectiveness of using the multicomponent structure as the release controller of the volatile compound in the headspace, this structure along with antimicrobial essential oils of oregano and cinnamon are used to preserve raspberries. Raspberries are delicate and precious fruits which without any preservation have significantly low shelf life around 5 days. In this regard, the prolongation of the product's shelf life, even by one additional day, may offer substantial advantages to retail businesses and commercial entities. . In this regard, its highly important to control their headspace composition with the right quantity of the preserves to prolong their shelf life. For this purpose, different quantities of 0.4 g, 0.8 g and 1 .2 g of oregano and cinnamon oil (EO) with the equal weights were diluted in C7 oil with 35 %wt of the mixture containing the two EOs were used as the volatile compound in the multicomponent structures containing starch film as the inner components and PLA-based interconnected nanoporous network with the pore size of around 3.1 pm2and thickness of 0.1 mm as the outer component. As described previously, the multicomponent structures were attached to the top lid of the containers with the raspberries and kept in the fridge for 7 days. The results of the raspberries at day 7 kept under different conditions of preservation are shown in Figure 24. It can be seen from the figure that on day 7 of the preservation, the raspberries kept along with the multicomponent structures containing 0.8 g and 1 .2 g of the EOs are showing no sign of mold or fungal growth, while at lower quantities of EO in the structure (0.4 g), small signs of decay are observed. On the other hand, the raspberried without any conservation method used as the control have already started to decay after 4 days being kept in the fridge and they are completely spoiled on day 7. According to this observation, it can be concluded that the multicomponent structures containing 0.8 g of the EO can effectively prevent the fungal growth on raspberries for 7 days. It should be noted that the raspberries kept under this condition started to show signs of decay on day 8 of the preservation. This data shows that this preservation method can prolongthe shelf life of a highly delicate product such as raspberries for around 50 % which can be useful for the retailers.

[0269] Additionally, as also explained before, during this study, the raspberries are kept in perforated containers and these containers were opened on daily basis for inspection of the raspberries which in both situations interfered with the headspace composition. In spite of the constant changes of the headspace composition and depletion of the headspace from the released essential oils daily, the raspberries kept along with the multicomponent structure including essential oils of more than 0.8 g, are preserved for a longer period of time. This is a proof that the release from the multicomponent structure is constant through a long time period, which can constantly keep the raspberries under the preservation of essential oils vapor. Also, this observation indicates that by using the right quantities of the volatile compound in the multicomponent structure, they can be incorporated in an open system as well which is important for a range of applications.

[0270] In-vivo assessment of effectiveness of using the multicomponent structure for the preservation of grapes.

[0271] To assess the effectiveness of using multicomponent structure to control the release of the essential oils in the headspace of a product for a longer period of time, in another study, grapes were selected to be protected against decay. For this purpose, two branches of grapes from the same main branch with the same qualities, without any treatment were selected and kept in closed plastic containers. In one of the containers the multicomponent structure containing 1 g of oregano and cinnamon oil is incorporated. The grapes that were kept under controlled conditions without the multicomponent structure in its container showed the first signs of fungal decay after 14 days. In order to have a better understanding of the effectiveness of using this technology on releasing the volatile compound, in this case the essential oils, within a prolonged period, the experiment was continued for 70 days. The condition of the two grapes kept for 70 days are shown in Figure 25. Figure 25a shows the grapes kept for 70 days with the multicomponent structure technology, while Figure 25b shows the grape without any preservation method. The grapes kept in the container including the technology is showing no sign of fungal decay and the grapes are only slightly dried while the grape kept without any preservation is fully covered with fungi. This experiment further strongly proves the importance of using a structure with the ability to release the essential and required volatile compounds in the headspace of a product for a prolonged period of time to extend their shelf life. In the case of grapes which have less delicacy compared to the raspberries, the shelf life is extended by 5 times which is breakthrough for this field.

