Packaging and method for preserving respiring produce

Abstract

A package for preserving respiring produce, particularly vegetables, fruits, herbs, spices and / or flowers, contained therein, and an associated method are provided, the package defining a package volume and a package atmosphere for containing a portion of the produce, and comprising a packaging material, particularly a BOPE or MDOPE-containing polymeric film having a haze of 10 or less, preferably 5 or less, more preferably 3 or less, and most preferably 2 or less, and provided with one or more perforations to allow gas exchange with the atmosphere surrounding the package, to form the package into a controlled atmosphere package (CAP). The package has a carbon dioxide transmission rate (CO2TR pack ) and the CO2TR pack but at least 1000ml / 24 hours per 100 grams of produce to be packaged.

Description

[Technical field]

[0001] The present disclosure relates to a package for preserving respiring produce, particularly vegetables, fruits, flowers and herbs, contained therein, the package comprising a packaging material, particularly a polymeric film, the package being provided with one or more perforations allowing gas exchange, particularly oxygen and carbon dioxide exchange, with the external atmosphere surrounding the package. The present invention further relates to a method for producing such a package. [Background technology]

[0002] Shelf life of natural products is of concern to producers, sellers, resellers and consumers alike. In the case of food products, such as those mentioned above including vegetables, fruits, herbs and / or spices, taste, flavour, ripeness and / or structural properties (e.g. firmness) are particularly relevant, as well as inhibiting spoilage processes and / or pathogen growth. In the case of flowers, a particular concern is the so-called vase life, i.e. the time that cut flowers and / or flowers in bouquets retain an acceptable beautiful appearance and / or fragrance on display. Typically, the vase life is a few days to at most two weeks. Shelf life and vase life are influenced by the quality of the initial produce, as well as the conditions of storage and / or transportation.

[0003] Natural produce, such as flowers, vegetables, fruits and / or herbs, tends to respire after harvest, involving, among other things, the consumption of oxygen and the production of carbon dioxide. Respiration continues for a long period of time, especially when the produce is little processed, for example washed and possibly peeled and / or chopped, but otherwise fresh and uncooked. When such produce is packaged, the atmosphere inside the package is influenced by the respiring produce. Conversely, the atmosphere surrounding the natural produce influences the respiration, maturation, aging and / or deterioration of the packaged produce. It is therefore customary to package fresh produce using Modified Atmosphere Package (MAP) or using Controlled Atmosphere Package (CAP). In MAP, the produce is packaged and an artificial gas mixture is used to establish a unique atmosphere inside the package, which, however, may later change due to the respiration of the packaged produce. In CAP, the produce is packaged and the composition of the packaging atmosphere is controlled by including active absorbents for atmosphere components, e.g., oxygen scavengers, and / or by adapting the permeability of the outer packaging material to allow exchange with the external atmosphere outside the package, e.g., by piercing the packaging material. Modified and controlled atmosphere packaging (MAP / CAP) preserves the quality of the produce by reducing the rate of aerobic respiration while avoiding anaerobic processes that may adversely affect, e.g., one or more of color, texture, flavor, and aroma.

[0004] Another aspect of perishable and / or respiring produce is, on the one hand, the production of water vapour by the produce and, on the other hand, the susceptibility to humidity by the produce and / or live contaminants (e.g. microorganisms, insects, parasites and fungi). Therefore, the humidity of the atmosphere within the package should also preferably be controlled.

[0005] In view of the above, different packages and packaging materials have been developed, see, for example, International Publication No. WO2016 / 071922 or International Publication No. WO2016 / 003899. It is further noted that various aspects of modified / controlled atmosphere packaging are disclosed in US Pat. No. US7,083,837 and PV Mahajan et al., "An interactive design of MA-packaging for fresh produce", in: "Handbook of food science, technology and engineering", YH Hui (ed), CRC Press (Taylor & Francis Group) 2006.

[0006] Additional aspects related to packaging materials and / or packaging of respiring produce are described in EP 2,294,923, U.S. Patent Application Publication No. US 2010 / 221393, WO 2017 / 220801, U.S. Patent Application Publication No. US 2010 / 151166, WO 2018 / 147736, WO 2009 / 003675, German Patent Application No. DE 69,901,477, and in M. Mastromatteo, et al., "A new approach to predict mass transport properties of micro-perforated films intended for food packaging applications", J. Food. Eng. 113 (1): 41-46. (2012-05-18), DOI: 10.1016 / J.JFOODENG.2012.05.029; and M. Scetar, et al., "Trends in Fruit and Vegetable Packaging - a Review", Croatian J. Food Tech., Biotech. Nutr., 5(3-4): 69-86 (2010), ISSN: 1847-3423.

[0007] US Patent No. 6,376,032 describes a gas-permeable membrane useful in packaging fresh-cut fruits and vegetables, as well as other respiring biological materials. The membrane is produced by forming a thin polymer coating on a microporous polymer film. The preferred coating polymer is a side-chain crystalline polymer, such as a polyacrylate, which is applied onto the microporous membrane by solution coating.

[0008] U.S. Pat. No. 6,441,340 describes micro-perforated packaging material for use in modifying or controlling the flow of oxygen and carbon dioxide into and / or out of a container of fresh produce, where the micro-perforations are specially tailored in size, location and number for a particular fresh produce; a packaging system that designates a container with specially tailored micro-perforations for a particular fresh produce to optimally preserve the produce; and a method of forming registered micro-perforations in the packaging material using a CO2 laser and sensor mechanism.

