Effect of modified atmosphere packaging and superchilled storage on the shelf‐life of farmed ready‐to‐cook spotted wolf‐fish (Anarhichas minor)

Modified atmosphere packaging (MAP) combined with superchilling (?1°C) was evaluated as a mild preservation method for farmed spotted wolf‐fish (Anarhichas minor). Portions were packaged in air and in CO2:N2 (60%:40%) atmosphere with a gas:product ratio of approximately 1, at superchilled (?1.0°C ± 0.2°C) or chilled (+4.0°C ± 0.2°C) temperatures. A reduced bacterial growth (p < 0.001), measured as aerobic plate counts (APC) and psychrotrophic bacteria, was observed in modified atmosphere (MA) packaged wolf‐fish at both ?1°C and +4°C, compared to portions in air. MA‐packaged wolf‐fish had improved odour and flavour scores (p < 0.05), but also a higher drip loss than fish stored in air. A shelf‐life of 15 days was obtained at ?1°C for MA‐packaged fish compared to 8–10 days in air, and at 4°C the shelf‐life was 13 days in MA and 6–8 days in air. Copyright © 2006 John Wiley & Sons, Ltd.     

Effect of hinokitiol impregnated sheets on shelf life and quality of “KEK‐1” tomatoes during storage

Hinokitiol (β‐thujaplicin, volatile oil extracted from the wood of Hiba arborvitae [Thujopsis dolabrata var. hondae], cypress family) is a natural preservative, antimicrobial, and chelating agent, used to prevent decay and extend the shelf life of fruits and vegetables. In the present study, we used nonwoven rayon sheets impregnated with hinokitiol to conduct packaging studies. Mature green tomatoes var. “KEK‐1” were packaged under three packaging conditions, ie, modified atmosphere packaging (MAP), MAP + hinokitiol (MH), and perforated film package (as control), and their quality attributes were compared during storage. The packaging materials used were low‐density polyethylene (LDPE) film (40 μm) and fresh sheets of nonwoven rayon impregnated with hinokitiol. O₂ in the MAP packaged tomatoes were retained throughout the storage period (3% to 5% O₂). Results showed that MH had slightly improved quality attributes throughout the storage period when compared with MAP alone. Expression levels of LeACS, LeADH, and LeTBG4 genes were higher in 5 and 9 days of control when compared with MAP and MH. “KEK‐1” tomatoes had longer shelf life under MAP and MH packaging and maintained the quality at 15°C. Hence, the effect of the MAP with bioactive packaging treatments could be effective in the future application for the extension of shelf life and quality of fruits and vegetables.     

Effects of Modified Atmosphere Packaging with Various Carbon Dioxide Composition on Biogenic Amines Formation in Indian Mackerel (Rastrelliger kanagurta) stored at 5 ± 1°C

The profile of major biogenic amines was investigated in Indian mackerel packed in modified atmosphere for up to 12 days at 5 ± 1°C. Beheaded and gutted Indian mackerel was packed under different carbon dioxide compositions to study the effects on biogenic amines formation. The treatments were control air (C), vacuum packaging (VP), 30% CO₂/65% N₂/5% O₂ (M30C), 60% CO₂/35% N₂/5% O₂ (M60C), 80% CO₂/15% N₂/5% O₂ (M80C) and 100% CO₂ (M100C). Each amine responded differently to different CO₂ levels. After 12 days of storage, concentrations of histamine were reduced by 6.4%, 8.5%, 70.3%, 78.8% and 90.2% in fish packed under VP, M30C, M60C, M80C and M100C, respectively as compared with control air. Changes in putrescine and cadaverine showed a similar pattern. Gas mix of M30C and VP stimulated the formation of tyramine reaching 203 and 172 ppm, respectively. Higher composition of CO₂ had a significant inhibitory effect on tyramine concentration (p < 0.05). There were parallel increases of putrescine and spermidine in C, VP and M30C. No significant effect of CO₂ was observed on spermine (p > 0.05). After 9 days of storage, more than 300 ppm of histamine was detected in mackerel packed in VP and M30C; therefore, these atmospheres pose a histamine intoxication risk. Copyright © 2013 John Wiley & Sons, Ltd.     