[0272] In-vivo assessment of effectiveness of using the multicomponent structure compared to using essential oil with no release control for the preservation of plums

[0273] To prove the effectiveness of using the multicomponent structure as release controlling system compared to using the essential oils without any control over its release, the multicomponent structure containing oregano oil as the volatile compound is used for preservation of plums at room temperature while the plums are also kept along oregano oil with no encapsulation or release controlling system, as well as plums without any preservation method for sake of comparison. The plums of the mentioned conditionswere kept at room temperature and their conditions are shown in Figure 26. Figure 26a shows the condition of plum kept under preservation using the multicomponent structure after 14 days of preservation while Figure 26b shows the condition of plum kept without any preservation method after 14 days kept at room temperature and Figure 26c shows the condition of plum kept with oregano oil for 14 days at room temperature while no release controlling system for the oil is utilized. It can be seen from the figure that the plum kept with the multicomponent structure shows no sign of decay after 14 days of preservation showing the effectiveness of using such system for release of essential oils in the headspace while the plum with no preservation method is totally rotted after 14 days. On the other hand, the plum kept with the oregano oil with no barrier over its control, shows less decay compared to the condition of not using any preservation method but this plum has some traces of decay as brownish stripes and spots in the structure of the plums. Noteworthy, the plum kept under no preservation system started to decay after 5 days kept at room temperature while the one kept along the oregano oil showed the first signs of decay after 9 days kept at room temperature. This observation shows the importance of controlling the release of the volatile compounds, in this case the essential oil, for benefiting from the efficacy for a longer period of time and better extension of the shelf life of products. In this study, the shelf life of products utilizing the multicomponent structure could be extended for about 3 times while with no control over the release of the oregano oil, the shelf life is only extended for around 2 times.

[0274] In-vivo assessment of effectiveness of using the multicomponent structure for the preservation of eclairs To assess the effectiveness of using multicomponent structure to control the release of the active agent such as citronellal in the headspace of a product for a longer period of time, in another study, eclairs were selected to be protected against decay. For this purpose, commercially available eclairs were obtained directly from the producer to make sure of their freshness and were kept in plastic containers provided by the producer. In three of the containers the multicomponent structure containing 0.5 g of citronellal is incorporated. The eclairs that were kept under controlled conditions without the multicomponent structure in its container showed the first signs of structural change after 5 days of storage which they absorbed the accumulated moisture in the container. On the other hand, the containers including the multicomponent structure showed no sign of moisture accumulation and the eclairs kept their fresh and firm structure. This can be explained by the fact the incorporation of the starch-based inner component act as the moisture absorbent component in the package effectively keeping eclairs fresh. The eclairs in the containers containing the multicomponent structure kept their structural firmness for 14 days while the control samples already lost their firmness after 5 days. This property can be used in addition to the microbial growth prevention as one of the effective parameters on the packed food spoilage is the moisture accumulation in the package which can accelerate the decay. It should be noted that as the eclair contain fat and sugar in its composition, the microbial decay through fungal growth is not observed after 14 days of preservation.

[0275] In-vivo assessment of effectiveness of using the multicomponent structure for the preservation of par-baked bread.To assess the effectiveness of using multicomponent structure to control the release of the active agent such as 2-phenylethanol in the headspace of a product for a longer period of time, in another study, par-baked breads including a piece of butter were selected to be protected against decay. For this purpose, store-bought par-baked breads with the butter were kept in plastic containers with two conditions of with multicomponent structure and without any preservation at room temperature. Based on the observations, the control samples showed fungal growth after 2 weeks of storage while the breads in the other container had no sign of spoilage. Another important observation was the moisture accumulation in the control packs while the packs containing the multicomponent structure didn’t show any sign of the moisture accumulation. The test continued for 1 month which the breads in the containers with the multicomponent structure didn’t show any sign of spoilage or mold growth while the control bread was covered by mold and fungi.