[0009] US Patent Application Publication No. US2015 / 321823 is based on the synergistic effect of a cyclopropene compound and a modified atmosphere package to extend the shelf life and / or preservation of avocados. There is provided a method for preserving avocados, comprising exposing the avocados to an atmosphere containing a cyclopropene compound, where either (a) the avocados are in a modified atmosphere package during exposure to the cyclopropene compound, or (b) the avocados are placed in a modified atmosphere package after exposure to the cyclopropene compound, and the avocados remain in the modified atmosphere package for at least 2 hours. In some embodiments, the modified atmosphere package is constructed such that the oxygen transmission rate for the entire package is between 200 and 40,000 cubic centimeters per kg of avocado per day. Summary of the Invention [Problem to be solved by the invention]

[0010] However, in view of the continuing effort to improve the quality of produce and prevent spoilage and loss, further improvements are still desired. This is particularly the case for packages for freshly cut leafy greens. This type of produce is particularly prone to decay and spoilage. Therefore, packages for these types of produce still leave much to be desired, especially with regard to transparency and shelf life. [Means for solving the problem]

[0011] BRIEF SUMMARY OF THE DISCLOSURE There is now provided a package for preserving respiring produce, and a method for making the package for preserving respiring produce contained within the package, as specified in the accompanying claims.

[0012] 1. A package for preserving respiring produce contained within the package, the package defining a package volume and a package atmosphere for containing a portion of the produce, the package comprising: A packaging material comprising a polymer film containing biaxially oriented polyethylene (BOPE) or monodirected oriented poly ethylene (MDOPE) having a haze of 10 or less, preferably 5 or less, more preferably 3 or less, and most preferably 2 or less, as determined by ASTM D 1003. Including, wherein the polymeric film is provided with one or more perforations to allow gas exchange with the atmosphere surrounding the package to form the package into a Controlled Atmosphere Package (CAP); Here, the packaging material has a carbon dioxide transmission rate (CO2TR mat ), and The carbon dioxide permeability (CO2TR pack) is the carbon dioxide transmission rate (CO2TR perf ) and the carbon dioxide transmission rate (CO2TR mat ) and CO2TR pack =CO2TR perf +CO2TR mat The one or more perforations have a carbon dioxide transmission rate (COTR) of the perforations. perf ) and The CO2TR pack is at least 1000 ml / 24 hours, preferably at least 1500 ml / 24 hours, more preferably at least 2000 ml / 24 hours, and most preferably at least 2500 ml / 24 hours per 100 grams of produce to be packaged. The above packaging.

[0013] The packages of the present disclosure may be suitable for use with any respiring produce, such as freshly cut leafy greens, freshly cut vegetables, fruits, herbs, flowers, or prepared salads.

[0014] The fresh cut leafy vegetables may include lettuce, arugola, spinach, romaine, and combinations thereof.

[0015] The fresh cut vegetables may include beans, zucchini, carrots, sprouts, leeks, cauliflower, broccoli, and combinations thereof.

[0016] The fresh fruits may include berries, apples, stone-fruits (e.g., mangoes), pears, tomatoes, peppers, bananas, grapes, and the like, and combinations thereof.

[0017] The prepared salad may include fresh cut leafy greens, and / or fresh cut vegetables, and / or fresh fruit.

[0018] The thickness of the polymer film layer is in the range of 5 to 200 micrometers, preferably in the range of 10 to 150 micrometers, more preferably in the range of 15 to 100 micrometers, even more preferably in the range of 20 to 75 micrometers, and most preferably in the range of 15 to 50 micrometers.

[0019] The packaging material has an oxygen transmission rate (O2TR pack ) and oxygen transmission rate (O2TR perf The package has an oxygen transmission rate (O2TR pack ) is the oxygen transmission rate (O2TR perf ) and the oxygen transmission rate (O2TR mat ) and the total (O2TR pack =O2TR perf +O2TR mat The transmittance b of the packaging material pack But, b pack =(CO2TR perf +CO2TR mat ) / (O2TR perf +O2TR mat The transmittance b of the packaging material pack =CO2TR pack / O2TR pack is at least 1.5, preferably at least 2, more preferably at least 3, even more preferably at least 4, for example 5 or more.

[0020] The packaging material has a capacity of at least 2000 ml / (m 2.24 hours), preferably at least 3000 ml / (m 2 24 hours), more preferably at least 4000 ml / (m 2 24 hours), most preferably at least 5000 ml / (m 2 .24 hours), oxygen transmission rate (O2TR mat ).

[0021] The packaging material has a carbon dioxide transmission rate (COTR) of at least 15000 ml / (m2.24 hr), preferably at least 20000 ml / (m2.24 hr), more preferably at least 25000 ml / (m2.24 hr), and most preferably at least 30000 ml / (m2.24 hr). mat ).

[0022] A package according to the present disclosure may also be in the form of a tray and a lid film sealed to the tray, thus closing the package, in which case the lid film is a Biaxially Oriented Poly Ethylene (BOPE) or Mono Directed Oriented Poly Ethylene (MDOPE) containing polymer film.

