Extract, packaging material that contains said extract, its method of manufacturing and use thereof

Abstract

The present invention relates to a fermented lyophilised antioxidant extract and a packaging material comprising polycaprolactone (PCL) reinforced with the aforementioned fermented and encapsulated antioxidant extract derived from pineapple by-products. According to the invention, the extract is present in at least 10% of the total weight, forming a material with an antioxidant capacity of at least 115 mg Trolox / 100 g material. The present invention further relates to a method of manufacturing the extract and the packaging material including, among other steps, ultrasound-assisted extraction, fermenting the lyophilised pineapple extract, encapsulating it and extruding the capsules containing the lyophilised pineapple extract therein with PCL. Advantageously, the material obtained is used for packaging fatty foods in order to increase their shelf life.

Description

[0001] DESCRIPTION

[0002] Extract, packaging material containing said extract, its manufacturing process and use thereof.

[0003] FIELD OF INVENTION

[0004] Sector: Food packaging materials.

[0005] STATE OF THE PRIOR ART

[0006] Currently, there is a growing trend toward the utilization and revaluation of components obtained from biomass (lignocellulosic plants or industrial and agricultural waste), thus contributing to the management and revaluation of waste and environmental pollution. These byproducts are rich in various compounds of interest such as antioxidants, antimicrobials, dietary fibers, nanomaterials, and colorants, among others, as reflected in the works of Beltrán Sanahuja, A.; Ponce Landete, M.; Domingo Martínez, M.; Prats Moya, M.; Valdés García, A.: Optimization of Volatile Compounds Extraction from Industrial Celery (Apium graveolens) By-Products by Using Response Surface Methodology and Study of Their Potential as Antioxidant Sources (Foods 2021, 10, 2664. https: / / doi.org / 10.3390 / foods10112664) and Valdés A, Vidal L, Beltrán A, Canals A, Garrigós MC.: Microwave-Assisted Extraction of Phenolic Compounds from Almond Skin Byproducts (Prunus amygdalus): A Multivariate Analysis Approach (J Agrie Food Chem. 2015 Jun 10;63(22):5395-402. doi: 10.1021 / acs.jafc.5b01011. Epub 2015 May 29. PMID: 26005743).

[0007] Some approaches to its revaluation have focused on the development of new, more environmentally friendly packaging materials that allow food to be packaged in the best conditions to increase its shelf life, as indicated by Bangar S, Purewal S, Trif M, Maqsood S, Kumar M, Manjunatha V and Rusu A. in their work Functionality and Applicability of Starch-Based Films: An Eco-Friendly Approach (Foods. 2021, 10(9), 2181).

[0008] Consequently, and to avoid the use of petroleum-derived packaging materials, new biodegradable materials in the form of flexible film for food packaging have been developed and tested in recent decades.

[0009] In addition to environmentally sustainable packaging, the latest research trend focuses on the development of materials with antifungal, antimicrobial, and antioxidant properties, among others. The latter are very promising alternatives for extending the shelf life of high-fat foods.

[0010] In this sense, ethanolic or aqueous extracts of plant residues can be an interesting source of antioxidant substances. For this reason, several studies have recently been conducted using fruit residues for this purpose.

[0011] In this context, pineapple is a good option since global production is quite high, around 28 million tons per year. The pineapple processing industry generates a large amount of waste and byproducts, such as the pulp, core, peel, and crown. To date, pineapple waste and byproducts have been used as a source of bromelain, carbohydrates, essential oils, and polyphenols, among other applications. Some studies have demonstrated the potential of using pineapple as a source of antioxidant compounds in general and, more specifically, its richness in certain polyphenols.

[0012] Following this line, catechin, ferulic acid, gallic acid and epicatechin have been described as abundant polyphenols in pineapple residues and by-products, as reported in the work by Li T, Shen P, Liu W, et al. “Major polyphenolics in pineapple peels and their antioxidant interactions" (Int J Food Prop. 2014;17(8):1805- 1817. doi:10.1080 / 10942912.2012.7321686).

[0013] Related to the incorporation of the aforementioned extracts into packaging materials, in this sector, microcapsules are used to protect the active compounds from high processing temperatures, reduce their degradation and control the release of active agents from the packaging itself to the food during the time it is packaged (aromas, antioxidants, antimicrobials, flavors, colorants...) and for this purpose, different techniques are used, among which the spray-drying technique stands out. Regarding the application of the spray-drying technique in antioxidants obtained from pineapple by-products, Lourengo and his team [VD 2021. Optimization of natural antioxidants extraction from pineapple peel and their stabilization by spray drying. Foods, 10, doi:10.3390 / foods10061255] carried out a solid-liquid extraction of the pineapple peel, using a sample / extraction solvent ratio of 1 / 1 (w / w), at room temperature for 25 min using a mixture of ethanol / water (80 / 20) as the extraction solvent. Under these conditions, the resulting extract showed a total polyphenol content (TPC) of 11.10 ± 0.01 mg gallic acid equivalent (GAE) / g dry extract, antioxidant activity of 91.79 ± 1.98 pmol Trolox / g dry extract by the DPPH method and 174.50 ± 9.98 pmol Trolox / g dry extract by the FRAP (Ferric Reducing Antioxidant Power) method. The antioxidant-rich extract was subjected to stabilization by spray-drying process at 150 °C inlet air temperature using maltodextrin (5% w / w) as an encapsulating agent. The results showed that the antioxidant capacity of the encapsulated compounds was maintained after encapsulation.

[0014] Once the active compounds have been stabilized, in order to develop a package, they are incorporated into materials that can be biopolymeric using conventional techniques used in the packaging sector, such as extrusion processing, in order to subsequently transfer the developed technology to an industrial level. Various biopolymers can be used as polymeric matrices, such as (Polycaprolactone (PCL), Polylactic acid (PLA) with different L / D-lactide ratios, polyhydroxyalkanoates (PHAs), cellulose derivatives and mixtures between them.

[0015] In the specific case of the incorporation of antioxidants from pineapple into biopolymeric matrices, it is worth highlighting the work carried out by Lourengo et al. (VD2020. Application of edible alginate films with pineapple peel active compounds on beef meat preservation. Antioxidants, 9, 1-15, doi:10.3390 / antiox9080667), in which alginate-based films containing natural antioxidants from pineapple peel were developed. These active materials have been applied to control microbiological degradation, preserve color, and act as a barrier to lipid oxidation in beef steaks stored at 4°C for 4 days. Prior to their incorporation into the biopolymeric matrix, the compounds extracted in a hydroalcoholic solvent are stabilized by spray-drying. The bioactive films display greater antioxidant activity than the control materials.Furthermore, pineapple waste is rich in cellulose, lignin, pectin, and their derivatives, making it a suitable material for developing biodegradable packaging. Rodsamran and Sothornvit evaluated the use of pineapple peel as a natural plasticizer for the production of edible films in their work “Preparation and characterization of pectin fraction from pineapple peel as a natural plasticizer and material for biopolymer film” (R. 2019. Food Bioprod Process, 118, 198–206, doi: 10.1016 / j.fbp.2O19.09.010).

