Equilibrium Modified Atmosphere Packaging Research Articles

Application of poly(L-lactic acid)-based films for equilibrium modified atmosphere packaging of “Kyoho” grapes and its favorable protection for anthocyanins

Grapes were packaged by different Poly (L-lactic acid)-based packaging films (PLTL-PLEL) and stored at 5 °C for 35 days to investigate the effects of equilibrium modified atmosphere packaging on the quality of “Kyoho” grapes during storage. Changes in physiochemical quality, antioxidant content and senescence of grapes were studied. Furthermore, UPLC-Q-TOF-MS/MS was used to observe and identify key factors influencing the variation of grape anthocyanins under different atmosphere conditions. Alterations in gas components and enzyme activities significantly impacted anthocyanin levels, highlighting oxygen concentration as the primary influence on total anthocyanin levels. The PLTL-PLEL50 packaging resulted in an approximate 5.7% lower weight loss and increased soluble solids by approximately 14.4%, vitamin C, total phenols and flavonoids reaching 60.2 mg/100 g, 8.4 mg/100 g and 7.2 mg/100 g, respectively. This packaging also preserved higher anthocyanin levels, with malvidin-3-glucoside and peonidin-3-glucoside at 0.55 μg/mL and 1.62 μg/mL, respectively, on the 35th day of storage.

Combined effect of electrolyzed water (EW) and sonication with equilibrium modified atmosphere packaging for prolonging storage stability of fresh strawberry.

This research focuses on the effectiveness of electrolyzed water (50 and 100 ppm for 3 min), ultrasonication (80 W for 3 min), and their combinations on fresh strawberries, which are then packaged using microperforated film to enhance their storage stability. The gas composition in the headspace, pH, soluble solids, color (L*, a*, b*, and ΔE* values), anthocyanins, total phenolics, and texture profile was evaluated for the 35 days of storage at +4 °C. The lowest weight loss was measured at about 100 ppm electrolyzed water (EW; 0.47%), and the highest one was in the control group (0.57%) after storage. At the end of the storage, O2 in the headspace decreased from 20.90% to 10.50-8.10% and CO2 was accumulated from 0.03% to 16.4-14.34%. The results showed that soluble solids decreased (9.95 to 8.48-7.85 °Bx) and pH values increased (3.34 to 3.79-3.91) during storage. At the end of the storage, the total phenolics in the control group decreased by the most during storage (from 1209.09 ppm to 808.00 ppm), whereas the 50 ppm EW group had the highest (931.66 ppm). Further, the significantly highest anthocyanin amount was found to be 143.86 ppm in the 100 ppm EW group at the end of 28 days of storage. The EW can significantly delay the degradation of anthocyanin over the storage period. The sonication at 100 ppm EW damages strawberry tissues, reducing their hardness. The lowest decay rate was found in fruits treated with 100 ppm EW (41.67%), followed by 50 ppm EW (58.33%), compared to the control (75.00%). This study reveals that applications of the 50 ppm EW and also 50 pm EW combined with ultrasonication have great potential in the extending storage stability of the fresh strawberries.

Design of equilibrium modified atmosphere packaging for postharvest cabbages preservation based on introducing available active sites into film materials as gas transport channels

This work aims to explore an available avenue to design an equilibrium modified atmosphere packaging (EMAP) by the modification of gas permeability of material. In this work, the introduction of available active sites endowed materials with adjustable gas permeability properties. With varying concentrations of the resulting materials with various gas permeability, the CO2 and O2 gas permeability of the blending films were modified at the range of 3.92 ∼ 17.84 barrier and 0.65 ∼ 3.46 barrier, respectively. On this basis, the films were used as EMAP to preserve postharvest cabbages. The results indicated that each EMAP achieved an equilibrium atmosphere containing 6.8 % ∼ 3.8 % CO2 and 2.1 % ∼ 5.2 % O2 within 15 h and maintained it continuously. In these atmosphere, the respiratory rate of the preserved cabbages was significantly inhibited, thereby delaying the deterioration of their storage quality. As the results, sensory scores of the preserved samples were maximally maintained. Declines of color indexes and texture indexes were obviously inhibited. Chemical variations in chlorophyll content, total phenolics content, total flavonoids content, ascorbic acid and nitrite content were significantly suppressed. The overall findings revealed that this method is suitable and promising to develop EMAP for the postharvest vegetables.