[0023] The present disclosure further provides a method for manufacturing a package for preserving respiring produce contained within the package, the method comprising: i. providing a closed package defining a package volume for containing a portion of the respiring produce within the package volume from a packaging material comprising a biaxially oriented polyethylene (BOPE) or unidirectionally oriented polyethylene (MDOPE) containing polymeric film having a haze of 10 or less, preferably 5 or less, more preferably 3 or less, and most preferably 2 or less, as determined by ASTM D 1003; and ii. the package has a carbon dioxide transmission rate (COTR) of at least 1000 ml / 24 hours, preferably at least 1500 ml / 24 hours, more preferably at least 2000 ml / 24 hours, and most preferably at least 2500 ml / 24 hours per 100 grams of produce to be packaged; pack determining the size and possibly the number of perforations that are or are to be provided in the packaging material to allow gas exchange between the package atmosphere and the atmosphere surrounding the package, so as to form the package into a controlled atmosphere package (CAP); The present invention is directed to the above method, which includes:

[0024] A suitable packaging material for the method has a capacity of at least 2000 ml / (m 2 .24 hours), preferably at least 3000 ml / (m 2 24 hours), more preferably at least 4000 ml / (m 2 24 hours), most preferably at least 5000 ml / (m 2 It may have an oxygen transmission rate (O2TR) of 0.24 hours.

[0025] Suitable packaging materials for the method have a carbon dioxide transmission rate (CO2TR) of at least 10,000 ml / (m 2 .24 hours), preferably at least 12000 ml / (m 2 24 hours), more preferably at least 15000 ml / (m 2 24 hours), most preferably at least 20,000 ml / (m 2 .24 hours).

[0026] A method of manufacturing a package for preserving respiring produce contained therein is also directed to producing a tray and a lidding film sealed to the tray, thus closing the package, wherein the lidding film is a biaxially oriented polyethylene (BOPE) or unidirectionally oriented polyethylene (MDOPE) containing polymer film. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] [Detailed Description] The present disclosure provides a package for storing respiring produce, and a method for making the package for storing respiring produce contained within the package, as set forth in the accompanying claims.

[0028] More particularly, the present disclosure relates to a package for preserving respiring produce contained within the package, the package defining a package volume and a package atmosphere for containing a portion of the produce, the package comprising: A packaging material comprising a polymer film containing biaxially oriented polyethylene (BOPE) or monodirected oriented poly ethylene (MDOPE) having a haze of 10 or less, preferably 5 or less, more preferably 3 or less, and most preferably 2 or less, as determined by ASTM D 1003. Including, wherein the polymeric film is provided with one or more perforations to allow gas exchange with the atmosphere surrounding the package to form the package into a Controlled Atmosphere Package (CAP); Here, the packaging material has a carbon dioxide transmission rate (CO2TR mat ), and The carbon dioxide permeability (CO2TR pack ) is the carbon dioxide transmission rate (CO2TR perf ) and the carbon dioxide transmission rate (CO2TR mat ) and CO2TR pack =CO2TR perf +CO2TR mat The one or more perforations have a carbon dioxide transmission rate (COTR) of the perforations. perf ) and oxygen transmission rate (O2TR perf ) and The CO2TR packis 1000 ml / 24 hours, preferably at least 1500 ml / 24 hours, more preferably at least 2000 ml / 24 hours, and most preferably at least 2500 ml / 24 hours per 100 grams of produce to be packaged. This is directed to the above-mentioned packaging.

[0029] The packaging material used is a biaxially oriented polyethylene (BOPE) or unidirectionally oriented polyethylene (MDOPE) containing polymer film. When a polyethylene film is extruded and stretched in both the machine direction and the cross machine direction, it is called biaxially oriented polyethylene. When an extruded polyethylene film is stretched in only one direction, it is called mono directed oriented polyethylene. BOPE and MDOPE films may be multi-layered. For example, BOPE or MDOPE containing films may also comprise a printable layer and / or a heat sealable layer on a polyethylene core layer. The various layers may optionally be provided with intermediate layers to provide the necessary compatibility between the layers. Preferably, the various layers are polyethylene layers. BOPE and MDOPE films have higher tensile strength and impact strength than conventional polyethylene films BOPE films. Furthermore, BOPE and MDOPE can be produced with high transparency. Since the packages according to the present disclosure are used to preserve agricultural products, the transparency of the packaging material is important. Customers want to be sure that they are aware of the quality and freshness of the produce. BOPE and MDOPE containing polymer films having a haze of 10 or less, preferably 5 or less, more preferably 3 or less, most preferably 2 or less, as determined by ASTM D 1003, are suitable for the packaging of the present invention. Due to their higher mechanical strength, BOPE and MDOPE containing polymer films may be prepared with reduced thickness, resulting in a reduced amount of plastic used, thus reducing costs and reducing waste. Moreover, BOPE and MDOPE are 100% recyclable. The inventors have found that this type of material is particularly suitable for creating micro-perforations in a reproducible manner with very uniform perforations. The inventors have also found that BOPE and MDOPE have a very high CO2 permeability and β ratio as well as a high water vapor transmission rate compared to conventional polyethylene. These properties make the packaging material very suitable for use in packaging according to the present disclosure.It is even possible to tailor the package to the particular produce to be packaged.

[0030] Biaxially oriented polyethylene (BOPE) films are known in the art. For example, International Publication WO 97 / 22470 describes BOPE films and methods for their manufacture. In this example, several films are prepared and oriented. The disclosed properties of the films include oxygen transmission rate and water vapor transmission rate. The publication does not mention the CO2 transmission rate of the films.

[0031] As described in the above brochure, different species of produce and different varieties within a species of produce are known to exhibit different respiration rates. The total open area of ​​the perforations for the CAP should be determined based on the permeability characteristics of the produce to be packaged and the packaging material itself. The permeability of the package for each substance is formed by a combination of the permeability of the packaging material and the permeability through the perforations for each substance.