[0016] An increase in the amount of pineapple peel extract rich in pectin and polyphenols increased the TPC value, also providing antioxidant capacity to the developed film. In another study carried out by Kumar (KK 2021. “Pineapple peel extract incorporated poly(vinyl alcohol)-corn starch film for active food packaging: Preparation, characterization and antioxidant activity'. Int J Biol Macromol, 187, 223- 231 , doi:10.1016 / j.ijbiomac.2021.07.136), pineapple peel extract was incorporated as a natural antioxidant to produce polyvinyl alcohol-starch (PVA) films, obtaining improved thermal and antioxidant properties in the developed materials.

[0017] Furthermore, cellulose extracted from pineapple leaves has been used as a reinforcing agent in PLA, improving the material's tensile strength. Furthermore, the fermentation of byproducts and waste by selective bacteria can produce bioplastics commonly called polyhydroxyalkanoates (PHAs). PHAs are bio-based plastics and are biodegradable. Along these lines, Suwannasing and his team confirmed that waste from the pineapple processing industry can be used to produce PHAs.

[0018] All these studies highlight the potential of pineapple byproducts in the development of packaging materials, although further progress is needed in this line of research to improve the properties of the materials developed.

[0019] On the other hand, it is worth mentioning patents such as US64478261 B1 , CN106674575A, US10723536B2 and US2012276357A1 , among others, which disclose food packaging materials that provide antioxidant capacity to maintain and / or extend the shelf life of the food contained. However, none of said disclosed materials includes a pineapple extract reinforcement in their composition. Based on the above, the present invention seeks to solve the following problems:

[0020] 1. The revaluation of pineapple waste and by-products, promoting the circular economy.

[0021] 2. Increased shelf life of fatty foods due to the fact that, through the antioxidant active packaging material developed based on polycaprolactone (PCL), it allows delaying and / or avoiding oxidative degradation reactions in foods.

[0022] Therefore, this patent application describes a product that represents a new application for pineapple waste and by-products, through the extraction of antioxidant compounds and their use as additives to packaging materials to increase the shelf life of packaged fatty foods.

[0023] EXPLANATION OF THE INVENTION

[0024] The present invention relates to an extract from a natural source and packaging material incorporating said extract into its formulation.

[0025] So the extract is freeze-dried and fermented, comes from pineapple by-products and is made up of the following composition:

[0026] - between 600 and 1800 mg of succinic acid per 100 g of fermented freeze-dried pineapple extract,

[0027] - between 0.03 and 0.09 mg of gallic acid per 100g of fermented freeze-dried pineapple extract,

[0028] - between 0.6 and 1.8 mg of syringic acid per 100g of fermented freeze-dried pineapple extract,

[0029] - between 0.04 and 0.12 mg of coumaric acid per 100 g of fermented freeze-dried pineapple extract, and

[0030] - between 0.225 and 0.680 mg of ferulic acid per 100g of fermented freeze-dried pineapple extract, thus the extract is an antioxidant with a total polyphenol content (TPC) of at least 2245 mg Trolox per 100g of fermented freeze-dried pineapple extract.

[0031] Thus, the packaging material includes polycaprolactone (PCL) as a base biopolymer reinforced with the previously fermented and encapsulated antioxidant extract from pineapple by-products, where the extract is present in at least 10% of its total weight, constituting a material with a total polyphenol content (TPC) of at least 115 mg Trolox / 100g material. Likewise, the object of the present invention is the process for manufacturing the extract and the packaging material obtained from said extract, as well as the use of the obtained material in the packaging of fatty foods in order to increase their shelf life.

[0032] In this sense, pineapple by-products are understood to be those parts of the pineapple that are not used for consumption and are considered waste or leftovers to be discarded.

[0033] The pineapple by-products preferably used in the packaging material of the present invention are pineapple stems. Thus, the packaging material is preferably transparent, formed from a flexible film, and has a thickness between 0.080 mm and 0.120 mm.

[0034] In essence, the manufacturing process of the packaging material developed proposes:

[0035] Obtaining, purifying and stabilizing an antioxidant extract from pineapple by-products;

[0036] The extrusion of the antioxidant extract obtained into a PCL matrix to produce an active packaging material, flexible film type, with antioxidant capacity.

[0037] In this sense, the manufacturing process of the extract of the present invention consists of the following steps:

[0038] Grinding of the frozen pineapple by-product and dehydration of the ground product at a temperature between 25°C and 40°C for at least 48 hours.

[0039] - Addition of an aqueous ethanol solution with a concentration of at least 50% to the ground and dehydrated pineapple by-product obtained in the previous stage.

[0040] Ultrasound-assisted extraction, preferably using a sonotrode, applying an amplitude of at least 65% and maintaining the temperature below 45°C. For example, applying an extraction time of 5 minutes and at least two cycles maintains the temperature below 45°C.

[0041] Centrifugation of the pineapple by-product. Optionally, this centrifugation is carried out for at least 10 minutes at a speed of at least 4000 rpm.

[0042] Recovery of the supernatant corresponding to the pineapple extract, Elimination of ethanol contained in the supernatant by applying vacuum and a maximum temperature of 40°C, obtaining the pineapple extract.

[0043] - Addition of fresh yeast to pineapple extract.

[0044] Fermentation by stirring the solution obtained in the previous step in a closed system at a temperature between 32°C and 37°C for at least 3 days. It should be noted that a closed system refers to, for example, a covered reactor. Optionally, agitation of at least 200 rpm is applied during fermentation.

[0045] Filtering the solution, removing yeast residues, obtaining a solution of fermented pineapple extract.

[0046] Freezing of the fermented pineapple extract solution at a temperature less than or equal to -20°C.

[0047] Lyophilization and production of a freeze-dried pineapple extract in powder form. Preferably, lyophilization is carried out at a temperature between -55°C and -35°C and a pressure between 0.200 and 0.5 mbar for approximately 48 hours.

[0048] Thus, the ultrasound-assisted extraction has a yield of at least 45% and the freeze-dried pineapple extract obtained is antioxidant, fermented, and has a total polyphenol content (TPC) of at least 2245 mg Trolox per 100g of fermented freeze-dried pineapple extract.

[0049] Optionally, after the freeze-drying stage through which the fermented freeze-dried pineapple extract is obtained, the following steps are carried out to obtain a packaging material:

[0050] Dispersion of an encapsulating agent solution together with the freeze-dried pineapple extract, and spray-drying using an air stream at a temperature greater than 100°C, obtaining solid capsules containing the freeze-dried pineapple extract inside. Thus, the resulting encapsulation is stable against temperature degradation. Extrusion of the solid capsules containing the freeze-dried pineapple extract with PCL to obtain a packaging material. Preferably, the extrusion is carried out at least at 60°C and with pressures and injection times of 4 - 4 - 4 bar and 1 - 0.05 - 4 s, respectively.

[0051] Thus, the freeze-dried pineapple extract is present in at least 10% of the packaging material, while the packaging material obtained has a significantly higher antioxidant capacity, at least 3 times higher, than a material obtained based on PCL, but incorporating unfermented pineapple extract in its formulation.