Impact of silicon-enriched plant biostimulant treatment on shelf-life of baby spinach (Spinacia oleracea) crops

This research presents the findings from a series of experiments to assess and quantify the influence of compostable plastic packaging in combination with silicon biostimulant on waste produced in a typical leafy horticultural product. The research was conducted firstly by using an agricultural biostimulant consisting in varying supplementation with monosilicic acid, performed in 16 blocks with 3 different treatments and compared against the control samples. In addition, Equilibrium Modified Atmosphere Packaging (EMAP) packaging was designed using polypropylene (OPP) and compostable polylactic acid (PLA) films in order to assess the effect of potential mitigation of food waste production in combination with sustainable films. Storage studies were conducted to assess the amount of product that would run out of specification across a usability period of 7 days as an estimation of waste. The results show that 1 % waste was produced with OPP and no-mitigation, experiments showed a potential waste of 26 % using compostable films. The silicon-based supplementation managed to reduce waste by an average of 35 % in the case of the use with PLA. The results of this study establish a potential pathway for transition towards sustainable films in short shelf-life horticultural products using bio-stimulants with controlled dependents on EMAP.

Regulation of respiratory rate and storage quality of postharvest cauliflower based on gas permeability modification using gas barrier (GB) - gas conductor (GC) blending packaging

The aim of this work is to explore a method to develop equilibrium modified atmosphere packaging (EMAP) via density of available active site (AAS). Sulfonated poly etheretherketone (SPEEK) was prepared as a component to promote gas permeation, i.e. gas conductor (GC). It was mixed with polysulfone (PSF) as gas barrier (GB). With varying GC and GB concentrations, the prepared EMAP provided internal equilibrium atmospheres with 1.8% - 7.2% CO2 and 3.1% - 4.4% O2, in which respiratory rate of preserved cauliflower was inhibited and thereby the storage quality was maintained. Final sensory score of the cauliflower samples preserved in EMAP for 30 days was better than that of control samples (3.5 vs. 1.6), while the texture properties were maintained compared to those in the control samples. Additionally, the inhibitory effects were also shown in color parameters and chemical indicators. The findings in this work would promote the development of modified atmosphere packaging technology.

Preparation and application of equilibrium modified atmosphere packaging membranes with polylactic acid and polymers of intrinsic microporosity

PIM-1/PLA equilibrium modified atmosphere packaging (EMAP) membranes were prepared by polylactic acid (PLA) and polymers of intrinsic microporosity (PIM-1). PIM-1/PLA membranes blocked light transmission due to the strong light absorption of PIM-1, thus reducing the damage of light irradiation to mango. Meanwhile, the moisture permeability and gas permeability of PIM-1/PLA membranes increased with the addition of PIM-1, and the highest values appeared at 1.00 % PIM-1/PLA membrane. This feature was contributing to achieving gas equilibrium concentration (10.5–13.5 % of CO2 and 8.1–9.1 % of O2) and discharging water in the membrane, thus providing optimal environment for mango storage. Moreover, the mechanical properties of PIM-1/PLA membrane with more than 0.25 % PIM-1 addition were slightly lower than those of pure PLA membrane, while the elongation at break was not affected. During the mango preservation, 1.00 % PIM-1/PLA membrane inhibited the respiration rate and delayed the quality deterioration, showing the significant potential application as EMAP membrane.

Leaf porous structure Inspired packaging film for fruits preservation and monitoring CO2 concentration of package

The preservation of fresh fruit and vegetables is always a challenge. Equilibrium modified atmosphere packaging (EMAP) is ideal for preserving fresh produce. The gas transmission and selectivity of EMAP films is crucial for achieving atmospheric equilibrium in packaging. Inspired by leaf porous structure regulating their gas exchange function, we selected natural porous diatomite as the gas channel and modified it with polyethyleneimine (PEI). By introducing diatomite into the film matrix of CNFs, the gas transmission and CO2/O2 selectivity of EMAP films were regulated. The atmosphere in all the packages of EMAP films reached equilibrium within 24 h, which kept the fruit in low intensity aerobic respiration. The EMAP film of DgP7.5 (O2 transmission rate 43.33 cc m−2 day−1 bar−1, CO2/O2 selectivity 1.56) was found to be the most suitable for packaging litchis and green plums. Diatomite with porous structures will provide a design concept for EMAP films.