Effect of Pretreatment and Modified Atmosphere Packaging on Quality of dry Coleslaw mix

The aim of the study was to determine the effect of soaking in chlorinated water (100 ppm chlorine) or mild thermal treatment in water (55°C; 3 min) and modified atmosphere packaging on the quality and shelf life of dry coleslaw stored for 12 days at 4°C. Samples were packaged in low‐barrier film in modified atmosphere containing: 5/10/85, 20/25/55, 50/30/20, 70/30/0 %O₂/% CO₂/% N₂, and air atmosphere. In‐pack gas levels, sensory quality, microbial counts and cell permeability were determined. In comparison to non‐processed coleslaw, pretreatment of coleslaw, both consisting in soaking in chlorine solution and a mild thermal processing, resulted in a reduction by approx. 1 logarithmic cycle for counts of psychrophilic and lactic acid bacteria as well as mesophilic and psychrophilic yeasts, by 1 and 1.7 logarithmic cycle for coliform bacteria and by 2 up to 3 logarithmic cycles for Pseudomonas bacteria. Modified atmosphere (irrespective of its composition) used in product packaging was found to have no effect on the count of mesophilic bacteria. An elevated content of carbon dioxide in modified atmosphere (10, 25 or 30%) inhibited growth of psychrophilic bacteria and Pseudomonas bacteria up to 6 days of storage. In the case of coliform bacteria growth inhibition during storage was recorded both in the samples packaged in air atmosphere and in the atmosphere of 50/30/20 and 70/30/0 %O₂/% CO₂/% N₂. In samples packaged in the atmosphere of 70% O₂ and 30% CO₂ after 12 days the greatest cell permeability was recorded, which was connected with a deterioration of their microbiological quality. Copyright © 2015 John Wiley & Sons, Ltd.     

Effects of active modified atmosphere on lipid and protein oxidation,moisture migration and quality properties of beef steaks

Fresh beef is a typically perishable food because of its high water and protein content; thus, it requires proper packaging condition and storage temperature to ensure its quality. In this study, the beef steaks were stored at 4°C under HiO₂ modified atmosphere packaging (MAP) (78.8% O₂ + 18.8% CO₂ + 2.4% N₂) and HiCO₂ MAP (60.0% CO₂ + 40.0% N₂). The traditional air packaging (AP) and vacuum packaging (VP) were used as the controls. The total viable count (TVC), colour, water holding capacity (WHC), myofibrillar protein (MP) oxidation and lipid oxidation of beef meat were investigated. The moisture distribution and migration were also analysed using the low-field nuclear magnetic resonance (LF-NMR). The association amongst all parameters was analysed by correlation analysis and principal component analysis (PCA). The results showed that the TVC values in the HiCO₂ MAP (5.6 log CFU/g) steaks were lower than those of VP (5.9 log CFU/g), AP (7.0 log CFU/g) and HiO₂ MAP (6.3 log CFU/g) steaks because of the sufficient CO₂ after 15 days of chilled storage. The bright red colour and the higher WHC were maintained in the HiO₂ MAP steaks than in the AP group during storage. However, higher levels of protein and lipid oxidation also occurred. The beef steaks stored under HiCO₂ MAP had the lowest protein and lipid oxidation and highest value of immobile water content and WHC, however, similar to the VP group, the bright red colour was not shown. The moisture attributes (drip loss, cooking loss and P₂₃), protein oxidation (protein solubility and carbonyl content) and lipid oxidation (TBARS value) have shown a close correlation by correlation analysis and PCA. Overall, two different packaging methods of MAP can prolong microbial-shelf life and maintain higher WHC of beef steaks compared to AP and VP steaks, but higher oxidation level in HiO₂ MAP and unattractive colour in HiCO₂ MAP are concerns that need to be addressed.     

