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.     

Prediction of plastic film thickness based on gas permeability and validation with ‘Kyoho’ table grapes for optimal modified atmosphere packaging

Modified atmosphere packaging (MAP) storage has become a useful technique for extending the shelf life of fruit and vegetables. However, the success of MAP depends on many factors, including types of fresh products, storage conditions, and the characteristics of the packaging films. To achieve the optimal gas composition in the package headspace and improve the postharvest quality of fresh produce, the packaging film with appropriate barrier properties needs to be selected. This study aimed to predict the film thickness by applying produce respiration rate and package film permeability data measured in given product weight and storage conditions. An available film (eg, 25‐μm‐thick low‐density polyethylene) was used to pack fresh produce, and the respiration rate of fresh produce and in‐package O₂ and CO₂ concentrations at steady state were measured. Permeability of the film was calculated based on mass balance, and the thickness of the film could be predicted if the recommended target O₂ and CO₂ concentration was obtained from the literature. To validate the predicted thickness value, an experiment was conducted by packaging fresh table grapes in bags of the predicted thickness. The effect of packaging with different film thicknesses on the quality of the fruit was determined. The results showed good agreement between the predicted and the experimental in‐bag O₂ and CO₂ concentrations, and the MAP with predicted thickness (90 μm) film was more effective in maintaining postharvest quality of grapes during low‐temperature storage than the thinner films (30 and 60 μm) and the control.     

Combined effect of chill storage and modified atmosphere packaging on mussels (Mytilus galloprovincialis) preservation

Changes in biochemical indices, microbial growth, headspace and sensory quality of mussels which had been packaged in two modified atmospheres [Modified atmosphere packaging (MAP) 1: 60% CO₂/20% N₂/20% O₂ and MAP 2: 60% CO₂/40% N₂] and under vacuum (VP) were studied for 14 days. The results showed better quality retention and greater shelf life of mussels packaged under MAP 1 as compared to MAP 2 and VP samples. Increase in total volatile basic nitrogen followed the order: MAP 1 < MAP 2, VP < air (control) samples while increase in trimethylamine nitrogen followed the order: MAP 1 < air < MAP 2 < VP. The 2‐thiobarbituric acid (TBA) values of MAP 1 and air samples were significantly higher (p < 0.05) than the TBA values of VP and MAP 2 samples. MAP 1 showed a greater (p < 0.05) inhibition effect on total viable count of mussel samples than all other packaging conditions. Based primarily on odour scores, the MAP 1 samples remained acceptable up to ca. 10–11 days, the MAP 2 and VP up to ca. 7–8 days while the air‐packaged samples up to ca. 5–6 days of storage. Copyright © 2007 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.     

Evaluation of Antimicrobial Active Packaging to Increase Shelf Life of Gluten‐Free Sliced Bread

This paper presents a complete study and comparison of the efficiency of three types of packaging system: active packaging, modified atmosphere packaging (MAP) and combinations of both. To choose the best option, we must take into account microbiological results as well as sensory quality; therefore, a complete sensory study and an in‐depth statistical study were carried out, in order to evaluate each option and their interactions. The results showed that active packaging considerably increases the shelf life of packaged food, so it could be an attractive option to extend the shelf life. The active packaging provided better sensorial properties than the MAP option. Positive factors like characteristic flavour and spongy texture had higher values in the absence of MAP, and negative properties like cinnamon flavour, crumbly texture and hardness reached higher values when MAP was present in the packaged food. So when microbiological and sensorial properties are taken into account, the active packaging is a better option than MAP to increase shelf life because it inhibits microbial growth while maintaining the high quality of sensorial properties for gluten‐free breads. Copyright © 2011 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.     

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.     