Combined effect of sonication and equilibrium‐modified atmosphere packaging to improve storage stability of “Angelino” plums during extended storage

AbstractThis work focuses on the combined effects of ultrasound treatment (100, 200, and 300 W for 5 min) and equilibrium‐modified atmosphere packaging (EMAP) to enhance the storage stability based on pH, aw, gas compositions in headspace, color changes (L*, a*, b*), organic acids, and texture profile of fresh “Angelino” plums for 120 days at 4°C. The results were expressed that pH values were increased (3.19‐initial to 3.69/300 W–3.86/control) and Brix values were decreased (16.9‐initial to 14.70/control–15.3/100 W) during storage. At the end of the storage, except the control group, O2 in the headspace decreased from 20.9%‐initial to 16%/300 W–18.5%/200 W and CO2 was accumulated from 0.03%‐initial to 4.9/%200 W–6.5%/300 W. Hardness (from 11,677, 6124 gf), gumminess (from 4344 g to 4335–6715 g), and chewiness (from 3831 and 2326–2638 g) consistently decreased as a function of storage. The hardness of “Angelino” plums had been maintained after the sonication combined with EMAP compared with the control during storage. The 100 W and 200 W sonication could significantly delay the degradation of malic (from 8957 to 4227–4236 mg/L) and tartaric (1796 to 1703–1722 mg/L) acid in flesh plums, but not citric acid and malonic acid over the storage period. The sonication (200 W) combined with EMAP enhanced the storage stability.Practical ApplicationsThis research demonstrates that packaging fresh Angelino plums with micro‐perforated lid films and subjecting them to sonication can enhance their storage stability, allowing for longer distribution via sea freight at a considerably reduced cost compared with air freight. This can potentially expand the producer's reach in international markets. Sonication had great potentials in stabilizing cell wall and maintaining hardness in the plums during storage. Moreover, the application of sonication, especially 200‐W for enhancing storage stability without any detrimental effects on physicochemical properties and natural main organic acids (malic acid) of “Angelino” plums during the storage.

Impacts of smart and active packaging on the quality and storage period of ‘Barhi’ dates

The climacteric nature of ‘Barhi’ dates makes their shelf life very short after harvest. This research aimed to explore the impact of using different packaging materials along with reducing the negative effects of ethylene gas on the quality of ‘Barhi’ date fruit by determining the changes in physical and chemical characteristics of stored fruit. For this purpose, ‘Barhi’ date fruits were picked during the Khalal stage and stored using three different packaging materials [carton boxes (control), low-density polyethylene (LDPE), and equilibrium modified atmosphere packaging (EMAP)] with or without ethylene absorbent sachet (EAS) at 0 °C for 40 days. The results indicated that the EMAP bags with EAS under 0 °C gave the highest quality properties of all studied parameters compared to the control treatment. The control treatment recorded the lowest date fruit quality, which lasted only for 20 days of cold storage before converting to the Rutab stage. Using LDPE with EAS instead of the more expensive EMAP bags could be a cheaper way to keep the quality of ‘Barhi’ date fruit and make it last longer during cold storage.phoenix dactylifera

Equilibrium modified atmosphere packaging on postharvest quality and antioxidant activity of strawberry

SummaryMicroporous film and MAP were evaluated to find the optimal method for extending the postharvest storage of strawberry. To determine the most suitable MAP system for strawberry, fruits were stored in controlled atmospheres (O2/CO2 partial pressures in kPa: 5/10; 10/10; 5/15), and in a separate experiment, strawberries were sealed in the container with different microporous PET/PE films. Results showed that the optimum atmosphere of strawberries was 10 kPa O2 + 10 kPa CO2 which could be achieved and maintained by using the microporous film with four perforations of 100 μm. By maintaining the optimal atmosphere, active EMAP could increase polyphenol compounds accumulation, with total phenolic content increased by 25% and the content of anthocyanin and total flavonoid was 13% and 29% higher than control at the end of storage. Meanwhile, active EMAP significantly increased CAT PAL and APX activities and the shelf‐life was prolonged for 6 and 3 days, respectively, compared with strawberries packed in control and passive EMAP.