Effect of different modified atmosphere packaging on microbial quality,oxidation and colour of a seasoned ground beef product (meatball)

The effects of different modified atmosphere packaging (MAP) on microbial quality, oxidation and colour of meatballs were investigated. Meatballs were prepared in our laboratory and packaged in vacuum or in different gases: combinations of O₂ (0, 2, 21%) and CO₂ (0, 33, 66, 100%) with N₂ as balance gas. Total microbial count, thiobarbituric acid reactive substances and colour were determined during storage at 3°C for 3 weeks. Total microbial count remained unchanged at around 6.3 LogCFU/g in vacuum and 100% CO₂ packages after 7 days, and slightly increased afterwards. The microbial count was higher in other packages and increased to 7.6 LogCFU/g after 21 days storage. Oxidation was inhibited by reduced O₂ and increased CO₂ in the packages. Packages with low O₂ maintained colour (a‐values) to a greater extent than the packages with higher O₂ levels. MAP containing 1–3%O₂ with 33%CO₂ inhibited microbial growth, oxidation and colour change in meatballs. Copyright © 2009 John Wiley & Sons, Ltd.     

Effect of Different Packaging Methods on Quality and Shelf Life of Fresh Reindeer Meat

The impact of different packaging methods [vacuum, modified atmosphere packaging (MAP) (60% CO₂ and 40% N₂) and MAP + CO₂ emitter] on the quality of fresh reindeer meat (M. semimembranosus) stored at 4°C for 21 days was investigated. Colour and odour of the meat, drip loss, pH, microbial content, antioxidant capacity and cooking loss were measured. The MAP + CO₂ emitter resulted in prolonged microbial shelf life compared with vacuum and MAP without CO₂ emitter as lower level of total viable counts was detected after 13 and 17 days. Samples stored with CO₂ emitter also had lower drip loss. Samples stored in vacuum had significant lower L*‐value, higher a*‐value and lower intensity of freshness (odour and colour) compared with those stored in MAP and MAP with CO₂ emitter. However, MAP with a gas‐to‐product volume ratio of 1 : 1 seems to be too low in quality preserving. Increased partial pressure by adding a CO₂ emitter improved bacterial inhibition compared with vacuum and traditional MAP. Copyright © 2014 John Wiley & Sons, Ltd.     

Effectiveness of modified atmosphere packaging in preserving a prepared ready‐to‐eat food

The effectiveness of modified atmosphere packaging (MAP) was evaluated for a combination prepared food (Korean braised green peppers with dry anchovies). From a preliminary storage test of the ready‐to‐eat dish at 10°C, the aerobic bacterial count on the green peppers was selected as a primary quality index. The effect of MAP with different CO₂ concentrations on the product quality at 10°C was also studied. MAP with a CO₂ concentration of ≥30% extended the lag time and/or reduced the growth rate of bacteria. Finally, the effect of different storage temperatures (5, 10, 15 or 20°C) on the shelf life of the product was investigated. Mathematical modelling of bacterial growth curves under stretch‐wrap air packaging and MAP with 60% CO₂/40% N₂ showed that MAP increased the hypothetical minimum temperature in the square root model that describes the temperature dependence of the lag time and growth rate. MAP conditions of 60% CO₂/40% N₂ extended the shelf life at 10°C by 130% (to 18.4 days) relative to that achieved with stretch‐wrap air packaging (7.9 days) based on the time taken to reach the quality limit of an aerobic bacterial count of 10⁵ CFU/g. The relative extension of shelf life achieved with MAP was greater at lower temperatures. Copyright © 2008 John Wiley & Sons, Ltd.     

Use of Sodium Lactate and Modified Atmosphere Packaging for Extending the Shelf Life of Ready‐to‐Cook Fresh Meal

In this work, the combined effects of sodium lactate and modified atmosphere packaging (MAP) in extending the shelf life of a ready‐to‐cook fresh skewer, made up of raw pork chops and semi‐dried vegetable mix (i.e. zucchini, peppers and tomatoes), were investigated. In the first experimental step, a sodium lactate solution was used to dip pork chops at three different concentrations: 20, 40 and 60% w/w. The second part of the work was focused on the use of MAP. In particular, the following MAPs were tested: MA1 (50%O₂/30%CO₂/20%N₂), MA2 (70%O₂/30%CO₂), MA3 (30%O₂/70%CO₂) and MA4 (30%O₂/30%CO₂/40%N₂). Finally, the optimal concentration of sodium lactate and the best gas composition were combined. The samples were stored at 4 °C; their microbial and sensory qualities were monitored along the entire observation period. The results indicate that the shelf life of the investigated ready‐to‐cook meal can be extended by approximately 83%, if compared with the control skewer packaged in air. The best preservation strategy is the combination of dipping of meat pieces in 40% sodium lactate solution and packaging under MA1. Copyright © 2014 John Wiley & Sons, Ltd.     