[0032] The packaging of the present disclosure can be suitably used for any respiring produce, such as fresh cut leafy vegetables, fresh cut vegetables, fruits, herbs, flowers, or prepared salads. As mentioned above, the BOPE or MDOPE-containing polymeric film allows the conditioning of any respiring produce into the packaging. The inventors have found that this can be done by setting the carbon dioxide transmission rate of the packaging to at least 1000 ml / 24 hours per 100 grams of produce to be packaged. The impact of carbon dioxide reaching harmful levels is much higher for leafy vegetables, such as spinach, than for dense vegetables, such as green beans or brussels sprouts, because the surface area per weight of spinach is much greater than that of green beans. Thus, the present disclosure provides a packaging suitable not only for high-demand produce, such as leafy vegetables, but also for dense vegetables, such as green beans or brussels sprouts. The parameter CO2TR per 100 grams of produce package takes into account differences in produce density. This parameter was not disclosed in the above mentioned brochure and its relevance was not acknowledged.

[0033] Examples of fresh cut leafy vegetables are lettuce, arugula, spinach, romaine, and combinations thereof.

[0034] For these fresh cut leafy vegetables, the CO2TR per 100 grams of package is preferably 1500ml / 24hrs, more preferably 2000ml / 24hrs, most preferably 2500ml / 24hrs.

[0035] Examples of fresh cut vegetables are beans, zucchini, carrots, sprouts, leeks, cauliflower, broccoli, and the like, and combinations thereof.

[0036] Examples of fresh fruits are berries, apples, pears, tomatoes, peppers, bananas, mangoes, grapes, stone fruits (eg, mangoes, grapes), and the like, and combinations thereof.

[0037] Packaging according to the present disclosure may also be suitable for use for ready-to-eat salads, which may include fresh cut leafy greens, and / or fresh cut vegetables, and / or fresh fruit.

[0038] As mentioned above, BOPE and MDOPE can be prepared in smaller thicknesses than conventional polyethylene due to their high mechanical strength. In addition to the renewable nature of these types of films, these reduced thicknesses also have advantages in terms of cost and environmental impact.

[0039] The thickness of the polymer film layer is in the range of 5 to 200 micrometers, preferably in the range of 10 to 150 micrometers, more preferably in the range of 15 to 100 micrometers, even more preferably in the range of 20 to 75 micrometers, and most preferably in the range of 15 to 50 micrometers.

[0040] The packaging material has a carbon dioxide transmission rate CO2TR mat and an oxygen transmission rate O2TR. The package has a carbon dioxide transmission rate CO2TR of the package. pack and oxygen permeability rate O2TR pack , and a permeability b of the package of at least 1.5, preferably at least 2, more preferably at least 3, even more preferably at least 4, for example 5 or more. pack =CO2TR pack / O2TR pack has.

[0041] Thus, the entire package provides a high permeability ratio between the permeability ratios for oxygen and carbon dioxide.

[0042] Carbon dioxide permeability promotes the egress of carbon dioxide, thus mitigating the build-up of CO2 concentration in the packaging atmosphere, and thus reducing or preventing the risk of anaerobic decay processes. Furthermore, CO2 can dissolve in water, from which it may subsequently re-enter the packaging atmosphere, and react with water to form carbon dioxide, which may affect the taste and / or composition of food produce stored within the package.

[0043] When a package containing respiring produce is closed, the oxygen in the package atmosphere is consumed and the oxygen concentration decreases.

[0044] Too low an O2 concentration can accelerate anaerobic decay processes, however too high a concentration can accelerate staling of produce. Both should be prevented. The oxygen transmission rate O2TR of the package allows the inflow of oxygen into the packaging atmosphere and prevents its complete consumption.

[0045] Typically, oxygen concentrations in the range of 1-10%, preferably 2-8%, e.g., 3-7%, more preferably 4-6%, may be preferred to slow down the staling process (also known as "restoring the produce") and maximize shelf life. Such concentrations may be achieved by one or more perforations forming the package as a CAP. The one or more perforations may increase the oxygen transmission rate of the package as a whole.

[0046] Core perforation affects the oxygen and carbon dioxide permeability of the entire package. pack facilitates control of the oxygen and carbon dioxide concentrations in the packaging atmosphere by perforating the packaging material with one or more perforations, such that increased inflow of oxygen and increased outflow of carbon dioxide can be balanced by the one or more perforations.

[0047] The one or more perforations may be provided as one or more microperforations. When the package is formed into a CAP, it should have no openings other than those provided by the one or more perforations in order to precisely control the package atmosphere.

[0048] It should be noted that the water vapor transmission rate of the package is only slightly affected by the open area of ​​the microperforations for the CAP.

[0049] In one embodiment, the one or more perforations may comprise microperforations having an open area of ​​less than 1 square millimeter, preferably less than 0.5 square millimeter, for example about 0.25 square millimeter or less. Such microperforations facilitate the exchange of gas through the packaging material, but prevent contamination of the packaging material from external sources. Such microperforations may be performed by (hot) needles. Laser perforation is an effective modality for providing such microperforations quickly, reliably, food-safe, and at the desired location. Microperforations also tend not to significantly impair the integrity of the packaging material, especially when the perforated packaging material comprises a polymeric film. Suitable films may range from flexible films that can be bent and / or folded multiple times without damage, to rigid films for making trays.

[0050] The laser-drilled microperforations may be approximately circular or oval and may have a (maximum) diameter in the range of 50 to 500 micrometers, in particular in the range of 60 to 400 micrometers, preferably in the range of 70 to 200 micrometers, more preferably in the range of 80 to 150 micrometers, for example in the range of 90 to 120 micrometers.

