Effect of perforation-mediated modified atmosphere packaging and storage duration on physicochemical properties and microbial quality of fresh minimally processed ‘Acco’ pomegranate arils

Flaxseed gum based biocomposite film modified with betel leaf extract: A novel packaging material for oxidative stability of meat patties

The study investigated the antioxidant effect on lipid and protein oxidation, microbial count and other physicochemical attributes of meat patties packaged in flaxseed gum (FSG) based films added with betel leaf extract (BLE) during refrigerated storage (4 ± 1 °C) of 30 days. FSG films were developed after incorporating 0, 2.5, 5, 7.5 and 10% of BLE (BLE0, BLE1, BLE2, BLE3 and BLE4) respectively. The patties showed no change in pH due to composite films however, a remarkable effect in retarding the weight loss and color change along with an improvement in sensory score and microbial quality. TBARS of the patties packed in treated films ranged from 0.10 to 0.99 (mg MDA/kg), lower than that of the control 0.34-1.33 (mg MDA/kg). The BLE4 (packed in FSG film with 10% BLE) had the lowest metmyoglobin content of 31.71% compared to the control sample (69.02%) on 30th day of refrigerated storage. Further, a significant reduction in moisture and color change was observed in meat patties packed in FSG-BLE composite films compared to the control patties. Hence, this study concluded that the FSG-BLE composite films improves the storage stability by impeding the rate of lipid oxidation indicating the developed film's promising potential as a sustainable material in active packaging for the shelf life extension of high-fat meat products and other perishable food products.

Photocatalytic titanium dioxide reduces postharvest decay of nectarine fruit packaged in different materials through modulating central carbon and energy metabolisms

The capacity of titanium dioxide (TiO2) photocatalysis photocatalytic reactor to prevent and control pathogen infection in nectarine fruit packed in laminated nylon/LDPE, low density polyethylene and microperforated LDPE films was evaluated. Results showed that TiO2 combined with microperforated LDPE packaging (TPL) exhibited superior inhibition of microbial growth, reducing total viable counts by 4.18 log CFU g-1 and yeast and mold counts by 3.20 log CFU g-1, compared to microperforated LDPE packaging alone. TiO2 photocatalysis primed the defense systems in nectarine fruit packed in microperforated LDPE, improving the activity of defense-related enzymes. Metabolomics analysis indicated that l-aspartate, oxaloacetate, and succinic acid involved in central carbon metabolism including the glycolysis and tricarboxylic acid cycle pathways, were significantly upregulated by TPL. TiO2 increased the activity of energy metabolism-related enzymes, adenosine triphosphate, adenosine diphosphate, and energy charge levels to provide adequate energy, thus reducing fruit decay.

Incorporation of betel leaf extract provides oxidative stability and improves phytochemical, textural, sensory and antimicrobial activities of buffalo meat sausages

The antioxidant effect of betel leaf extract (BLE) on lipid and protein oxidation, microbial count and physicochemical attributes was investigated in meat sausages during refrigerated storage at 4 ± 1 °C. Buffalo meat sausages were developed after incorporating 0, 250, 500 and 750 mg kg^-1 of BLE (BLE0, BLE1, BLE2 and BLE3) respectively. The sausages showed no changes in proximate composition due to BLE inclusion, but there was an improvement in microbial quality, color score, textural properties and lipid and protein oxidative stability. Further, higher sensory scores were observed for the BLE-incorporated samples. The images from scanning electron microscopy (SEM) revealed a reduction in surface roughness and unevenness showing microstructure modification in BLE treated sausages compared to the control sausages. Hence, to improve the storage stability and impede the rate of lipid oxidation in sausages, BLE incorporation proved to be an effective strategy.

Antioxidant and Fatty Acid Changes in Pomegranate Peel With Induced Chilling Injury and Browning by Ethylene During Long Storage Times