The Effect of Active Packaging on Microbial Stability and Quality of Chinese Steamed Bread

The present study was conducted to evaluate the effect of active packaging [oxygen absorber (OA) or oxygen absorber combined with ethanol emitter (OA + EE)] on microbial stability and quality of Chinese steamed bread (CSB) stored at 25 °C. Air‐packaged CSB was taken as control. Microbiological, sensory, physical, thermal and mechanical changes were monitored as a function of treatment and storage time. On day 2 of storage total plate count was reduced by 3.1, 3.7 and 4.4 cfu/g by OA, OA + EE (1% v/v) and OA + EE (3% v/v), respectively (p < 0.05). Yeasts and moulds were inhibited during the entire storage period. No detrimental effects of OA + EE (1% v/v) were observed on organoleptic parameters, whereas OA + EE (3% v/v) gave a strong objectionable flavour and taste. Active packaging significantly (p < 0.05) delayed the increase of potential of hydrogen as compared to the control. No significant effect of active packaging was found on moisture content, water activity, colour and specific volume. An increase in the melting enthalpy of amylopectin crystallite was observed in all samples during storage. The stored CSB samples packaged with OA showed higher values of hardness compared to samples packaged with OA + EE (1% v/v), indicating the potential of ethanol as plasticizer of the protein network. The results indicate the potential application of OA and OA + EE (1% v/v) as an antimicrobial packaging system for CSB preservation. Copyright © 2015 John Wiley & Sons, Ltd.     

Effects of PP‐based Nanopackaging on the Overall Quality and Shelf Life of Ready‐to‐eat Salami

A total of 1% nanoclay containing polypropylene (PP)‐nanocomposite and 1% nanoclay plus 5% poly‐beta‐pinene (PβP) containing PP‐active‐nanocomposite materials were produced and tested for packaging of sliced salami. The sliced salami was packaged using both nanofilms and multilayer film of PP/PA/EVOH/PE under vacuum, modified atmosphere packaging under 50% CO₂ and 50% N₂ and air and stored at 4 °C for 90 days. During storage, headspace gas composition; microbial, physical and chemical analyses; and sensory evaluation were performed. The antimicrobial effect of PβP containing nanomaterial was pronounced under vacuum, and no bacterial growth was observed for 75 days. An a* value decreased notably in all applications during storage and preserved best by the multilayered material under vacuum and high CO₂. Thiobarbituric acid reactive substances (TBARS) were 0.63 mg MDA/kg after the processing and gradually increased at all applications during increased storage. TBARS values of all vacuum applications were lower than that of modified atmosphere packaging applications. Rancid taste development was determined by sensory panelists when TBARS values were higher than 0.80 mg MDA/kg on the 90th day. There was no significant moisture loss, and no increase in hardness was determined during the whole storage time. The longest shelf life was 75 days for the sliced salami under vacuum and high CO₂ using the multilayer material. PβP containing nanomaterial provided 50 days of shelf life under vacuum, which is commercially considerable. Copyright © 2017 John Wiley & Sons, Ltd.     

Modified atmosphere packaging affects lipid oxidation,myofibrillar fragmentation index and eating quality of beef