[0051] Determining the oxygen and / or carbon dioxide permeability provided by a perforation may include determining the open area and membrane thickness. In the case of generally circular, elliptical or oval perforations, the open area may be determined by determining based on one or more diameters determined from the hole, and camera images may be used for that purpose. A suitable computational model is provided in Fishman et al., "Mathematical model for perforation effect on oxygen and water vapor dynamics in modified atmosphere packages", J. Food Sci. 61(5):956-961 (1996).

[0052] By selecting an appropriate packaging material and adding micro-perforations, the carbon dioxide and oxygen transmission rates, i.e., β, of the package can be appropriately set to establish a CAP. Thus, with one or more perforations, the perforations can be adjusted to a carbon dioxide transmission rate, CO2TR, of the perforations. perf and oxygen transmission rate (O2TR) of perforations perf and thus, the carbon dioxide transmission rate CO2TR of the package is pack is the carbon dioxide permeability CO2TR of the perforation perf and the carbon dioxide transmission rate (CO2TR) of the packaging material, i.e., CO2TR pack =CO2TR perf +CO2TR mat and the oxygen transmission rate O2TR of the package. pack is the oxygen transmission rate O2TR of the perforation perf and the oxygen transmission rate O2TR of the packaging material, i.e., O2TR pack =O2TR perf +O2TR mat Therefore, the transmittance b of the packaging material pack b pack =(CO2TR perf +CO2TR mat ) / (O2TR perf +O2TR matAs mentioned above, the package according to the present disclosure has at least 1, 5, preferably at least 2, more preferably at least 3, even more preferably at least 4, e.g., 5 or more b pack has.

[0053] The packaging material has a capacity of at least 2000 ml / (m 2 .24 hours), preferably at least 3000 ml / (m 2 24 hours), more preferably at least 4000 ml / (m 2 24 hours), most preferably at least 5000 ml / (m 2 .24 hours), oxygen transmission rate (O2TR mat The oxygen transmission rate is measured according to ASTM D3985 2556 (coulometric method) at a test temperature of 23°C.

[0054] The packaging material has a capacity of at least 15000 ml / (m 2 24 hours), preferably at least 20,000 ml / (m 2 24 hours), more preferably at least 25000 ml / (m 2 24 hours), most preferably at least 30000 ml / (m 2 24 hours), carbon dioxide transmission rate (CO2TR mat The carbon dioxide permeability is measured according to ISO 2556 (manometric method) at a test temperature of 23°C.

[0055] A package according to the present disclosure may also be in the form of a tray and a lidding film sealed to the tray, thus closing the package, in which case the lidding film is a biaxially oriented polyethylene (BOPE) or unidirectionally oriented polyethylene (MDOPE) containing polymer film.

[0056] The tray packaging may protect the produce from mechanical damage and / or collect juices that leak from the produce and is therefore particularly suitable for soft and / or liquid producing produce, such as soft fruits, berries, grapes and / or flowers. Tray packaging made of a barrier material may be particularly robust for such purposes.

[0057] Produce packaged in such tray packages according to the present concepts may have an extended shelf life. The lidding film may be a preferred location for one or more perforations and may be particularly influential in determining the permeability of the package. For example, the lidding film may have a particular carbon dioxide and / or oxygen permeability of the packaging material.

[0058] Trays formed from sheet materials including one or more layers that include polyethylene terephthalate (PET) can be strong and lightweight. The packaging material is highly recyclable and reduces the environmental footprint. In such PET trays, the packaging material of each layer of the formed tray may include at least 50%, preferably at least 85%, more preferably at least 95% amorphous polyethylene terephthalate, which facilitates the formation of the tray and provides high transparency for the tray.

[0059] The package may comprise a peripheral sealing rim provided with a layer of adhesive along the circumference of the tray, preferably along the entire circumference of the tray, which may facilitate sealing of a lidding film of another (non-PET) material to the tray.

[0060] The present disclosure provides a method for manufacturing a package for preserving respiring produce contained within the package, the method comprising: i. providing a closed package defining a package volume for containing a portion of the respiring produce within the package volume from a packaging material comprising a biaxially oriented polyethylene (BOPE) or unidirectionally oriented polyethylene (MDOPE) containing polymeric film having a haze of 10 or less, preferably 5 or less, more preferably 3 or less, and most preferably 2 or less, as determined by ASTM D 1003; and ii. the package has a carbon dioxide transmission rate (COTR) of at least 1000 ml / 24 hours, preferably at least 1500 ml / 24 hours, more preferably at least 2000 ml / 24 hours, and most preferably at least 2500 ml / 24 hours per 100 grams of produce to be packaged; pack determining the size and possibly the number of perforations that are or are to be provided in the packaging material to allow gas exchange between the package atmosphere and the atmosphere surrounding the package, so as to form the package into a controlled atmosphere package (CAP); The present invention is further directed to the above method, comprising:

[0061] A suitable packaging material for this method has a capacity of at least 2000 ml / (m 2 .24 hours), preferably at least 3000 ml / (m 2 24 hours), more preferably at least 4000 ml / (m 2 24 hours), most preferably at least 5000 ml / (m 2 However, the oxygen transmission rate O2TR of the packaging material is preferably 15000 ml / (m 2 ) or less to facilitate adjustment using the one or more perforations. 2 .24 hours), more preferably less than 10,000 ml / (m 2 0.24 hours).