Construction of gas permeable channel in poly(l-lactic acid) membrane and its control of the micro atmosphere in okra packaging

An atmosphere within a package affects the metabolic process of food and the microbial growth of fresh products and has a vital role in preserving food. It depends on the membrane's specific gas permeability and selectivity to generate a desirable atmosphere for storage. In this study, triblock poly(l-lactic acid‑d-ɛ-caprolactone) (PLDC) copolymers and three-arm poly(l-lactic acid-g-ɛ-caprolactone) (PLGC) star copolymers were synthesized, in which a microphase-separated morphology of sea-island structure was established in PLGC membrane as a gas “fast permeation channel” for regulating CO2 and O2 permeability and CO2/O2 selectivity. AFM observation revealed different well-defined micro phase-separated structures of PLGC with size ranges of 200– 300 nm. Comparing PLGC membrane with PLLA, CO2 and O2 transmission rates increased by 416.9 % and 132.7 %, while H2O transport rates increased by 245.6 %. Mechanical testing shows that the PLGC membrane exhibits 40.8-fold elongation at break compared to PLLA, showing excellent flexibility. Moreover, okra's equilibrium-modified atmosphere packaging was designed based on a theoretically derived model. Preservation results suggested that the PLGC packaging membrane could generate an ideal high 8.7– 9.2 % CO2 and low 2.3– 2.7 % O2 atmosphere for okra preservation, delaying the discoloring and rotting of okra.

A novel insight into green food preservation: Design of equilibrium modified atmosphere packaging (EMAP) based on gas barrier (GB) - gas conductor (GC) blending materials

In this work, the design of equilibrium modified atmosphere packaging (EMAP) was achieved by adjusting gas permeability using gas barrier (GB) - gas conductor (GC) blending material. Sulfonated poly ether ether ketone (SPEEK) was used as promoter for gas permeation, i.e. GC, and introduced into poly ether sulfone (PES) as GB. As the results, the introduction of SPEEK cannot only enhance the gas permeability of the blending material, but also modify the physic and chemical properties. When the blending material used as EMAP for peppers, significant effects were exhibited on inhibiting the variations in sensory, color, texture, and chemical properties of the preserved peppers, especially when the samples preserved in packaging consisted of 60 % SPEEK and 40 % PES, in which suitable atmosphere with 5.18 % v/v CO2 and 3.16 % v/v O2 was maintained. The overall findings revealed the feasibility of GB - GC theory for EMAP design.

Effects of the equilibrium atmosphere on Taleggio cheese storage in micro perforated packaging

Taleggio is an Italian smear-ripened cheese, whose complex microbiota demands the optimisation of the packaging system to avoid excessive changes during storage. Metabolic processes of the cheese rind microbiota can be usefully exploited in equilibrium modified atmosphere packaging (EMAP) by balancing microbiota respiration and film permeation. Here, we present the application of three different micro perforated EMAPs as models for smear-ripened cheese compared to two control packaging configurations. Analyses of the main microbial groups, headspace gas, textural profile, and sensory properties were performed to find the best packaging for storage. Results showed that two of the alternative micro perforated packaging systems were able to control the excessive changes during storage, thus limiting fungal overgrowth and allowing the typical development of smear microbiota with minor changes to hardness and cohesiveness. Finally, the sensory evaluation positively favoured one of the alternatively packed cheeses based on its compactness, typical dairy traits, and minor off-flavours. These findings showed that EMAP can be a valid alternative solution to control the storage of Taleggio cheese. Further studies could be conducted to evaluate this system on other smear cheeses.