[0052] It should be noted that glycerol (or a similar agent such as sorbitol) may also be used in the dispersion of the encapsulating agent solution along with the freeze-dried pineapple extract. Whether with or without glycerol, in one embodiment of the invention—as detailed below—the encapsulating agent is a milk protein.

[0053] Advantageously, the use of pineapple by-products in packaging material enables the reuse of such waste, while the use of this material extends the shelf life of fatty foods thanks to its ability to delay and / or prevent oxidative degradation reactions.

[0054] Thus, the packaging material of the present invention preferably has a form of flexible antioxidant film.

[0055] BRIEF DESCRIPTION OF THE FIGURES

[0056] To complement the description being made and in order to help better understand the characteristics of the invention, a set of figures is attached as an integral part of said description, in which the following has been represented for illustrative and non-limiting purposes:

[0057] Figure 1 shows the infrared spectrum (FTIR) of freeze-dried pineapple extract.

[0058] Figure 2 shows the thermogravimetric analysis (TGA) of the freeze-dried pineapple extract.

[0059] Figure 3 shows the FTIR spectrum of the fermented freeze-dried pineapple extract.

[0060] Figure 4 shows the FTIR spectrum of commercial whey protein.

[0061] Figures 5 and 6 show the FTIR spectra of the capsules with unfermented freeze-dried pineapple extract and the capsules with fermented freeze-dried pineapple extract, respectively.

[0062] Figure 7 shows the PCL materials with 10% fermented freeze-dried pineapple extract.

[0063] Figure 8 shows the spectrum of a control material of PCL CAPA 6500.

[0064] Figure 9 corresponds to the FTIR spectrum of the PCL CAPA 6500 material + 10% unfermented freeze-dried pineapple extract.

[0065] Figure 10 corresponds to the FTIR spectrum of the PCL CAPA 6500 material + 15% unfermented freeze-dried pineapple extract.

[0066] Figure 11 corresponds to the FTIR spectrum of the PCL CAPA 6500 material + 10% fermented freeze-dried pineapple extract.

[0067] Figure 12 corresponds to the FTIR spectrum of the PCL CAPA 6500 material + 15% fermented freeze-dried pineapple extract.

[0068] Figure 13 shows the thermogravimetric analysis of a control material of PCL CAPA 6500.

[0069] Figure 14 corresponds to the thermogravimetric analysis of the PCL CAPA 6500 material + 10% unfermented freeze-dried pineapple extract.

[0070] Figure 15 corresponds to the thermogravimetric analysis of the PCL CAPA 6500 material + 15% unfermented freeze-dried pineapple extract.

[0071] Figures 16, 17 and 18 show the FTIR spectra of a PCL flexible film material including 5, 10 and 15% of unfermented freeze-dried pineapple extract capsules, respectively.

[0072] Figures 19, 20 and 21 correspond to the thermograms of the PCL materials with 5, 10 and 15% of capsules with unfermented pineapple extract.

[0073] Figures 22, 23 and 24 show the FTIR spectra of the materials prepared and tested in Figures 19, 20 and 21, respectively.

[0074] Figures 25 and 26 show the thermograms of PCL materials with 10% and 15% capsules with fermented pineapple extract, respectively.

[0075] PREFERRED EMBODIMENT OF THE INVENTION

[0076] The following tests are detailed, which illustrate the competitive advantage of the material developed in the present invention.

[0077] Experimental procedure 1. Obtaining antioxidant active extracts from pineapple by-products.

[0078] The conventional extraction method used was adapted from Valdés García et al [detailed in Potential of Industrial Pineapple (Ananas Comosus (L.) Merrill) By-Products as Aromatic and Antioxidant Sources. Antioxidants 10, no 11 (November 4, 2021): 1767. https: / / doi.org / 10.3390 / antiox10111767].

[0079] First, to carry out the extraction using the conventional method, a sample of frozen pineapple core is taken, ground and dehydrated, keeping the sample at 40°C for 48 hours.

[0080] After this, place 2g ± 0.1g of ground and dehydrated pineapple in a test tube and add 4 mL of 50% aqueous ethanol solution.

[0081] The extract can be prepared using the ultrasound-assisted extraction (UAE) technique. To do this, weigh 1.5 g of dehydrated crushed pineapple and add a total volume of 13 mL of solvent (50% aqueous ethanol solution by weight) to the extraction tube.

[0082] Extraction is then carried out in the sonotrode using different conditions in order to obtain the optimal extraction conditions.

[0083] Table 1 shows the results of the experimental test used for the optimization of the extraction process, where the variables of amplitude (%), cycles and extraction time (minutes) are analyzed.

[0084] The experiments are generated in random order to avoid bias in the results and 5 central points are carried out (t = 10 minutes, C = 05:05, A = 45%).

[0085] To validate the experimental design, the total polyphenol content (TPC) and antioxidant capacity values ​​measured by the following two methods were used as a response: ABTS (2,2'-azino-bis-(3-ethylthiazoline-benzenesulfonic acid-6) and FRAP (Ferric Reducing Antioxidant Power).

[0086] The results shown in Table 1 indicate the TPC and antioxidant capacity values ​​measured by the two methods cited (ABTS and FRAP) for the extracts obtained using ultrasound-assisted extraction (UAE) under different conditions. It should be noted that UAE is an advantageous method compared to other conventional extraction methods, as it allows for industrial scaling.

[0087] Table 1 Mean TPC Mean FRAP Mean ABTS / , , ,

[0088] The optimal ultrasonic extraction conditions obtained with each method are shown in Table 2, which shows the optimal values ​​for each method (i.e., TPC, FRAP, and ABTS), separately and the combination of the three responses, and their correlation coefficient for the ultrasonic-assisted extraction results.

[0089] Table 2

[0090] TPC+FRAP+ABTS TPC FRAP ABTS

[0091] Optimal amplitude (%) 70.0 69.999 69.9336 70.0

[0092] Optimal cycles 2 7.0 3.60689 7.0

[0093] Optimal time (min) 5 15.0 5.29869 15.0

[0094] Correlation coefficient (%) 82.53 1ÓÓ 100 84.13 After carrying out the experiments, the optimal conditions obtained for ultrasound-assisted extraction using the sonotron are: Amplitude: 70 %; Cycles: 2 and Extraction time: 5 min.

[0095] Under these optimal conditions, ultrasound-assisted sample extraction is carried out in triplicate and the temperature is recorded at the end of each extraction.

[0096] Subsequently, a centrifuge tube is taken and the pineapple extract and the volume of ethanol from the sonotrode extraction tube are transferred.

[0097] The sonotrode extraction tube is washed with 1 ml of aqueous ethanol solvent and this volume is added to the centrifuge tube. The tubes are equilibrated and centrifuged for 15 minutes at 4500 rpm. Once centrifuged, the supernatant is stored and transferred to a rotary evaporator with a 40°C bath to eliminate the ethanol present in the solution. Once this solvent is removed, the aqueous extract is transferred to the lyophilizer vessels. They are frozen at -20°C and transferred to the lyophilizer at -55°C and 0.200 mbar for approximately 48 hours.