[0062] The preferred packaging material has a carbon dioxide transmission rate (CO2TR) of at least 10,000 ml / (m 2 .24 hours), preferably at least 12000 ml / (m 224 hours), more preferably at least 15000 ml / (m 2 24 hours), most preferably at least 20,000 ml / (m 2 However, the carbon dioxide transmission rate CO2TR of the packaging material may be 100,000 ml / (m 2 .24 hours) or less in order to facilitate adjustment using the one or more perforations. 2 24 hours), more preferably less than 75,000 ml / (m 2 0.24 hours).

[0063] A method of manufacturing a package for preserving respiring produce contained therein may also be directed to manufacturing a tray having a lidding film sealed to the tray, thus closing the package, wherein the lidding film is a biaxially oriented polyethylene (BOPE) or unidirectionally oriented polyethylene (MDOPE) containing polymer film.

[0064] The package containing the respiring produce may be closed manually using a closing device (e.g., a tie, clip, tape, elastic band, etc.) and / or by folding and / or by knotting. Additionally or alternatively, the package may be (further) closed by other techniques, for example by the use of adhesives and / or by welding, which may include using handheld devices and / or automated devices that may be provided on the apparatus. The package may be closed immediately after filling, or the produce may be filled into the package and the package closed after further processing and / or conditioning steps, for example after cooling.

[0065] It has been found that by using polymeric films containing BOPE or MDOPE, the amount of oxygen within the package can be reduced below that normally tolerated in CAPs that must tolerate a higher amount of oxygen than is desirable to prevent unacceptably high levels of CO2.

[0066] More importantly, such packages can extend the shelf life of respiring produce within the CAP package by several days, representing an increase in shelf life of 30-100% or more compared to conventionally used polymeric films.

[0067] More specifically, in CAP, the oxygen concentration in the package atmosphere may be reduced while ensuring a minimum level of oxygen in order to slow down aging processes. Additionally or alternatively, the carbon dioxide concentration in the package atmosphere may be controlled to ensure a level below that which would be harmful. Thus, aging, maturation and / or decay is slowed down, and in particular anaerobic processes, such as off-flavors, decay cell membrane breakdown, are prevented. In general, it is preferable to reach equilibrium oxygen and / or carbon dioxide concentrations as quickly as possible. For this purpose, a combination of CAP and MAP may be used. For MAP, an initial package atmosphere may be established at or near the time of closing the package by generating and / or introducing into the package volume an atmosphere modification gas or gas mixture different from the ambient atmosphere.

[0068] For long-term storage, most produce benefits from both low CO2 and low O2 concentrations in the package atmosphere, where the O2 concentration is in the range of about 1-10% by volume ("% vol"), preferably 3-7% vol. To maintain such low O2 concentrations, the one or more perforations in the package must provide an open area configured to control the inflow of oxygen into the package volume, in particular establishing a minimum inflow to prevent anaerobicity and a maximum inflow to ensure that low oxygen concentrations slow the metabolic processes of the produce (aka "putting the produce to sleep"). Given that the perforations are non-selective with respect to O2 and CO2, this restriction on the open area of ​​the one or more perforations essentially limits the egress of CO2 from the package through the perforations. Typically, the CO2:O2 flow ratio for one small laser perforation is approximately 1. Hence, the perforations in the package simultaneously determine an upper limit for the egress of CO2 and the ingress of O2. Thus, the manufacture of CAP packages imposes a compromise between increasing the outflow of desired CO2 on the one hand and increasing the inflow of undesired O2 on the other hand.

[0069] Therefore, a high CO2TR of the packaging material is beneficial in establishing an improved concentration balance between O2 and CO2 in the package atmosphere because it increases the permeability for CO2 throughout the CAP dressing.

[0070] The package atmosphere may define a balance amount of oxygen and carbon dioxide which together account for less than 20% by volume of the package atmosphere, preferably less than 17% by volume, such as less than 15% by volume or even less than 13% by volume.

[0071] As a rule of thumb, it has been found that in current packaging films for fresh, respiring produce, the combined amounts of O2 and CO2 in the CAP typically account for about 21 to about 23% by volume of the packaging atmosphere ({volume O2} + {volume CO2} = about 21 to about 23% by volume of the package atmosphere). In currently available packages, the permeability of the packages makes it easy to avoid the rule of thumb mentioned above and achieve both low concentrations of O2 and CO2 in the package atmosphere and low concentrations of CO2 in the combined concentrations.

[0072] Most aging processes result in the evolution of CO2, causing its accumulation in the packaging atmosphere. High CO2 concentrations can promote anaerobic decay processes and must be prevented. However, too high a carbon dioxide transmission rate can prevent the desired slowing down of metabolic processes and the associated increased shelf life. To achieve such a balance, the currently offered ranges are preferred.

[0073] Respiration and most aging processes result in the consumption of O2, causing a depletion in the packaging atmosphere. A high O2TR of the packaging material and / or a high carbon dioxide transmission rate CO2TR of the packaging material facilitates fine-tuning of the oxygen inflow and respectively the carbon dioxide outflow, for example by precisely establishing the ratio between the area of ​​the packaging material and the open area of ​​one or more perforations to achieve the transmission rate of the package.

[0074] The packaging volume may be in the range of 2-5 times the volume of the produce in the package, and in some cases may be in the range of 3-4 times the volume of the produce in the package. In some cases, the packaging volume may be in the range of 5-10 times the volume of the produce, such as 6-8 or 7 times. Larger volume ratios may be used, particularly for consumer packages, and / or for one or more produce that are hollow, delicate and finely divided, such as raspberries, cut lettuce, herbs (parsley stalks, thymian sprigs, etc.). The volume of the package not occupied by the produce is commonly referred to as the headspace.