Development of a generalised equilibrium modified atmosphere model and its application to the Taleggio cheese

The food metabolic processes influence the gas composition of packaged products: by finely tuning the gas fluxes through the packaging, the aerobic and anaerobic respiration processes can be efficiently exploited to regulate the equilibrium gas concentrations. In this work, we present a generalised model able to predict the evolution of gases in micro-perforated equilibrium MAP, with a detailed evaluation of fluxes through the perforations by means of Computational Fluid Dynamics. It was found that the Sherwood number for the studied micro-perforations is 0.715 and it was confirmed via experiments on packaging with oxygen-depleted atmospheres. The kinetic model was experimentally validated on a smear short-ripened soft cheese (Taleggio) whose complex surface microbiota confer to the product a non-trivial respiration behaviour. Cheese slices were packed with three different micro-perforated solutions (one 120 μm diameter hole, two 90 μm diameter holes, and five 90 μm diameter holes) achieving three different equilibrium gas compositions with good model predictions. The model was applied to literature data with success, thus the model can be deemed general and applicable to many different systems. • A generalised model for equilibrium modified atmosphere packaging (EMAP) with micro-perforation is developed. • Computational fluid dynamics (CFD) is used to predict diffusive fluxes through micro-perforations. • Taleggio cheese EMAP experiments are presented. • The model correctly describes the gas behavior inside the packaging for taleggio cheese and other soft cheese.

Configuration of biodegradable equilibrium modified atmosphere packages, including a moisture absorber for fresh cape gooseberry (Physalis peruviana L.) fruits

Different equilibrium modified atmosphere packaging systems (EMAP) were evaluated for cape gooseberry fruits, including a moisture adsorber. Three packages were used: cellulose trays with a cellulose film, polylactic acid (PLA) trays and film, and polyethylene terephthalate trays (PET) with a film of polypropylene (PP). The packages’ configuration, perforations, and amount of moisture adsorber were predefined by modeling the gas transfer in the packaging system. The packaged fruits were stored at 6 °C and 75 % RH for 6 weeks. The fruits in the PLA trays without sachets had the maximum shelf life of 42 days, while the fruits in celulose with sachets had a shelf life of 40 days compared to 35 days with the PET/PP trays and 21 days of the control fruits. With similar equilibrium gas levels between the EMAP packages, the higher permeability to water vapor of PLA prevented the formation of condensation with lower dehydration compared to the celulose packages with sachets.

Changes in cell wall metabolism and flavor qualities of mushrooms (Agaricus bernardii) under EMAP treatments during storage

To clarify the dynamic changes of cell wall metabolism and flavor components in Agaricus bernardii packed with the packaging materials during storage. The polyethylene (PE), poly (butylene adipate-co-terephthalate)/ poly (l-lactic acid) (ECFPLA) and PBAT/PLLA/ hydrophobic silica (ECFPLASiO2) with a different gas/water vapor permeability were used as equilibrium modified atmosphere packaging (EMAP) materials, and an appropriate gas concentration [O2 (0.01−0.03 %), CO2 (4.58–6.62 %)] was created inside the ECFPLASiO2 packaging, which led to Agaricus bernardii with higher level of cell wall components and lower level of cell wall degrading enzymes during the storage period. For the first time application of HS-SPME–GC–MS on an extract from fresh Agaricus bernardii. The results showed that volatile compounds of fresh Agaricus bernardii mainly consists of alcohols, ketones and aldehydes, with 3-octanol, 3-octanone, 1-octene-3-alcohol and phenylcarbinol being most abundant compounds. During the storage time, the varieties and content of volatile compounds were changed in all treatments. Alcohols, aldehydes, hydrocarbons and esters contents increased during the storage while ketones declined. Among all treatment groups, ECFPLASiO2 group showed higher most abundant compounds and organic acid content. The results suggest that ECFPLASiO2 film could be used to reduce the changes in cell walls and flavor components after harvest and extend the shelf life of Agaricus bernardii.

Organic Chilli Pepper (Capsicum annuum cv. Superhot) Quality and Biochemical Responses to Sequential Treatment with Hot Water, Surface Coating, Equilibrium Modified Atmosphere Packaging and Cold Storage

Organic chilli peppers (Capsicum annuum cv. Superhot) at full-red stage were submeged in 50°C water for 4 minutes followed by surface coating with carboxymethyl cellulose (CMC) or chitosan at 0.25-1.0% for 2 minutes. The fruits were then packed in 32-34 µm thick polyethylene bag (Active PAKTM) before cold storage at 10°C for 12 days followed by 5 days holding at 25°C. The decrease of fruit quality was due to weight loss and decay and these could be reduced by edible coating. Coated fruit had higher titratable acidity, vitamin C content, total phenols, and activities of phenylalanine ammonia lyase, superoxide dismutase and catalase as compared to uncoated fruit. Chitosan was more effective than CMC in bringing these effects, and 0.5% was the most effective concentration. The results indicated that fruit coating by 0.5% chitosan and CMC maintained quality of chilli peppers by slowing physicochemical quality changes and improving the antioxidant system.