The objective of this study was to evaluate the effects of different modified atmosphere packaging (MAP) systems applied during ageing and retail display on the quality of beef longissimus dorsi. The quality of the steaks was measured by sensory analysis, thiobarbituric acid‐reactive substances (TBARS), myofibrillar fragmentation index (MFI), protein oxidation, weight loss, cooking loss and vitamin E content. The study included 11 different packaging systems investigated in two separate trials, using O₂, CO₂, N₂ gas and vacuum in combination or alone during ageing and retail display. In some systems, loins were sliced into steaks before packaging, and in other systems, loins were vacuum packed and aged for 14–18 days, and thereafter were sliced and repacked in different atmospheres. Systems including high O₂ MAP resulted in a large increase in warmed‐over flavour and in TBARS as well as a decrease in juiciness, tenderness and vitamin E content, compared to anaerobic systems. Also, MFI was lower in high O₂ MAP steaks, and an increase in protein oxidation was seen, suggesting that the decrease in meat tenderness was due to reduced proteolysis and/or protein oxidation. In addition, the cooked steaks of high O₂ MAP looked well done, although the internal temperature was only 62°C, indicating premature browning. Ageing of steaks in N₂ did not affect any measured parameter compared to vacuum thermoforming packed muscle. Steaks stored in vacuum skin pack for 20 days were less tender than steaks stored in 100% N₂ for 18 days followed by 2 days in atmospheric air. In conclusion, packaging in high O₂ concentrations compromises several aspects of meat quality. Copyright © 2008 John Wiley & Sons, Ltd.     

Preservation of strawberries by modified atmosphere packages with other treatments

The impact of modified atmosphere packaging (MAP), in combination with ozone treatment and an edible film coating, on the preservation of strawberries was studied. A combination of 2.5% O₂ with 15% CO₂ was the optimum gas composition for the MAP of strawberries and prolonged shelf‐life by 4–6 days. When the strawberries were pre‐treated with a 4.3 mg/m³ ozone water dip and an edible coating prior to packaging, the shelf‐life was extended to 8–10 days. The results showed that two treatments [No.1: polyvinyl alcohol 134 (2%); monostearatacylglycerol (0.5%); phytic acid (0.05%); sorbitol (0.05%); sodium alginate (0.1%); absolute alcohol (8%): No.2: polyvinyl alcohol 134(1%); soluble starch (1%); glucose (1%); sucrose (1%); sodium alginate (0.1%); sorbitol (0.05%)] gave the best effects on strawberry quality and shelf‐life. All treatments (Nos 1–4) were obviously superior to check experiments for soluble sugar, ascorbic acid, acidity and anthocyanin. Furthermore, the treatments gave superior results for browning index, commodity ratio and permeability of the cell membrane. Copyright © 2006 John Wiley & Sons, Ltd.     

Production and Application of Active Packaging Film with Ethylene Adsorber to Increase the Shelf Life of Broccoli (Brassica oleracea L. var. Italica)

Broccoli (Brassica oleracea L. var. Italica) florets were packaged in low‐density polyethylene (LDPE) bags with or without ethylene adsorber under passive modified atmosphere and then stored at 4°C for 20 days. LDPE films with (8% Tazetut® masterbatch, M2) or without ethylene adsorber (M1) were tested. The effects of modified atmosphere packaging treatments on gas concentrations (O₂, CO₂ and ethylene) in the headspace, the mass loss, colour, texture, pH, total soluble solids, chlorophyll content, total phenolic content and sensory quality of packaged broccoli were determined by comparing with unpackaged (control) florets. Results revealed that deterioration occurred quickly in control broccoli, manifested mainly by mass loss, chlorophyll degradation and stem hardening. Also, it was found unacceptable by sensory panel after 5 days. Conversely, in those florets packaged under modified atmosphere packaging, especially for LDPE with ethylene adsorber (M2), all changes related with loss of quality were significantly reduced and delayed with time. Additionally, total soluble solids and total phenolic content remained almost unchanged during the whole period. Ethylene concentration was determined as 61.8 ppm in M1 and 0.33 ppm in M2, respectively, at the end of the storage. Thus, broccoli packaged with M2 films had prolonged storability up to 20 days with high quality attributes, this period being only 5 days in unpackaged control broccoli. Oxygen concentration decreased below 1% after 5 days of storage in M1, and the shelf life of broccoli in these bags was limited to 5 days because of risk for anaerobic fermentation. Copyright © 2013 John Wiley & Sons, Ltd.     