[0276] In-vivo assessment of effectiveness of using the multicomponent structure for the preservation of beef meat

[0277] To assess the effectiveness of using multicomponent structure to control the release of the active agent such as 2-phenylethanol in the headspace of a product for a longer period of time, in another study, beef meat stocks were selected to be protected against decay. For this purpose, store-bought beef meat stocks were kept in plastic containers with two conditions of with multicomponent structure and without any preservation in the fridge at 7° C. After 1 week of storage at fridge temperature, the control sample started to generate rotten smell while the beef meat stored with the multicomponent structure had the fresh smell. At this stage no difference between the structure and color of the two groups. After 10 days of the storage, the control sample started to show oxidized and browned color while the preserved sample still was red on the color. Another important observation was the moisture accumulation in the control packs which was higher than the sample stored with the multicomponent structure which shows the effectiveness of using the multicomponent structure for the preservation of products against both microbial growth and moisture.

[0278] In-vivo assessment of effectiveness of using the multicomponent structure for the preservation of strawberries at room temperature in open package

[0279] To assess the effectiveness of using multicomponent structure to control the release of the active agent such as 2-phenylethanol in the headspace of a product in format of an open package system for a longer period of time, in another study, strawberries were selected to be protected against decay. For this purpose, store-bought strawberries were kept in plastic containers with two conditions of with multicomponent structure and without any preservation at room temperature while the package of the strawberries for each condition was kept open and the two conditions of the storage were kept separately for prevention of the influence of volatile release on the control samples. After 3 days of storage, the control sample was covered with fungi and mold while the strawberries stored with the multicomponent structure kept their structure and showed no sign of microbial growth. The test was carried out for 6 days which the strawberries kept with the multicomponent structure still showed no sign of microbial decay(shown in Figure 31 ) and after day 6, the structure of the strawberries started to get softer and juicer. This study proves that using the multicomponent structure even at room temperature and with open packaging can prolong the shelf life of products to 100 %. The condition used in this test was extreme as the storage temperature was rather high for a delicate product such as strawberries and they were kept in the open package which the emitted volatiles could not be accumulated and kept in the package. This way, we proved the constant and prolonged release of the volatile form this multicomponent structure.

Claims

-43- CLAIMS1 . A multicomponent structure for releasing one or more volatile compounds, the structure comprising:at least one outer component; andat least one inner component fully enclosed by the at least one outer component;wherein the at least one inner component comprises at least one porous material, and one or more volatile compounds having an overall vapor pressure from 200 Pa to 200 kPa at 20 °C, at least partially contained within the at least one porous material; andwherein the at least one outer component comprises, or consists of, a porous layer of polymer fibres, the porous layer having a thickness from 0.01 to 10 mm, wherein the pores between the fibres form a 3D network of interconnected pores with pore sizes ranging from 0.01 pm2to 20 mm2.

2. Multicomponent structure as claimed in claim 1 , wherein the one or more volatile compounds are biogenics, biochemicals, organic or inorganic compounds and / or have one or more of the following properties: antimicrobial, antibacterial, antifungal, antimould, deodorant, insect repellant, pesticidal, insecticidal, fungicidal, herbicidal, plants- fruits- and vegetable respiratory inhibitor, reactive oxygen species emitting, flavoring, horticultural effect, plant growth factors, ethylene blockers / inhibitors, CO2 emitters, perfumes, or flavors.

3. Multicomponent structure as claimed in claim 1 , wherein the one or more volatile compounds are selected from one or more of the following: essential oils, such as oregano oil, cinnamon oil, lavender oil, clove oil, frankincense oil, peppermint oil, eucalyptus oil, lemongrass oil, orange oil, rosemary oil, bergamot oil, cedarwood oil; active components of essential oils, such as carvacrol, cinnamaldehyde, eugenol, isoeugenol, thymol; ethylene synthesis inhibitors, such as 1 -methylcyclopropene; alcohols, such as ethanol; perfumes; short-chain organic acids, such as butyric acid; aldehydes, such as glutaraldehyde; ketones, such as methyl ether ketone; sulfur containing compounds, such as sulfur dioxide; nitrogen containing compounds, such as nitrous oxide; chlorine containing compounds, such as chlorine dioxide; plant derived volatiles, such as allyl isothiocyanate and methyl anthranilate; pheromones; secondary metabolites of microbes, such as furanone; and ozone.