[0075] The present disclosure is further illustrated by the following examples, which are merely illustrative and should not be construed as limiting.

[0076] Working Example

[0077] Examples 1 to 13

[0078] Several pouches of the claimed BOPE film were provided with produce. The BOPE film was a five-layer film and had the following properties: Thickness: 30 micrometers, Haze: 2.5 based on AST D 1003 Tensile strength: MD=80, HD=210 as determined according to AST D882 Density: 0.937g / cm 3 CO2TR: 30.000ml / (m2) when determined according to ISO 2556 at a test temperature of 23°C 2 .24 hours).

[0079] The results are given in Table I below.

[0080] Comparative Examples 14 to 26

[0081] For comparison, the shelf life after packaging of the same produce of similar size and volume in conventional polyethylene and BOPP pouches for food packaging was given, and the results are given in Table II below.

[0082] Examples 27-33 Quality and gas levels of 150g packaged spinach stored at 6°C

[0083] 150 g of spinach was packaged in perforated or non-perforated pouches (260 mm x 270 mm) and stored for 20 days at 6° C. On days 2, 6, 9, 14, 17 and 20, oxygen (O2) and carbon dioxide (CO2) levels in the pouches and overall quality were evaluated.

[0084] When BOPE pouches were used, the same film was used as in Examples 1-14 with a thickness of 40 micrometers. When BOPP pouches were used, the same material was used as in Examples 14-26 with a film thickness of 30 micrometers (CO2TR 3500ml / m2.24 hours) and an anti-fog coating was applied. Film thicknesses of 40 and 30 micrometers were found to be equivalent in terms of CO2TR and O2TR and could therefore be used interchangeably. Also, the relevance of oxygen flushing (10% residual O2) of the filled pouches was evaluated. Microperforations, if present, were applied by PerfoTec laser microperforation PER 30, and all pouches were applied with the same perforation pattern. To calculate the optimal microperforation pattern, the producer's respiration rate was previously determined using the Fast Respiration Meter System 4.0.

[0085] The results are summarized in Table III below.

[0086] These results show that spinach packaged in a BOPE according to the invention with perforations and a CO2TR per 100 g produce provides a shelf life of at least 20 days. The CO2 levels in these packages remained below 5% during the test period, while the O2 levels were maintained in the range of about 10%, which is optimal for this batch of spinach. CO2 levels above 5% are considered harmful because they affect the taste and odour of the produce. Positive results were obtained in both oxygen-flushed and non-flushed packages. Compared to the BOPP package (shelf life of 9 days), this is an increase of at least 222%.

[0087] However, all BOPP packages experienced an increase in CO2 early in the test period, with CO2 levels exceeding 5%, and when the BOPP packages were perforated, the CO2 levels rose rapidly, causing a deterioration in product quality, resulting in a shelf life of only 9 days.

[0088] Examples 34-39 Quality and gas levels of 80g packaged lamb's lettuce stored at 6°C

[0089] 80g of lamb's lettuce was packaged in pouches (260mm x 270mm) with or without perforations and stored at 6°C for 17 days. Oxygen (O2) and carbon dioxide (CO2) levels in the pouches and overall quality were evaluated on days 2, 6, 9, 14 and 17. Also, the relevance of oxygen flush (10% residual O2) of the filled pouches was evaluated. The BOPE and BOPP pouches had the same dimensions and perforation pattern (if any) and were of the same material as in Examples 27-33.

[0090] The results are summarized in Table IV below.

[0091] These results show that lamb's lettuce packaged in a BOPE according to the invention with perforations and a CO2TR per 100 g produce provides a shelf life of at least 17 days. The CO2 levels in these packages remained below 5% during the test period, while the O2 levels were maintained in the range of about 10%, which is optimal for this batch of lamb's lettuce. CO2 levels above 5% are considered harmful because they affect the taste and odour of the produce. Positive results were obtained in both oxygen-flushed and non-flushed packages. Compared to the BOPP package (shelf life of 6 days), this is an increase of at least 283%.

[0092] The BOPP packaging met the CO2TR requirement per 100g produce, but after 2 days the CO2 increased to over 5%. Also, when perforated BOPP packaging was provided, the CO2 levels increased to over 5% after the 9th day, which is an improvement compared to non-perforated BOPP packaging, but it was still not enough and yellowing and rotting occurred on the 9th day. Due to the deterioration of product quality, the shelf life with BOPP is at best 8 days.

[0093] Examples 40-45 Quality and gas levels of 150g packaged arugula stored at 6°C

[0094] 150 g of arugula was packaged in perforated and non-perforated pouches (260 mm x 270 mm) and stored at 6°C for 17 days. Oxygen (O2) and carbon dioxide (CO2) levels in the pouches and overall quality were evaluated on days 2, 6, 9, 14 and 17. Also, the relevance of oxygen flush (10% residual O2) of the filled pouches was evaluated. The BOPE and BOPP pouches had the same dimensions, perforation pattern and materials as in Examples 27-33.

[0095] The results are summarized in Table V below.

[0096] These results show that arugula packaged in a BOPE according to the invention with perforations and a CO2TR per 100 g produce provides a shelf life of at least 17 days. The CO2 levels in these packages remained below 5% during the test period, while the O2 levels were maintained in the optimum range of about 15% for this batch of arugula lettuce. CO2 levels above 5% are considered harmful because they affect the taste and smell of the produce. Positive results were obtained in both oxygen-flushed and non-flushed packages. Compared to the BOPP package (six-day shelf life), this is an increase of at least 283%.