[0098] Finally, the powder extract must be stored in a freezer at a temperature of -21°C. The extraction yield obtained was (45.1 ± 1.7) %.

[0099] The relevant parameter in ultrasonic extraction is the amplitude applied, with maintaining the temperature below 45°C being vital. To maintain this temperature, for example, an extraction time of 5 minutes and at least two cycles are used.

[0100] The analysis of the composition of the mineral fraction in the freeze-dried pineapple extract samples obtained using the optimal conditions described previously was carried out using the Inductively Coupled Plasma Mass Spectrometry (ICP-MS) technique.

[0101] To do this, the sample is first digested using a microwave oven. 0.5 g of the sample, 7 mL of 65% HNO3 solution, and 1 mL of 30% H2O2 solution are added to the digester tube. In this case, four additional tubes containing water but no sample (blanks) were prepared. The digestion was carried out in 15 min, starting from an initial temperature of 200°C to a final temperature of 110°C, with a pressure of 45 bar and maximum power (1500 W for Ethos and 1200 W for starter units). The sample was then brought to a final weight of 20 g with distilled water. Once the digestion process was complete, both the blanks and the samples were filtered through a 0.23 pm filter and introduced into the ICP-MS.

[0102] The mean concentration values ​​of elements found in the prepared freeze-dried pineapple extract samples are shown in Table 3. Table 3. Composition expressed in mg element / 100 g freeze-dried extract (x ± SD; n=6). mg / 100 g freeze-dried extract

[0103] 11 B 1 ,51 ± 0.06

[0104] 23 Na 4.65 ± 0.15

[0105] 24 Mg 144 ± 5

[0106] 28 S¡ 41 ,6 ± 1 ,9

[0107] 31 P 71 ,8 ± 1 ,4

[0108] 32 S 81 ,9 ± 1 ,1

[0109] 39 K 1635 ± 52

[0110] 44 Ca 10.2 ± 0.3

[0111] 55 Mn 11 ,9 ± 0.4

[0112] 56 Fe 0.9 ± 0.6

[0113] 63 Cu 0.64 ± 0.03

[0114] 66 Zn 0.496 ± 0.018

[0115] 85 Rb 1 .66 ± 0.06

[0116] 88 Sr 0.144 ± 0.005

[0117] 95 Mo 0.0011 ± 0.0002

[0118] 137 Ba 0.0282 ± 0.0011

[0119] In addition, the main phenolic compounds were qualified by HPLC-MS (high performance liquid chromatography coupled to a mass spectrometer) using the following methodology:

[0120] The analysis of individual polyphenols in the samples was carried out by UHPLC-MS / MS using a commercial Agilent 1290 Infinity UHPLC system coupled to an Agilent 6490 triple quadrupole mass spectrometer (Santa Clara, CA, USA) with an Agilent Jet Stream ion source in Negative Ionization (NI) mode.

[0121] The separation of analytes was performed on an Agilent Poroshell 120 EC-C18 column (Agilent Technologies, Santa Clara, CA 95051-7201, USA), 3 x 100 mm, 2.7 pm, which was maintained at 25°C during the analysis. Under optimized conditions, the mobile phase consisted of solvent A (100.0% water + 0.1% formic acid) and solvent B (100.0% acetonitrile + 0.1% formic acid) using the following gradient: 5 min, 50% A and 50% B; 5.5 min, 80% A and 20% B; 6 min, 80% A and 20% B; 7 min, 10% A and 90% B; at a constant flow rate of 0.4 ml min. -1 For all samples, the injection volume was 1 pL.

[0122] Multiple reaction monitoring (MRM) analysis mode was used to monitor the transitions from precursor ions to dominant product ions. The optimized source parameters were as follows:

[0123] Positive:

[0124] Gas curtain temperature 275 °C, gas flow 11 L min -1, nebulizer pressure 40 psi, capillary voltage 3500 V; cell acceleration voltage 4 V; fragmentation voltage 380 V; residence time ranged from 10 to 40 ms depending on the compound being analyzed; first and second quadrupole resolution 0.7 (unit).

[0125] Negative:

[0126] Gas curtain temperature 275 °C, gas flow 11 L min -1 , nebulizer pressure 40 psi, capillary voltage 2800 V; cell acceleration voltage 4 V; fragmentation voltage 380 V; residence time ranged from 10 to 40 ms depending on the compound being analyzed; first and second quadrupole resolution 0.7 (unit).

[0127] Various specific transitions were used to determine each compound, and for each transition, the applied collision energy was optimized to detect the highest possible intensity.

[0128] A MassHunter workstation (version B.07.01) was used for data acquisition. MassHunter qualitative analysis (version B.07.00) and quantitative analysis software (version B.07.00) were used for data processing. The most abundant MRM transitions for each analyte were selected as quantifiers, and the other transitions were selected as qualifier ions. Calibration curves were run in the concentration range of 50 to 0.0055 mg kg -1 .

[0129] The results obtained from the concentration (expressed in mg compound / 100 g lyophilized pineapple extract) of succinic acid, gallic acid, syringic acid, coumaric acid and ferulic acid are those shown in table 4:

[0130] Table 4 mg compound / 100g Value Deviation freeze-dried pineapple extract Standard medium

[0131] 1 .19 Succinic acid 1 .19 1 .198 0.014

[0132] 1,21

[0133] 0.03 Gallic acid 0.03 0.030 0.002

[0134] 0.03

[0135] 0.25 Syringic acid 0.30 0.289 0.030

[0136] 0.31

[0137] 0.08 Cumaculate acid 0.08 0.0840 0.0003

[0138] 0.08

[0139] 0.25 Ferulic acid 0.24 0.245 0.003

[0140] 0.24

[0141] Figure 1 shows the FTIR spectrum (an acronym for “Fourier Transform Infrared Spectroscopy”) of the freeze-dried pineapple extract, where the abscissa axis corresponds to the wave number (expressed in cm -1 ) and the ordinate axis corresponds to the absorption intensity:

[0142] Figure 1 identifies the main absorption bands, which correspond to the following functional groups:

[0143] 800-1400 cm -1 : Bending or stretching stresses of carbohydrates

[0144] 900-1150 cm -1: Stretch tension C-0 and CC

[0145] 1200-1400 cm -1 : Vibrational bending OCH, CCH, COH of carbohydrates

[0146] 600-900 cm -1 : fingerprints with vibrational deformation of the CH or CH2 group.

[0147] 500-750 cm -1 : bending vibrations =CH or bending vibrations CC

[0148] 700-720 cm -1 : Pigments (B-carotene) 1338.5 cm -1 : C-OH Holocellulose

[0149] 1026.9 cm -1 : C-0 and OH stretching tensions of the ether and hydroxyl groups of polysaccharides

[0150] 1234.2; 1341.2, 1414.5 cm -1 : Lignin; Vibrational bending stresses OCH, CCH, COH of carbohydrates.