Benefit of modified atmosphere packaging on the overall environmental impact of packed strawberries

Life cycle assessment (LCA) was used to address the environmental benefit of using Equilibrium Modified Atmosphere Packaging (EMAP) at ambient temperature as an alternative to the use of conventional macro perforated packaging (MPP) and refrigeration in the strawberries’ farm to fork system. In this purpose, the environmental impact of strawberries’ storage conditions at household in macro perforated packaging put in ambient or cold condition were compared with that of EMAP used at ambient temperature. LCA was applied from production till consumer level taking into account food losses at each step as well as packaging production, disposal and usage benefit, if any, i.e. food losses reduction. Our findings confirmed that for highly perishable product, the production step is the main driver of environmental impacts. As such, the technology of preservation that permits to minimize losses leads to the lowest environmental impact in spite of its direct impacts. For short storage at household, well optimized EMAP system is a valuable alternative to MPP for both low and ambient temperatures while for long storage duration (3d), EMAP at ambient temperature could not substitute for MPP at refrigeration temperature. Finally, sensitivity analysis of results to the food losses parameters at both supermarket and household has revealed that conclusions regarding the best packaging strategy are highly sensitive to these parameters. The main conclusions of this study are that (i) EMAP could be, in several conditions, a valuable option compared to standard packaging strategies, (ii) it is needed to inform consumers on packaging functions in order to preserve EMAP benefit until consumption and (iii) better knowledge of food losses among the supply chain is needed to assess environmental impacts more precisely.

Biodegradable blend films of poly(ε-caprolactone)/poly(propylene carbonate) for shelf life extension of whole white button mushrooms.

Blend films with poly(ε-caprolactone)(PCL) and poly(propylene carbonate)(PPC)with thickness of approximately 40μm and 60μm, respectively, were prepared using a uniaxial-stretching extrusion process to modify the property of PCL. PCL/PPC blend films with better comprehensive properties with thickness about 60μm were used for equilibrium-modified atmosphere packaging of button mushrooms at 5 °C. The gas barrier property together with water vapor permeability were evaluated as well as its effects on the shelf life button mushrooms. The results showed that the PCL/PPC20 and PCL/PPC50 blend films have suitable gas barrier property and water vapor permeability, which was helpful to generate an appropriate storage environment and more importantly no condensation occurred in these two packages. The lower weight loss of button mushrooms was observed for PCL/PPC20 and PCL/PPC50 blend films 4.43 and 4.46, respectively. The PCL/PPC blend films was more effective in decreasing the activity of PPO and preserving the color of the button mushrooms. The over market acceptability of button mushrooms packaged in PCL/PPC blend films still maintained good and within the limit of marketability after 17days of storage.

Oxygen Consumption by Phalaenopsis Plantlets and Chrysanthemum Cuttings as a Function of Temperature and Time: Model Structure Validation

Phalaenopsis spp. and Chrysanthemum are ornamentals with an important economic value. Currently, quality loss during storage and transport of plantlets and cuttings is a limiting factor for spreading the workload, broadening the export range, and the use of slower but more environmentally friendly transport. In the agro-food sector, equilibrium modified atmosphere packaging has enhanced the shelf-life of minimally processed produce. The required properties for an equilibrium modified atmosphere packaging system can be estimated from the respiration rate of the packaged commodity under specified atmospheric composition and storage temperature. In this work, a model structure is validated to estimate the respiration rate as a function of oxygen concentration and temperature for Phalaenopsis and Chrysanthemum. The oxygen concentration as a function of time was monitored in a closed system for different storage temperatures. The models show a good fit to the data. The model coefficients were dependent on the plant species and characteristics. The resulting formulae can be used to estimate the oxygen consumption rate of the produce under a range of oxygen concentrations and a temperature range from 15 °C to 32 °C for Phalaenopsis and from 2 °C to 14 °C for Chrysanthemum. The oxygen concentrations for which the formulae are valid depend on the storage temperature and plant species. The models can be used to estimate a dynamic oxygen consumption rate profile during storage and transport.