4. Multicomponent structure as claimed in any of claims 1 to 3, wherein the polymer fibres are prepared from a polymer selected from polyolefins, polyesters, polyurethanes, polyvinyl chloride (PVC), polyvinyl alcohol (PVA), or biopolymers.

5. Multicomponent structure as claimed in claim 4, wherein the polymer fibres are formed by electrospinning a polymer material, in particular selected from one or more of the following: polyvinyl alcohol (PVA), polylactic acid (PLA), or polycaprolactone (PCL).

6. Multicomponent structure as claimed in any of claims 1 to 5, wherein the pore sizes range from 0.02 to 500 pm2, preferably from 0.03 to 200 pm2, more preferably from 0.04 to 100 pm2, even more-44- preferably from 0.05 to 50 pm2, yet even more preferably from 0.10 to 25 pm2, yet even more preferably from 0.25 to 15 pm2, yet even more preferably from 0.50 to 10 pm2, yet even more preferably from 0.75 to 5 pm2, yet even more preferably from 1 to 4 pm2, yet even more preferably from 2 pm2to 3 pm2.

7. Multicomponent structure as claimed in any of claims 1 to 6, wherein the thickness of the permeable portion is from 0.025 to 1 mm, preferably from 0.05 to 0.9 mm, more preferably from 0.1 to 0.8 mm, even more preferably from 0.15 to 0.7 mm, yet even more preferably from 0.20 to 0.6 mm, yet even more preferably from 0.25 to 0.5 mm, yet even more preferably from 0.3 to 0.4 mm.

8. Multicomponent structure as claimed in any of claims 1 to 7, wherein the at least one porous material has a loading capacity of the one or more volatile compounds of 10 to 500 wt.%, preferably from 15 to 300 wt.%, more preferably from 20 to 200 wt.%, even more preferably from 25 to 100 wt.%, yet even more preferably from 30 to 75 wt.%, yet even more preferably from 40 to 60 wt.%.

9. Multicomponent structure as claimed in any of claims 1 to 8, wherein the at least one porous material is selected from or more of the following: an inorganic material, such as zeolite, clay, alumina, silica or bentonite; a biopolymer, such as starch, cellulose, amylose, chitosan, alginate, or gums; or a synthetic polymer, such as polyolefin, or polyurethane.

10. Multicomponent structure as claimed in any of claims 1 to 9, wherein the at least one inner component further comprises one or more diluents, at least partially contained in the at least one porous material, and preferably selected from one or more of the following: water; an alcohol, such as methanol, ethanol, isopropanol; a vegetable oil, such as sunflower oil, olive oil, grapeseed oil, coconut oil; a vegetable oil fraction or derivate, such as fatty acids, fatty acid esters; emulsifiers; glycerol triheptanoate oil and cyclomethicone.

11. Method for preparing the multicomponent structure as claimed in any of claims 1 to 10, comprising the steps of:a) impregnating at least one porous material with one or more volatile compounds, thereby providing at least one inner component; andb) at least partially enclosing the at least one inner component by at least one outer component.

12. Method as claimed in claim 11 , further comprising the step of mixing the one or more volatile compounds with one or more diluents, thereby providing a mixture, and impregnating the at least one porous material with the mixture, thereby providing the at least one inner component.

13. Method as claimed in claim 11 or 12, further comprising the step of electrospinning a polymer material, thereby providing the at least one outer component as a layer of polymer fibres, and fully enclosing-45- the at least one inner component with the layer.

14. Use of the multicomponent as claimed in any of claims 1 to 10, for preservation, shelf life increase, deodorisation, insect repelling and / or pest control.

15. Use as claimed in claim 14, wherein the one or more volatile compounds are released from the multicomponent structure for at least 30 days, preferably at least 40 days, more preferably at least 50 days, even more preferably at least 60 days, yet even more preferably at least 70 days.

16. Controlled release packaging, comprising:a container; andthe multicomponent structure as claimed in any of claims 1 to 10.

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