[0151] 3000-3600 cm -1 : Vibration and stretching stresses OH

[0152] 3300-3400 cm -1 : NH stretching tensions

[0153] 2920-3100 cm -1: =CH; -CH; CH2 Aliphatic Carbons

[0154] 1452.1 cm -1 : aromatic compounds

[0155] 1593.9 cm -1 : Stretching stresses C=O, C=C

[0156] 1714.4 cm -1 : C=O stretching of acetyl groups, hemicellulose uranic ester or ester bond of carboxylic groups of ferulic and p-coumaric acid of lignin (carboxylic acids, alcohols and phenols)

[0157] 1600.2 cm -1 : Amides

[0158] Figure 2 shows the thermogravimetric analysis (TGA) of the freeze-dried extract, with temperature (in °C) represented on the abscissa axis and mass (in %) on the ordinate axis, while the secondary ordinate (right) represents the first derivative DTG (in % / min). Figure 2 shows a peak around 200°C, corresponding to the temperature at which maximum degradation of the extract occurs, indicating that the extract is not thermally stable above 200°C.

[0159] In addition, a shelf-life study was carried out on freeze-dried pineapple extract, vacuum-packed under refrigeration, determining its antioxidant capacity using the FRAP method to verify whether the antioxidant capacity is maintained during vacuum-packed storage under refrigeration.

[0160] The results obtained are collected in Table 5, which indicates the antioxidant capacity, expressed in mg Trolox / 100 g freeze-dried pineapple extract.

[0161] Table 5

[0162] Month 1 Month 3 Month 4 Month 5 Month 7 Month 8 Month 9 mg Trolox /

[0163] 100g 1022 ± 65 968 ± 12 1059 ± 41 997 ± 45 1031 ± 13 1080 ± 15 1047 ± 12 additive From the data obtained it is confirmed that the antioxidant capacity is maintained for at least 9 months after the preparation of the freeze-dried pineapple extract and preserved under vacuum in refrigeration.

[0164] Finally, the total sugar content of the freeze-dried extract was determined. The average value was 2.084 mg of glucose / g of freeze-dried extract, with a Brix percentage of approximately 9.5–10.0%.

[0165] Purification of the freeze-dried extract obtained from pineapple by-products

[0166] To purify the pineapple extract, fermentation was carried out. Fresh Levital yeast (2 g per 150 mL of extract) was added to the freeze-dried pineapple extract obtained after the ethanol removal process using a rotary evaporator. The yeast was stirred with magnetic stirrer at 200 rpm at 32-37°C for 3 days. The vessel containing the solution was covered with aluminum foil to prevent the polyphenols from being degraded by light; in other words, the fermentation was carried out in a closed system.

[0167] After three days, the Brix percentage was measured to evaluate the amount of sugars present in the solution, obtaining a percentage of 3.0-3.5%. The initial Brix percentage was 9.5-10.0%, confirming that the fermentation had significantly reduced the sugar concentration.

[0168] The solution was vacuum filtered to remove yeast residues, frozen and lyophilized preferably by applying a temperature of -55°C and a pressure of 0.200 mbar for approximately 48 hours to obtain the lyophilized dry extract.

[0169] Four methods were performed to evaluate the total polyphenol content and antioxidant capacity and the results are shown in Table 6. In this sense, DPPH corresponds to another method for determining antioxidant capacity (2,2-diphenyl-1-picrylhydrazyl radical).

[0170] Table 6. TPC and antioxidant capacity data of 3 samples of freeze-dried fermented extract (expressed as mg gallic acid or Trolox / 100g freeze-dried fermented extract) from samples 1, 2 and 3 [The extraction was carried out by ultrasound applying the optimal conditions obtained previously: Amplitude 70%, time: 5 minutes and number of cycles = 2)]; and the comparison with the values ​​for the unfermented freeze-dried extract (sample 4).

[0171] TPC FRAP ABTS DPPH

[0172] Fermented extract 3 562 ± 15 or 4838 ± 21 5783 ± 217 3698 ± 127 lyophilized, sample 1

[0173] Fermented extract 2245 46 2860 336 4309 47 3097 2g7 freeze-dried, sample 2

[0174] Fermented extract 2873 ± 59 3375 ± 13 3223 ± 387 3527 ± 186 lyophilized, sample 3

[0175] Freeze-dried extract without 924 ± 751496 ± 25 1307 ± 27 1047 ± 24 ferment, sample 4 As can be seen, both the antioxidant capacity, measured by FRAP, ABTS and DPPH, and the total polyphenol content (TPC) are approximately three times higher in the samples in which the fermentation process is carried out (samples 1, 2 and 3). The main phenolic acids were also analyzed in the freeze-dried fermented pineapple extract, obtaining the results shown below in Table 7:

[0176] Table 7: Concentration (mg compound / 100 g fermented freeze-dried pineapple extract) of succinic acid, gallic acid, syringic acid, coumaric acid and ferulic acid. mg compound / 100 g fermented freeze-dried pineapple extract

[0177] 1136.77

[0178] Succinic acid 1124.85 1120 20

[0179] 1097.96

[0180] 0.06

[0181] Gallic acid 0.06 0.063 0.002

[0182] 0.06

[0183] 1 ,17 Syringic acid 1 ,14 1 ,201 0,079

[0184] 1,29

[0185] 0.08

[0186] Cuminic acid 0.08 0.0800 0.0013

[0187] 0.08

[0188] 0.44

[0189] Ferulic acid 0.45 0.451 0.009

[0190] 0.46

[0191] Figure 3 shows the FTIR spectrum of the fermented freeze-dried pineapple extract, where the abscissa axis corresponds to the wave number (expressed in cm -1 ) and the ordinate axis corresponds to the absorption intensity.

[0192] Figure 3 identifies the main absorption bands, which correspond to the following functional groups:

[0193] 800-1400 cm -1 : Bending or stretching stresses of carbohydrates

[0194] 900-1150 cm -1 : Stretch tension C-0 and CC

[0195] 1200-1400 cm -1: Vibrational bending OCH, CCH, COH of carbohydrates

[0196] 600-900 cm -1 : fingerprints with vibrational deformation of the CH or CH2 group.

[0197] 500-750 cm -1 : bending vibrations =CH or bending vibrations CC

[0198] 700-720 cm -1 : Pigments (B-carotene)

[0199] 1338.5 cm -1 : C-OH Holocellulose

[0200] 1026.9 cm -1 : C-0 and OH stretching tensions of the ether and hydroxyl groups of polysaccharides

[0201] 1234.2; 1341.2, 1414.5 cm -1 : Lignin; Vibrational bending stresses OCH, CCH, COH of carbohydrates.

[0202] 3000-3600 cm-1 : Vibration and stretching stresses OH

[0203] 3300-3400 cm-1 : NH stretching tensions 2920-3100 cm-1 : =CH; -CH; CH2 Aliphatic carbons

[0204] 1452.1 cm -1 : aromatic compounds

[0205] 1593.9 cm -1 : Stretching stresses C=O, C=C

[0206] 1712.5 cm -1 : C=O stretching of acetyl groups, uranium esters of hemicellulose, or ester bonds of carboxylic groups of ferulic and p-coumaric acid of lignin (carboxylic acids, alcohols, and phenols). This band is larger in the fermented extract compared to the unfermented extract, confirming the greater presence of phenolic groups, as observed in the antioxidant capacity data.