Effect of chitosan coating and vacuum packaging on the quality of refrigerated grilled pork

The effects of chitosan coating and vacuum packaging on the quality and shelf‐life of retail packaged grilled pork in a PVDC/nylon pouch during refrigerated storage at 2 ± 1°C were investigated. Grilled pork without chitosan coating and packaged in 100% air was used as the control sample. Firmness, pH, colour, peroxide values, microbial population and shelf‐life (as determined by sensory characteristics) of the samples were determined during the storage. The results showed that colour, peroxide values and microbial population coincided with sensory characteristics. The delayed growth of microbes in vacuum packaging can be attributed to inhibition by low levels of O₂. Chitosan coating was shown to minimize oxidation, as reflected by the peroxide values, colour changes and microbial counts of the samples. Vacuum‐packaged chitosan‐coated grilled pork showed negligible microbial growth and was found to be organoleptically acceptable throughout the storage period. Chitosan coating along with vacuum packaging provided a type of active packaging to maintain quality and extend the shelf‐life of grilled pork. Copyright © 2006 John Wiley & Sons, Ltd.     

Microbiological,colour and sensory properties of fresh beef steaks in low carbon monoxide concentration

Steaks from gluteus medius m. (GM) and longissimus dorsi m. (LD) were packaged in atmospheres containing two low levels of CO (0.2 and 0.4%) in combination with 21% O₂ or without oxygen. The other components of the modified atmosphere packaging systems were carbon dioxide (30%) and nitrogen (balance). Steaks were evaluated on 0, 7, 14 and 21 days of storage at about 2^oC to investigate the effects of the gas mixtures on the microflora, instrumental (CIE L*a*b*) and visual colour and odour. The preservation of colour and odour of GM and LD steaks packaged under low carbon monoxide was best achieved using anoxic mixtures containing 0.2% CO and 30% CO₂. Steaks packaged without oxygen retained a desirable colour and practically did not present a visible discoloration or perceptive off‐odour along the entire storage time. Colour stabilization with 0.2% CO and 30% CO₂, without O₂, following storage up to 21 days at 2°C did not increase microbial risk of products. The increase in CO from 0.2 to 0.4% had a negative effect on the colour of LD steaks which was regarded as ‘artificial’ by some panellists. The higher stability achieved in this study using 0.2% CO may result from increased stability of the colour from Bos indicus × Bos Taurus cross. Discoloration and off‐odour were evident in the GM and LD steaks packaged aerobically after 14 days of storage when the counts of deteriorant bacteria achieved approximately 6.5 to 9.7 log CFU/g. Highest bacteriostatic effect could be obtained if the volume of injected CO₂ was sufficient to saturate the meat and keep in balance around the product during storage. Copyright © 2010 John Wiley & Sons, Ltd.     

Development of an active polylactic acid (PLA) packaging film by adding bleached bagasse carboxymethyl cellulose (CMCB) for mango storage life extension

This study aimed to determine the properties of a new active packaging film in order to extend the storage life of fresh mangoes by packing “Nam Dok Mai” mangoes (Mangifera indica Linn) with an active packaging film composed of biodegradable polymer and cellulose derivatives. A new packaging bag was produced primarily by blending polylactic acid (PLA) with spray‐dried carboxymethyl cellulose (CMC) from bleached bagasse (CMC_B) at various concentrations (0%, 1%, 2%, and 4% w/w). The film thickness of the PLA and PLA/CMC_B bags was 75 μm. Unpacked mangoes were used as control before the packaged ones were stored at export conditions (13 ± 1°C and 90 ± 5% relative humidity [RH]) to evaluate the efficiency of the PLA/CMC_B film. Mango respiration and ethylene production rate were measured periodically in a packaging atmosphere as an indicator of ripeness. Changing fruit physio‐chemistry parameters were also studied, including weight loss, peel and flesh colour, firmness, total soluble solid (TSS), and total acidity (TA). The capacity of PLA/CMC_B packaging to absorb water vapour and prolong mango shelf life was demonstrated, and active packaging function by control of RH was also demonstrated. The absorption of PLA/CMC_B packaging was increased dramatically at 4% (w/w) CMC_B mixed with PLA. At this CMC_B concentration, the packaging film could extend the shelf life of mangoes for 42 days in export condition as well as decrease the physio‐chemistry parameters and respiratory rate, which were significantly enhanced when compared with those of control mangoes or unpacked mangoes (P ≤ 0.05), which had a shelf life of approximately 3 weeks.     