[0097] The BOPP packaging showed a rise in CO2 above 5% after a few days. In addition to the harmful CO2 levels, the O2 levels were also not optimal, dropping to 0% over the test period. Also, when the BOPP packaging with perforations was provided, the CO2 levels rose to above 5% after the second day, and the O2 levels dropped less significantly, dropping to 0% by the 9th day, resulting in yellowing and spoilage. The resulting shelf life with BOPP is at best 8 days, due to the reduced product quality.

[0098] [Table 1]

[0099] [Table 2]

[0100] [Table 3]

[0101] [Table 4]

[0102] [Table 5]

Claims

1. 1. A package for preserving respiring produce contained within the package, the package defining a package volume and a package atmosphere for containing a portion of the produce, the package comprising: Packaging materials containing biaxially oriented polyethylene (BOPE) or unidirectionally oriented polyethylene (MDOPE)-containing polymer films having a haze of 10 or less as determined by ASTM D 1003 Including, wherein the polymer film is provided with one or more perforations that allow gas exchange with the atmosphere surrounding the package to form the package into a controlled atmosphere package (CAP); Here, the packaging body has a carbon dioxide permeability (CO 2 TR pack ) and Here, the carbon dioxide permeability (CO 2 TR pack ) is the carbon dioxide permeability (CO 2 TR perf ) and the carbon dioxide permeability (CO 2 TR mat ) and the sum of (CO 2 TR pack =CO 2 TR perf +CO 2 TR mat ) such that the one or more perforations have a carbon dioxide permeability (CO 2 TR perf ) and Here, the CO 2 TR pack is at least 1000 ml / 24 hours per 100 grams of produce to be packaged, The packaging.

2. 10. The package of claim 1, wherein the produce to be packaged is selected from fresh cut leafy greens, fresh cut vegetables, fresh fruit, herbs, flowers, or prepared salads.

3. 3. The package of claim 2, wherein the fresh-cut leafy greens comprise lettuce, arugula, spinach, romaine, or combinations thereof.

4. 3. The package of claim 2, wherein the fresh cut vegetables comprise kidney beans, zucchini, carrots, sprouts, leeks, cauliflower, broccoli, or combinations thereof.

5. The package of claim 2, wherein the fresh fruit comprises berries, apples, pears, tomatoes, peppers, bananas, stone fruits, or combinations thereof.

6. 3. The package of claim 2, wherein the prepared salad comprises fresh cut leafy greens and / or fresh cut vegetables and / or fresh fruit.

7. 3. The package according to claim 1, wherein the thickness of the polymer film layer is in the range of 5 to 200 micrometers.

8. The packaging material has an oxygen permeability (O 2 TR pack ) and oxygen permeability (O 2 TR perf ), and the packaging has an oxygen permeability (O 2 TR pack ) is the oxygen permeability (O 2 TR perf ) and the oxygen permeability (O 2 TR mat ) and the sum (O 2 TR pack =O 2 TR perf +O 2 TR mat ) and the permeability b pack But, b pack =(CO 2 TR perf +CO 2 TR mat ) / (O 2 TR perf +O 2 TR mat ) where the permeability b of the packaging material pack =CO 2 TR pack / O 2 TR pack 3. The package of claim 1, wherein the ρ is at least 1.

5.

9. The packaging material has a capacity of at least 2000 ml / (m 2 Oxygen permeability (O ) for 24 hours 2 TR mat 3. The package of claim 1 or 2, comprising:

10. The packaging material has a capacity of at least 15000 ml / (m 2 Carbon dioxide permeability (CO ) over 24 hours 2 TR mat 3. The package of claim 1 or 2, comprising:

11. 3. A package for preserving respiring produce contained within a package according to claim 1 or 2, wherein the packaging material comprises a tray and a lidding film sealed to the tray and thus closing the package; wherein the lid film is a polymer film containing biaxially oriented polyethylene (BOPE) or unidirectionally oriented polyethylene (MDOPE); The packaging for storing the product.

12. 1. A method for manufacturing a package for preserving respiring produce contained within the package, comprising: i. providing a closed package defining a package volume for containing a portion of the respiring produce within the package volume from a packaging material comprising a biaxially oriented polyethylene (BOPE) or unidirectionally oriented polyethylene (MDOPE)-containing polymeric film having a haze of 10 or less as determined by ASTM D 1003; and ii. The package has a carbon dioxide transmission rate (CO ) of at least 1000 ml / (m .24 hours) per 100 grams of produce to be packaged. 2 TR pack determining the size and possibly the number of perforations that are or are to be provided in the packaging material to allow gas exchange between the package atmosphere and the atmosphere surrounding the package, so as to form the package into a controlled atmosphere package (CAP); The method comprising:

13. The packaging material has a capacity of at least 10,000 ml / (m 2 Carbon dioxide permeability (CO ) over 24 hours 2 13. The method of claim 12, comprising:

14. The packaging material has a capacity of at least 2000 ml / (m 2 Oxygen permeability (O ) for 24 hours 2 14. The method of claim 12 or 13, comprising:

15. 14. A method of manufacturing a package for preserving respiring produce contained within the package of claim 12 or 13, wherein the packaging material comprises a tray and a lidding film sealed to the tray, thereby closing the package, and wherein the lidding film is a biaxially oriented polyethylene (BOPE) or unidirectionally oriented polyethylene (MDOPE) containing polymer film.