[0207] 1585.2 cm -1 : Amides

[0208] Stabilization of freeze-dried extract obtained from pineapple by-products

[0209] In order to encapsulate the lyophilized extract to stabilize it and protect it from temperature degradation, commercial whey protein, ISOPURE brand (flavorless) was used as an encapsulating agent, adding 10% glycerol to each formulation generated in order to reinforce the encapsulating agent.

[0210] Figure 4 shows the FTIR spectrum of the commercial whey protein used, where the abscissa axis corresponds to the wave number (expressed in cm -1 ) and the ordinate axis corresponds to the absorption intensity.

[0211] Thus, in Figure 4 the main absorption bands are identified, which correspond to the following functional groups:

[0212] 1513.8 cm -1 : Amide II (5 NH-, v CN) Peptide bond (CO-NH)

[0213] 1630.5 cm -1 : Amide I (v C=O-, v CN) Peptide bond (CO-NH) 1630.5cm' 1: primary amide region of serum proteins

[0214] 2928.4 cm -1 : stretching vibrations of the CH-CH2 and CH-CH3 bonding groups of fatty acids present in dairy products.

[0215] 1200-1700 cm -1 : vibrations of fatty acids, proteins and polysaccharides.

[0216] Three dispersions (P1, P2 and P3) were formulated, formed by the freeze-dried pineapple extract, prepared as previously indicated, at different concentrations of the encapsulating agent (milk protein, called WPI) as shown in Table 8. In all cases, a fixed value of 5% w / v of freeze-dried pineapple extract and the amount of glycerol added (10%) were added.

[0217] Table 8. Composition of the different formulations tested for the stabilization of freeze-dried pineapple extract.

[0218] Treatment Freeze-dried extract WPI

[0219] P1 5% w / v 3% w / v

[0220] P2 5% w / v 6% w / v

[0221] P3 5% w / v 12% w / v

[0222] *WPI: Whey protein

[0223] *10% w / v Glycerol was added to all dispersions

[0224] To encapsulate the lyophilized extract, the protein is first heated to 90°C in distilled water and stirred for 10 minutes in a covered flask to prevent water evaporation. Glycerol can then be optionally added and stirred for another 10 minutes at room temperature. The lyophilized pineapple extract is then allowed to cool to 40°C, and the lyophilized pineapple extract is then added, stirring continuously until it is incorporated into the encapsulation equipment.

[0225] To carry out the encapsulation, a commercially available Mini Spray Dryer B-290 (BUCHI Switzerland) spray-drying system was used under the following operating conditions: Operating temperature: 130 ± 5°C, 100% spraying, flow rate of 30 mL / min, and 100 mL of total solution analyzed. The obtained capsules were stored at -20°C until use.

[0226] Based on the results obtained and shown in Table 9, it is possible to observe that treatment P2 (6% w / v protein) showed better encapsulation efficiency (EE) and encapsulation yield (RE). Table 9. Encapsulation efficiency and yield.

[0227] Concentration Concentration

[0228] Treatment

[0229] Extract (%) WPI (%) EE (%) RE (%)

[0230] P1 5 3 23 ± 3 44 ± 1

[0231] P2 5 6 69 ± 1 53 ± 3

[0232] P3 5 12 47 ± 4 48 ± 1

[0233] Encapsulation efficiency (EE) is calculated from the ratio of encapsulated active material to the theoretical or available material to be encapsulated.

[0234] EE (%) = (Total amount of extract in the microcapsules / Total initial amount of extract) x 100

[0235] On the other hand, the encapsulation yield (ER) reflects the percentage of capsules obtained with respect to the total amount of material (active extract + encapsulating agent) used.

[0236] Using the conditions of P2 treatment (5% extract, 6% WPI), the freeze-dried extract from unfermented pineapple and the freeze-dried extract from fermented pineapple were encapsulated.

[0237] To determine the extraction efficiency, the TPC test was performed to determine the total polyphenols in the initial extract and in the capsules (Table 10).

[0238] To extract polyphenols from the capsules, 200 mg of the microcapsules were weighed, and 1 mL of acetonitrile and 1 mL of a methanol:acetic acid:water solution (50:8:42 v / v / v) were added. This dispersion was stirred at the vortex for 1 min and then ultrasonicated twice for 20 min. Samples were filtered through 0.45 µm filters. Once the process was completed, the liquid was collected and stored in a cool, dark place until analysis.

[0239] Table 10. Encapsulation efficiency (%) for capsules containing fermented and unfermented freeze-dried pineapple extract _ EE (%)

[0240] Unfermented freeze-dried pineapple extract 61 ± 3

[0241] Fermented freeze-dried pineapple extract 50.9 ± 1.2 In addition, the antioxidant capacity of both the encapsulating agent and the capsules with unfermented freeze-dried pineapple extract and the capsules with fermented freeze-dried pineapple extract were determined.

[0242] The results obtained are those shown in table 11:

[0243] Table 11. Antioxidant capacity (mg trolox / 100 g capsules) for capsules containing fermented and unfermented freeze-dried pineapple extract

[0244] FRAP ABTS

[0245] Encapsulating agent (WPI) 87.1 ± 0.8 Capsules with lyophilized extract

[0246] 430 ± 9 485 ± 13 unfermented

[0247] Capsules with lyophilized extract

[0248] 1651 ± 19 1667 ± 41 fermented

[0249] From the results in Table 11, it is concluded that the capsules prepared from fermented freeze-dried extract have an antioxidant capacity up to three times higher than the value measured for the capsules of unfermented freeze-dried extract.

[0250] Figures 5 and 6 show the FTIR spectra of the capsules with unfermented freeze-dried extract and the capsules with fermented freeze-dried extract, respectively.

[0251] Again, in both spectra the wave number (expressed in cm) is represented on the abscissa axis. -1 ) and on the ordinate axis the absorption intensity.

[0252] 2. Preparation of materials with unencapsulated antioxidant extract from pineapple by-products.

[0253] The materials were prepared using the extrusion technique. First, a laboratory-scale MC 15 twin-screw mini extruder (Xplore) coupled with an IM 5.5 microinjector (Xplore) was used to manufacture microinjected specimens. The processed formulations were based on the PCL polymer.

[0254] Specifically, a control was manufactured, consisting only of PCL (Capa 6500D, Ingevity) and test tubes with different weight percentages of fermented and unfermented freeze-dried pineapple extract (10 and 15%).

[0255] The temperature profile used in the extruder was 60 - 65 - 70°C with a screw speed of 100 rpm and a residence time of 4 min with a constant supply of nitrogen to avoid possible degradation.

[0256] Regarding the injection conditions, an injection temperature of 60°C was used. Injection pressures and injection times of 4 - 4 - 4 bar and 1 - 0.05 - 4 s, respectively, were used in the test tubes. Figure 7 shows, as an example, the PCL materials with 10% fermented freeze-dried extract.