Pomegranate (Punica granatum) is a non-climacteric fruit with a high antioxidant content in arils and peels, of which 92% are anthocyanins and tannins. However, it is susceptible to chilling injury (CI), a physiological disorder concentrated in the peel, which can affect the organoleptic quality of the fruit. To understand the effects of modified atmosphere and ethylene in responses to stress on the antioxidant quality of the fruit and composition of fatty acids in the peel under CI conditions, the exogenous ethylene treatments (0.5, 1.0, and 1.5 μg L^-1), 1-methylcyclopropene (1-MCP; 1 μl L^-1), modified atmosphere packaging (MAP: XTend™ bags), combined strategy MAP/1-MCP, and package in macroperforated bags (MPB-control treatment) were evaluated. The assay was performed in cold conditions (2 ± 1°C; 85% RH) to stimulate damage and was sampled for 120 days (+3 days at 20°C). During cold storage, CI symptoms began at 20 days in MPB and at 60 days for all treatments with exogenous ethylene; CI symptoms were delayed up to 120 days in MAP, 1-MCP, and the combined MAP/1-MCP treatment. Damage was concentrated in the peel. Ethylene and MPB-control treatments induced significant electrolyte leakage, lipid peroxidation, and oxidative damage. In contrast, MAP alone or in combination with 1-MCP successfully delayed CI symptoms. However, no significant differences were observed between treatments in fatty acid content, e.g., in the peel, oleic acid, linoleic acid, palmitic acid, but a significant loss was noted after 60 days of storage. Cold storage caused an increase in anthocyanin concentration in the peel and arils, increasing up to 12 times in the peel of the fruit treated with ethylene at the final stage of storage (120 days + 3 days at 20°C), with non-significant differences in the tannin content in the peel. During long-term cold storage of pomegranate, MAP and 1-MCP treatments delay and reduce the appearance of CI symptoms. This long cold storage induces an important decrease in the unsaturated/saturated fatty acid ratio, which is not reversed by any postharvest treatment. A higher unsaturated/saturated fatty acid ratio after 1-MCP treatments showed a protective effect in peel tissues. In addition, it was possible to increase the concentration of anthocyanins in the peel of cold-storage pomegranates treated with ethylene.

Effect of Gum Arabic and Starch-Based Coating and Different Polyliners on Postharvest Quality Attributes of Whole Pomegranate Fruit

This study investigated the effect of gum Arabic and starch-based coating and two polyliners (Liner 1-micro-perforated Xtend® and Liner 2-macro-perforated high-density polyethylene) on whole ‘Wonderful’ pomegranate fruit during cold storage (5 ± 1 °C and 95 ± 2% RH). Uncoated (UC) and coated (GAMS) fruit were packaged into standard open top ventilated cartons (dimensions: 0.40 m long, 0.30 m wide and 0.12 m high) with (GAMS + Liner 1, GAMS + Liner 2, UC + Liner 1 and UC + Liner 2) or without (UC and GAMS) polyliners. After 42 d, treatment GAMS + Liner 1 recorded the least weight loss (4.82%), whilst GAMS recorded lower (8.77%) weight loss than UC + Liner 2 (10.07%). The highest (24.74 mLCO2 kg−1h−1) and lowest (13.14 mLCO2 kg−1h−1) respiration rates were detected in UC and GAMS + Liner 1, respectively. The highest and lowest total soluble solids were recorded for GAMS (16.87 °Brix), and GAMS + Liner 1 (15.60 °Brix) and UC + Liner 1 (15.60 °Brix), respectively. Overall, no decay was detected for coated fruit packaged with either Liner 1 or Liner 2. Therefore, the combination of GAMS with Xtend® polyliners proved to be an effective treatment to maintain the quality of ‘Wonderful’ pomegranates during storage.

Effects of cinnamon essential oil and Persian gum on preservation of pomegranate arils

Given the high perishability of pomegranate arils, edible antimicrobial coating will enhance their shelf life and maintain their marketability. An antimicrobial coating was prepared using 1% (w/v) soluble part of Persian gum (PG) and different concentrations (0.25%, 0.50%, and 0.75% (v/v)) of cinnamon essential oil (CEO) to extend the shelf life of pomegranate arils. Microbiological, chemical, physical, and sensorial characteristics of coated and uncoated samples were evaluated at 7-day intervals. Total anthocyanin (TAN), titrable acidity (TA), and ascorbic acid showed a decreasing trend, during the whole period of the storage. TAN, TA, and ascorbic acid decreased from 119.8 to 44.5 mg/L, 1.6% to 1.37%, and 682 to 140 mg/L, respectively. Firmness increased during the storage time, while total soluble solids (TSS, around 17.4 °Brix) and total phenolic compounds (TP, around 14.21 mg/100 ml) showed no significant changes with CEO concentrations. Coatings containing 0.5% and 0.75% CEO significantly prevented fungal growth on the samples at least for 3 weeks and 3 months, respectively. Optimization proved that 1-week cold storage and 0.43% CEO could dramatically meet 80% of the research targets including maximum nutritional quality and freshness, as well preventing microbial spoilage. It was concluded that coating the pomegranate arils by PG and selecting an appropriate concentration of the CEO could considerably increase shelf life, marketability, and nutritional quality of pomegranate arils at a suitable and acceptable level.