Maintaining quality of fresh strawberries through various modified atmosphere packaging

The influence of various modified atmosphere packaging (MAP) (21/0.05, 4/8 and 60/20% O₂/% CO₂) on fresh strawberry qualities [pH, acidity, °Brix, colour ( L, a ) and texture profile analyses] was investigated and compared during storage. Among the gas combinations used, pH of fresh strawberry was 3.281 at 1 day, and increased to 3.561 for air [21/0.05% (O₂/CO₂)], 3.53 for low (4/8) and 3.538 high (60/20) at 12 days. At the end of the storage, °Brix had evolved from the initial 7.07 to 5.47, 5.65 and 5.62 for 21% O₂; 4% O₂ and 60% O₂, respectively. Storage in 60% O₂ or 4% O₂ delayed the decrease of °Brix, titratable acidity and increased pH compared with 21% O₂. At the end of the storage, the strawberry L values had slightly decreased. Initial values of the firmness were 1067 gf and reduced to 501 gf (21% O₂); 613 gf (4% O₂) and 575 gf (60% O₂) at 12 days storage. Higher O₂ resulted in better springiness and chewiness than those treated with 4% O₂ and 21% CO₂, but did not significantly affect resilience. These results show that the use of various MAP gas compositions, including high oxygen, could be a good alternative to maintain fresh strawberry qualities for at least 12 days. Copyright © 2008 John Wiley & Sons, Ltd.     

Shelf life extension of fresh asparagus using modified atmosphere packaging and vacuum skin packaging in microwavable tray systems

Asparagus (Asparagus officinalis L.) is one of the most popular vegetables because it contains a wealth of fiber and several essential nutrients. It is a very perishable commodity due to its very high respiration rate. To maintain product quality and to satisfy consumer demand as a convenient food, modified atmosphere packaging (MAP), vacuum skin packaging (VSP), and microwaveable containers were used to extend the shelf life of fresh-cut asparagus as a ready-to-eat food product. The objective of this study was to determine the shelf life of fresh-cut asparagus packed in MAP and VSP microwaveable tray systems at commercial storage conditions, 4°C, 80% RH. Weight loss, moisture content, O₂/CO₂ concentration in the package headspace, product pH, microbial growth, and sensory evaluation were used to determine the product quality and shelf life. Moreover, the preference of product appearance and the quality of the cooked asparagus in both microwaveable tray systems at different cooking times and microwave power levels was also sensorially evaluated. During storage for 21 days, there was no significant difference (p > 0.05) in weight loss, moisture content, and pH. Sanitation and packaging techniques also helped to retard the microbial growth. Both techniques, combined with refrigeration, help to maintain the freshness and product shelf life up to 21 days for MAP and 18 days for VSP. On the basis of hedonic scale results, consumers preferred the appearance of both packaging types. Both microwavable tray systems, thus, can help to prolong the shelf life of fresh-cut asparagus and can be eaten directly from the package.     

Modified Atmosphere Packaging of Guava Fruit

Fully matured fresh guava fruits (Lucknow‐49) were precooled at 10 °C for 1 h and pretreated with 500‐ppm benomyl for 5 min. The fruits were packed in 25‐µm and 50‐µm LDPE bags with active modified atmosphere packaging of 3% O₂ + 5% CO₂, 6% O₂ + 5% CO₂ and 9% O₂ + 5% CO₂ gas concentrations and stored at 5 ± 1 °C and 10 ± 1 °C temperatures as well as non‐packaged as control. The shelf life of guava could be increased up to 42 days by packaging in 50‐µm LDPE bags with a gas concentration of 9% O₂ + 5% CO₂ and stored at 10 °C without much change in physical, biochemical and sensory characteristics. Physico‐chemical changes viz., PLW, pulp to peel ratio, firmness, TSS, total sugar, ascorbic acid and titratable acidity were observed minimum for fruits packed in 50‐µm LDPE bags at 3% O₂ + 5% CO₂ gas concentration at 5 °C storage temperature, but sensory score decreased drastically after 21 days of storage. Chilling injury was observed for the fruits packed at 5 °C storage temperature after 21 days of storage, and it was severe in 25‐µm LDPE bag at later stage. Control fruits over‐ripened with the highest weight loss (12.47%) on 6 days of storage and discarded from the storage. Copyright © 2014 John Wiley & Sons, Ltd.