[0257] Of the aforementioned materials, the FTIR spectra obtained are shown (figures 8 to 12), such that - figure 8 being the control material, where the abscissa axis corresponds to the wave number (expressed in cm -1 ) and the ordinate axis corresponds to the absorption intensity - it is confirmed that after processing by extrusion, the spectra in figures 9-12 show the presence of the fermented freeze-dried pineapple extract.

[0258] Again, in the FTIR spectra of Figures 8-12 the wavenumber (expressed in cm) is represented on the abscissa axis. -1) and the absorption intensity is represented on the ordinate axis.

[0259] The assignment of the main absorption bands to the corresponding functional groups is shown below:

[0260] 2941.9 cm -1 : Stretching -CH2 asymmetric

[0261] 2864.7 cm -1 : Stretching -CH2 symmetrical

[0262] 1719.2 cm -1 : Stretching tension carbonyl -C=O

[0263] 1239.0 cm -1 : Asymmetrical COC Stretch

[0264] 1160.9 cm -1 : Symmetrical COC Stretch

[0265] Figure 9 corresponds to the FTIR spectrum of the PCL CAPA 6500 material + 10% unfermented freeze-dried extract.

[0266] Figure 10 corresponds to the FTIR spectrum of the PCL CAPA 6500 material + 15% unfermented freeze-dried extract.

[0267] Figure 11 corresponds to the FTIR spectrum of the PCL CAPA 6500 material + 10% fermented freeze-dried extract.

[0268] Figure 12 corresponds to the FTIR spectrum of the PCL CAPA 6500 material + 15% fermented freeze-dried extract. As can be seen in Figures 9-12, in which the abscissa axis corresponds to the wavenumber (expressed in cm -1 ) and the ordinate axis corresponds to the absorption intensity, the main absorption bands observed are the same as those appearing in the spectrum of the control PCL CAPA 6500 (Figure 8), except for the broad band that appears in the area of ​​approximately 3000-3500 cm -1 , related to the vibration and stretching stresses of the OH functional group that confirms the presence of the freeze-dried pineapple antioxidant extract in the material.

[0269] In addition, the results of thermogravimetric analysis (TGA) of the materials including 10% unfermented freeze-dried extract and 15% unfermented freeze-dried extract, respectively, are also shown in Figures 14 and 15. In the TGA analysis in Figures 13-15, temperature (expressed in °C) is represented on the abscissa axis and mass (expressed in %), on the ordinate axis, while the first derivative of the sample weight with respect to time is represented on the secondary ordinate axis.

[0270] Thus, once again, the presence of the antioxidant extract of freeze-dried pineapple is confirmed in the materials analyzed in Figures 14 and 15, where the presence of the band related to the loss of mass around 200°C is observed. This band does not appear in Figure 13, which corresponds to the control sample (whose FTIR spectrum corresponds to Figure 8).

[0271] To determine the antioxidant capacity of the developed materials (processed with both fermented and unfermented pineapple extract, but both unencapsulated), these materials were analyzed using the FRAP method. To do this, the materials were cut into small pieces and immersed in a 70% ethanol solution. The solution was covered and left to macerate for two days in an oven at 40°C.

[0272] Table 12 shows the results obtained from the FRAP method (mg Trolox / 100g material) for PCL materials with 10 and 15% unfermented freeze-dried pineapple extract.

[0273] Table 12. PCL + 10% pineapple extract PCL + 15% unfermented freeze-dried pineapple extract unfermented freeze-dried

[0274] Maceration EtOH 70% 76 ± 6 105 ± 1

[0275] The antioxidant capacity of PCL materials with 10 and 15% fermented freeze-dried pineapple extract (unencapsulated) was also evaluated, both by the FRAP method and the ABTS method, after the same maceration procedure described above.

[0276] The FRAP and ABTS results (expressed in mg Trolox / 100g material) for the PCL materials without additives and with 10% and 15% fermented freeze-dried pineapple extract are shown below in Table 13.

[0277] Table 13

[0278] FRAP ABTS

[0279] PCL control without additives 4.09 ± 0.03 12.2 ± 0.4

[0280] PCL + 10% pineapple extract 119 + 7

[0281] 139 ± 6 fermented freeze-dried

[0282] PCL + 15% pineapple extract 295 ± 6 fermented freeze-dried

[0283] As can be seen from the antioxidant capacity results obtained, the fermentation process is essential to significantly increase the antioxidant capacity of the developed materials.

[0284] 3. Preparation of materials with encapsulated antioxidant extract from pineapple by-products.

[0285] First, flexible PCL films were developed by incorporating, by extrusion, the encapsulated unfermented pineapple extract. Table 14 shows the results regarding the antioxidant capacity of the flexible films containing capsules of unfermented freeze-dried pineapple extract (5, 10 and 15% by weight of capsules): Table 14. mg Trolox / 100g flexible film with unfermented pineapple extract capsules

[0286] Concentration of FRAP ABTS capsules

[0287] 5% 14.8 ± 0.5 5.3 ± 0.6

[0288] 10% 28.7 ± 0.3 32.29 ± 0.18

[0289] 15% 44.8 ± 0.7 80 ± 4

[0290] Clearly, an increase in the antioxidant capacity of the materials is observed as the concentration of capsules in them increases.

[0291] Figures 16, 17, and 18 show the FTIR spectra of a flexible PCL film material containing 5, 10, and 15% unfermented freeze-dried pineapple extract capsules, respectively. The abscissa axis of the FTIR spectra corresponds to the wavenumber (expressed in cm -1 ) and the ordinate axis corresponds to the absorption intensity.

[0292] As can be seen in figures 16, 17 and 18, the main absorption bands observed are the same as those appearing in the spectrum of the control PCL CAPA 6500 (figure 8), except for the broad band that appears in the area of ​​approximately 3000-3500 cm -1, related to the vibration and stretching stresses of the OH functional group present in figures 16-18 which, again, confirms the presence of the pineapple extract in the material.

[0293] Thus, the broadband corresponding to the OH functional group is identified at the following wave numbers:

[0294] To confirm the presence of the protein capsule in the developed materials, the most characteristic peaks of the protein are associated with a double bond and appear near 1550 and 1650 cm -1 , associated with Amide II and Amide I, respectively. There is also another significant peak around 3300 cm -1 associated with the stretching of the NH bond in proteins. In this case, this peak appears around 3400 cm -1 , with very little intensity.

[0295] Figures 19, 20, and 21 show thermograms of the PCL materials containing 5, 10, and 15% unfermented pineapple extract capsules. The material is stable up to 400°C, as is PCL alone. The thermograms show temperature (in °C) on the abscissa axis, mass (in %) on the ordinate axis, and the first derivative (DTG, in % / min) on the secondary ordinate axis.

[0296] That is to say, it is concluded that the incorporation of the capsules into the polymeric matrix does not lead to a worsening of the thermal properties of the material, but rather keeps them the same as the PCL base material without antioxidant capsules, something that is very important for the active packaging application for which the developed material is intended.