Effect of Different Modified Atmosphere Packaging on the Quality of Mulberry Fruit (Morus alba L. cv Kokuso 21)

The control of temperature and gas composition is essential to maintain the fresh flavor and quality of perishable fruits like mulberry. This study presented a modified atmosphere experiment (MAP) for fresh fruit showing the potential benefits of innovative gas mixing with argon. The effects of MAP were studied on the physicochemical and qualitative attributes of mulberry preserved at 4 ± 1°C and 90 ± 5% R.H. Fresh mulberries were packaged with different gas combinations: MAP1 (4%O₂+6%CO₂+90%N₂), MAP2 (10%O₂+5%CO₂+85%Ar), CTR1 (20.9%O₂+0.04%CO₂), and CTR2 (10%O₂+5%CO₂+85%N₂). Changes in quality parameters were evaluated after 0, 4, 8, and 12 days of storage. Mulberries packaged with MAP had a lower weight loss than CTR samples which lost more than 80% of their initial weight. Furthermore, the results showed that the argon treatment was the best in keeping the fruit juice content, preserving its structure. Despite not showing great differences with MAP1 treatment, Ar allowed to maintain high TSS up to 8 storage days, slowed CO₂ production. The sensory profile of mulberry fruit was not significantly affected by storage in modified atmospheres, and the production of potential unpleasant odors in MAP2 could not be perceived. The results of this study confirm that this innovative approach, using MAP technology, has a potential use in maintaining mulberry fruit quality for a longer time.

Effects of Argon-Based and Nitrogen-Based Modified Atmosphere Packaging Technology on the Quality of Pomegranate (Punica granatum L. cv. Wonderful) Arils

Ready-to-eat pomegranate arils are considered a “functional food” for their health benefits and have desirable sensory characteristics, which have caused an increasing interest by the consumers for this product. The preparation process of ready-to-eat fruit products can cause severe injuries and worsen their quality and shelf life significantly. Modified atmosphere packaging (MAP) has been used broadly in the last years to maintain the quality of processed fruits and showed optimal results, in spite of the possible problems caused by the depletion of O₂ and corresponding accumulation of CO₂ in the package. This study was conducted to evaluate the effects of different MAP treatments, based on nitrogen or alternatively on a noble gas, argon, in combination with refrigerated storage (0, 4, 8, 12, and 16 days at 4 ± 1 °C and 90 ± 5% RH) on the qualitative parameters of pomegranate arils with the aim to prolong their post-harvest life maintaining the original quality. The argon-based MAP treatment (MAPAr) was the one that provided the best results, assuring a limited loss of weight and juice content. The use of noble gas allowed to maintain a high sugar/acid ratio until 16 days from packaging. Sensory analysis on all MAP treated arils and, on the juice, obtained from them were carried out, and judges showed a preference for MAPAr treated arils and juice until day 12 from packaging.

Application of Gum Arabic and Methyl Cellulose Coatings Enriched with Thyme Oil to Maintain Quality and Extend Shelf Life of "Acco" Pomegranate Arils

The effects of gum arabic (GA; 1.5% w/v) and methyl cellulose (MC; 1% w/v) enriched with thyme oil (TO; 0.25 and 0.5% v/v) on the quality of "Acco" pomegranate arils were studied. Coating treatments, namely, MC, MC + TO0.5%, MC + TO0.25%, GA, GA + TO0.5% and GA + TO0.25% were applied on arils by dipping, and evaluations were made on physicochemical and microbiological quality, phytochemicals and antioxidant capacity of arils stored (5 ± 1 °C, 95 ± 2% RH) for 16 days. Dipping arils in GA or MC, both containing TO (0.5% v/v) significantly (p < 0.0001) reduced weight loss and enhanced antioxidant activity (FRAP) (p = 0.0014). However, dipping arils in GA combined with TO (0.25% v/v) had the highest influence on reducing aril respiration rate compared with other treatments. Overall, results showed that application of coatings (GA + TO0.5% and GA + TO0.25%) reduced total yeast and mould and total plate counts and maintained quality up to 8 days of storage. These findings suggest that either GA + TO0.5% or GA + TO0.25% coatings have the capability to extend storage life of "Acco" pomegranate arils.

Microporous modified atmosphere packaging to extend shelf life of fresh foods: A review

In recent years, microporous modified atmosphere packaging has been widely concerned because of its adjustable air permeability and low processing cost. With the development and increasing demand of fresh food industry, the limited permeability of film in modified atmosphere packaging can't meet the fresh-keeping requirements of fresh foods, especially vegetables and fruits. Microporous film can flexibly adjust the gas permeability according to the physiological metabolic characteristics of fresh foods, which has gradually become a fresh-keeping technology in the domain of vegetables and fruits. This paper reviewed the research progress of microporous modified atmosphere packaging and its extension on shelf life of fresh foods. The latest applied researches were described in a comprehensive manner, particularly fruits and vegetables. Besides, this article also covered theoretical support and analysis, including the perforation mode, air permeability mechanism and mathematical model of microporous film, the characteristics of fresh foods, pore parameters and traits of film materials. This paper payed attention to the application of environmentally friendly degradable film materials (biological film materials, nano materials) in fruits and vegetables preservation. Research has shown that the degradable material can enlarge the fresh-keeping effect of microporous modified atmosphere packaging, which is worthy of further research and development. Finally, the development trends and directions in the future were discussed.

Effect of red thyme oil (Thymus vulgaris L.) vapours on fungal decay, quality parameters and shelf-life of oranges during cold storage

This work has been aimed at studying the effect of red thyme oil (RTO, Thymus vulgaris L.) on the shelf-life and Penicillium decay of oranges during cold storage. RTO vapours significantly reduced (P ≤ 0.05) the percentage of infected wounds, the external growth area and the production of spores in inoculated orange fruit stored for 12 days at 7 °C in a polypropylene film selected for its appropriate permeability. Among the RTO compounds, p-cymene and thymol were the most abundant in packed boxes at the end of cold storage. The RTO vapours did not affect the main quality parameters of the oranges, or the taste and odour of the juice. The results have shown that an active packaging, using RTO vapours, could be employed, by the citrus industry, to extend the shelf-life of oranges for fresh market use and juice processing.

Effects of packaging and duration on quality of minimally processed and unpitted litchi cv. 'Mauritius' under low storage temperature

Pericarp drying is a major postharvest challenge affecting the shelf life of litchi fruit resulting in loss of market value and consumer rejection. Sulphur dioxide (SO₂) is considered an allergen due to its ability to cause irritation in people, particularly those vulnerable to asthma. Thus, the objective of this study was to investigate the effects of packaging and storage duration without SO₂ on the quality attributes of minimally processed litchi fruit cv. ‘Mauritus’. Minimally processed litchi cv. ‘Mauritius’ were packed inside clamshell trays with different perforation sizes: 0 (P-0), 1.1 mm (P-1), and 5.4 mm (P-2) and stored at 1 °C for 15 days, and then held at 12 °C for 2 days for shelf life study (mimicking retail practices). The least mass loss % was observed in fruit packaged under P-0 followed by P-1 and P-2 until the end of storage. Fruit packed in P-2 (5.4 mm perforation) had the highest firmness compared to samples from other packages, but, they also had the highest decay incidences at day 9. The TSS (°Brix) was highest in fruit packed under P-0 followed by P-2 than P-1 at the end of storage. The TSS:TA increased significantly with storage duration with highest value obtained on day 9 in P-0 (121.63) in comparison to P-1 (108.44) and P-2 (103.35). Ascorbic acid and radical scavenging activity declined with prolonged storage irrespective of package type. Overall litchi fruit were better maintained in non-perforated and 1.1 mm perforated clamshell trays up to 9 days, without decay incidences.

Effects of a rotational UV-C irradiation system and packaging on the shelf life of fresh pistachio

BACKGROUND

In this study, fresh pistachio was exposed to UV-C irradiation (2.1 and 4.5 kJ m^-2 ) in a rotating cylindrical system with seven germicidal UV-C lamps and immediately packed in perforated and non-perforated polyethylene terephthalate (PET). The fruit were evaluated for weight loss, total phenolic content, enzyme activities, color indices (L*, a*, b* and browning index), and microbial counts during 35 days of storage at 4 °C.

RESULTS

UV-C treatment caused a significant decrease (P < 0.05) in the weight loss of fresh pistachios compared to the control. The activity of catalase and peroxidase enzymes was significantly higher (P < 0.05) in irradiated samples packed in non-perforated PET in comparison to those of untreated samples. Irradiation did not inhibit the activity of polyphenol oxidase in treated samples, although a slight decrease in polyphenol oxidase activity was observed in irradiated samples compared to control. The fruit treated with 2.1 kJ m^-2 of UV-C and the control packed in non-perforated PET were lighter (L*), redder (a*), and less yellow (b*) compared to 4.5 kJ m^-2 treated samples. Furthermore, a dose of 4.5 kJ m^-2 UV-C significantly decreased sensory attributes of fresh pistachios compared to the other irradiation level and control.