[0297] The initial degradation temperature of PCL is 378°C, and its maximum degradation temperature is 410°C. The maximum degradation temperature of the protein used as an encapsulating agent is 315°C, and that of the active extract is 196°C.

[0298] Secondly, flexible PCL films were developed by incorporating, by extrusion, the fermented and encapsulated pineapple extract.

[0299] Table 15 shows the results relating to the antioxidant capacity of the developed materials.

[0300] Table 15. mg Trolox / 100g flexible film with fermented pineapple extract capsules

[0301] Concentration of FRAP ABTS capsules

[0302] 5% 22.5 ± 0.7 30.5 ± 1 .0

[0303] 10% 40.5 ± 1 .2 72.7 ± 1 .5

[0304] 15% 68.5 ± 3.1 113.1 ± 0.9

[0305] Clearly, an increase in the antioxidant capacity of the materials is observed when comparing those containing fermented extract with those incorporating unfermented extract. Similarly, antioxidant capacity increases as the concentration of capsules in the material increases.

[0306] Figures 22, 23, and 24 show the FTIR spectra of the prepared materials. Again, as can be seen in the aforementioned figures, where the abscissa axis corresponds to the wavenumber (expressed in cm -1 ) and the ordinate axis corresponds to the absorption intensity, the main absorption bands observed are the same as those appearing in the spectrum of the control PCL CAPA 6500 (Figure 8), except for the broad band that appears in the area of ​​approximately 3000-3500 cm -1, related to the vibration and stretching stresses of the OH functional group which, again, confirms the presence of the extract in the material.

[0307] Regarding the thermogravimetric analyses (TGA) carried out on the materials, Figures 25 and 26 show the thermograms of the PCL materials with 10 and 15% of capsules with fermented pineapple extract, in which it is observed that the material is stable up to 400°C, as is PCL alone.

[0308] In TGA thermograms, the temperature (expressed in °C) is represented on the abscissa axis and the mass (expressed in %) on the ordinate axis, with the first derivative (DTG) (expressed in % / min) represented on the secondary ordinate axis.

[0309] It is concluded that the incorporation of the capsules into the polymeric matrix does not lead to a worsening of the thermal properties of the material, but rather keeps them the same as the PCL base material without antioxidant capsules, something that is very important for the active packaging application for which the developed material is intended.

Claims

CLAIMS 1. Extract characterized in that it is a fermented freeze-dried pineapple extract that comprises: - between 600 and 1800 mg of succinic acid per 100 g of fermented freeze-dried pineapple extract, - between 0.03 and 0.09 mg of gallic acid per 100g of fermented freeze-dried pineapple extract, - between 0.6 and 1.8 mg of syringic acid per 100g of fermented freeze-dried pineapple extract, - between 0.04 and 0.12 mg of coumaric acid per 100 g of fermented freeze-dried pineapple extract, and - between 0.225 and 0.680 mg of ferulic acid per 100g of fermented freeze-dried pineapple extract, so that the extract comes from pineapple by-products and is an antioxidant extract with a total polyphenol content (TPC) of at least 2245 mg Trolox per 100g of fermented freeze-dried pineapple extract.

2. Packaging material characterized in that it comprises polycaprolactone (PCL) reinforced with the fermented freeze-dried antioxidant extract, according to claim 1. a , which is encapsulated and where the extract is present in at least 10% of its total weight, constituting a material with a total polyphenol content (TPC) of at least 115 mg Trolox / 100g material.

3. Packaging material, according to claim 2 a , characterized by the fact that the pineapple by-product is made up of pineapple trunk.

4. Packaging material, according to claim 2 a , characterized by being a flexible film.

5. Packaging material, according to claim 2 a , characterized by being transparent and having a thickness between 0.080 mm and 0.120 mm.

6. Method for manufacturing the extract, according to claim 1 a , characterized by comprising the following stages: Grinding of the frozen pineapple by-product and dehydration of the ground product at a temperature between 25°C and 40°C for at least 48 hours. - Addition of an aqueous ethanol solution with a concentration of at least 50% to the ground and dehydrated pineapple by-product obtained in the previous stage, Ultrasound-assisted extraction applying an amplitude of at least 65%, and maintaining the temperature below 45°C, Centrifugation of pineapple by-product, Recovery of the supernatant corresponding to the pineapple extract, Elimination of ethanol contained in the supernatant by applying vacuum and a maximum temperature of 40°C, obtaining the pineapple extract, - Addition of fresh yeast to the pineapple extract, Fermentation by stirring the solution obtained in the previous stage in a closed system at a temperature between 32°C and 37°C for at least 3 days, Filtering the solution, removing yeast residues, obtaining a solution of fermented pineapple extract, Freezing of the fermented pineapple extract solution at a temperature less than or equal to -20°C, Lyophilization and obtaining a freeze-dried pineapple extract in powder, Where the ultrasound-assisted extraction has a yield of at least 45% and the freeze-dried pineapple extract powder obtained is antioxidant, is fermented and has a total polyphenol content (TPC) of at least 2245 mg Trolox per 100g of fermented freeze-dried pineapple extract.

7. Method for manufacturing the extract, according to claim 6 a , characterized in that in ultrasound-assisted extraction an extraction time of 5 minutes and at least a number of cycles equal to 2 are applied.

8. Method for manufacturing the extract, according to claim 6 a, characterized in that the centrifugation of the pineapple by-product is carried out for at least 10 min at a speed of at least 4000 rpm.

9. Method for manufacturing the extract, according to claim 6 a , characterized by the fact that during fermentation, agitation of at least 200 rpm is applied.

10. Method for manufacturing the extract, according to claim 6 a , characterized in that in freeze-drying a temperature between -55°C and -35°C and a pressure between 0.200 and 0.5 mbar are applied for approximately 48 hours.

11. Method for manufacturing the packaging material according to claim 2 a , characterized in that after lyophilization and obtaining the lyophilized pineapple extract in powder, according to claim 6 a , the following steps are carried out to obtain the material according to any of claims 2 a to 5 a : Dispersion of a solution of encapsulating agent together with the freeze-dried pineapple extract, and atomization-drying by means of an air current at a temperature greater than 100°C, obtaining solid capsules containing the freeze-dried pineapple extract inside. Extrusion of solid capsules containing the freeze-dried pineapple extract inside with PCL to obtain a packaging material, the freeze-dried pineapple extract being present in at least 10% of the packaging material and where the packaging material has an antioxidant capacity and a total polyphenol content three times greater than a material obtained without the fermentation stage.

12. Manufacturing process of the packaging material, according to claim 11 a , characterized in that glycerol is added to the dispersion of the encapsulating agent solution together with the lyophilized pineapple extract.

13. Manufacturing process of the packaging material, according to claim 11 a , characterized in that the encapsulating agent is a milk protein.

14. Manufacturing process of the packaging material, according to claim 11 a , characterized in that the extrusion is carried out at at least 60°C and with pressures and injection times of 4 - 4 - 4 bar and 1 - 0.05 - 4 s, respectively.

15. Use of the packaging material according to any of claims 2 a to 5 a , in packaging of fatty foods to increase their shelf life.

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