CONCLUSION

UV-C irradiation at a dose of 2.1 kJ m^-2 and packing in non-perforated PET are recommended for fresh pistachio preservation based on the physicochemical, microbial, and sensory parameters. © 2019 Society of Chemical Industry.

Effects of ethrel, 1-MCP and modified atmosphere packaging on the quality of 'Wonderful' pomegranates during cold storage

BACKGROUND

Pomegranate (Punica granatum) is a non-climacteric fruit susceptible to chilling injury (CI) at temperatures below 5 °C. To understand the influences of ethylene and modified atmosphere on CI physiological disorders of pomegranate, exogenous ethrel (0.5, 1 and 1.5 µg L^-1 ) treatments, 1-methylcyclopropene (1-MCP) (1 µL L^-1 ) exposure, packaging in a modified atmosphere (MAP) (XTend™ bags; StePac, São Paulo, Brazil), a MAP/1-MCP combination, and packaging in macro-perforated bags (MPB) were applied. The treated fruits were cold stored (2 ± 1 °C; 85% relative humidity) and sampled during 120 + 3 days at 20 °C.

RESULTS

During cold storage, CI symptoms started at 20 days in MPB and at 60 days for all exogenous ethylene treatments, and were delayed to 120 days in MAP, 1-MCP and MAP/1-MCP treatments. MPB and ethylene treatments induced significant electrolyte leakage, oxidative damage, lipid peroxidation, ethylene and CO₂ production, and 1-aminocyclopropane-1-carboxylic acid oxidase activity, without any change in total soluble solids, titratable acidity or skin and aril colours. Conversely, MAP by itself, or in combination with 1-MCP application, effectively delayed CI symptoms.

CONCLUSION

During long-term cold storage of this non-climacteric fruit, ethrel application induced endogenous ethylene biosynthesis, accelerating the appearance of CI symptoms in contrast to the observations made for MAP and 1-MCP treatments. © 2018 Society of Chemical Industry.

Delaying microbial proliferation in freshly peeled shallots by active packaging incorporating ethanol vapour-controlled release sachets and low storage temperature

This research was conducted to investigate effects of ethanol vapour released in active packaging and storage temperatures on the quality of freshly peeled shallots. The package tested was a solid polypropylene tray incorporating an ethanol vapour-controlled release sachet. The sachet was made of an aluminium foil film on one side and either low-density polyethylene or nylon/polyethylene on the other. Individual sachets contained silica gel adsorbent as the carrier pre-loaded with ethanol. One sachet was placed in each tray containing the peeled shallots and the tray was heat sealed with the low-density polyethylene film lid. Packages were stored at either 10 or 25 ℃ for 10 d. Trays containing only peeled shallots were designated as controls. High storage temperature stimulated quality changes in the shallots. Although ethanol vapour accumulated in the active package headspace, the extent to which ethanol concentrations increased within the shallots was not significantly different from that in the control packages. Microbial proliferation in terms of yeast and mould counts could be delayed through a combination of 10 ℃ and ethanol vapour released from the low-density polyethylene sachet. The ethanol vapour accumulated in the packages did not have a significant effect on mass loss, firmness, and colour changes in the peeled shallots, or on the concentrations of oxygen and carbon dioxide in the packages.

Flaxseed gum in combination with lemongrass essential oil as an effective edible coating for ready-to-eat pomegranate arils

Flaxseed gum (FSG) in combination with lemongrass essential oil (LGEO) was investigated for coating of ready-to-eat pomegranate arils. FSG was used at 0.3% and 0.6% concentrations and with both concentrations LGEO was incorporated at levels of 0ppm, 200ppm, 500ppm and 800ppm. Changes in headspace gases, physicochemical, microbiological and sensory attributes of pomegranate arils stored at 5°C were studied on different days of analysis during the 12day storage period. Coatings containing LGEO were effective in reducing total plate count and yeast and mold populations. Increasing LGEO concentrations in the coatings resulted in more decline in microbial populations. Reduced weight loss occurred in coated samples as compared to uncoated (control) sample. Coated samples showed a gradual decrease in ripening index in contrast with control where a significantly higher decline was observed. Total soluble solids, pH and titratable acidity significantly varied over the storage period. Color change (ΔE) for control increased steeply over the storage time in comparison to coated samples. Furthermore, chroma decreased while as hue angle increased over time.