Combined effects of hot water treatment (HWT) and modified atmosphere packaging (MAP) on quality of tomatoes

Effects of hot water treatment (HWT) and modified atmosphere packaging (MAP) on quality of tomatoes were studied. Prior to packaging with low‐density polyethylene (LDPE) film (0.02 mm in thickness), tomatoes were immersed in hot water (42.5°C) for 30 min. Control tomatoes were not treated and were stored for 2 weeks at 10°C and then for 3 days at 20°C without packaging. Steady states of O₂ and CO₂ concentrations inside the package were about 5 and 8%, respectively, and were reached after 6 and 4 days of storage, respectively. MAP reduced weight loss of tomatoes to about 41% of that of unpackaged fruit during a 2‐week storage period. The use of a combination of HWT and MAP reduced weight loss and decay, inhibited color development and maintained firmness of tomatoes but had no effect on soluble solids content or titratable acidity. HWT slightly reduced mold growth of tomatoes stored in MAP. Packaging of control fruit in MAP resulted in stimulation of mold growth around the stem end of the fruit after about 1 week of storage and also resulted in cracking and decay. HWT could be used as disinfectant for tomatoes prior to storage in MAP in order to reduce microbial growth, cracking and decay that may be caused by excessive water vapor inside the package. Copyright © 2003 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.     

Quality changes of treated fresh‐cut tropical fruits in rigid modified atmosphere packaging containers

There has been increasing demand for various fresh‐cut tropical fruits. However, their short shelf‐life has limited the market increase of this product. Quality changes (firmness, colour, total soluble solids (TSS), titratable acidity (TA), sensory quality and microbial safety) of fresh‐cut mangoes, pineapples, melons and mixes of these fruits were evaluated. Chemical treatments to reduce browning, firmness loss and decay of fresh‐cut tropical fruits were investigated. The most effective agents for fresh‐cut mangoes, pineapples and melons were 0.1m ascorbic acid, 0.2m ascorbic acid and 0.2m ascorbic acid + 0.2m calcium chloride, respectively. Fresh‐cut tropical fruits were packaged in various rigid containers (PET, OPS and OPLA). Gas composition in the package headspace and time to reach steady‐state condition varied among fresh‐cut packaging systems and affected their quality and shelf‐life. The effects of package permeability of O₂ and CO₂ on quality and shelf‐life of the fresh‐cut products are discussed. Extended shelf‐life was observed in fresh‐cut mangoes, pineapples and mixes packaged in PET due to reduced O₂ and elevated CO₂ atmosphere. A modified atmosphere of 6% O₂ and 14% CO₂ achieved in PET extended the shelf‐life of fresh‐cut pineapples from 6 to 13 days. Accumulation of CO₂ may impart an off‐odour of fresh‐cut fruits. The results suggested that the shelf‐life of fresh‐cut fruits could be extended by using proper rigid containers. Suitable mixes to create optimal equilibrium modified atmosphere had a potential to extend shelf‐life of short shelf‐life fresh‐cut tropical fruits. Copyright © 2006 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.     

Assessment of oxygen levels in convenience‐style muscle‐based sous vide products through optical means and impact on shelf‐life stability

An optical oxygen analyser was used in two small‐scale industrial trials to non‐destructively assess the quality of packaged convenience foods and packaging process. Beef lasagne packed under 70% vacuum and cooked under standard sous vide conditions was monitored for residual oxygen, using disposable sensors incorporated in each pack and a benchtop optical oxygen analyser. High levels of residual oxygen close to ambient were determined in the majority of packs after packaging, as opposed to anticipated levels of 4–5%. Residual oxygen was monitored over product shelf‐life (4 weeks at +4–10°C) along with measurement of microbial growth and lipid oxidation in food by conventional destructive methods. Oxygen levels in packs went down to almost zero between weeks 2 and 3 indicating deterioration of packaged product. Correlation between oxygen profiles and the rate of microbial growth and lipid oxidation was established. The optical oxygen sensor system was shown to provide valuable information about performance of the packaging process, product storage conditions and food quality in a convenient and cost‐efficient fashion and non‐destructively. Copyright © 2004 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.     

Comparison of Various Packaging Films for Mango Export

This study compared the effects of the use of various types of packaging films in maintaining quality, preserving bioactive compounds and extending shelf life of the ‘Nam Dok Mai’ mango. The principal techniques for maintaining the quality of mangoes are based on modified atmosphere packaging using highly gas‐permeable films and an ethylene‐removing mechanism. The films studied were non‐perforated highly gas‐permeable film, non‐perforated ethylene‐absorbing highly gas‐permeable film (HNPE), micro‐perforated highly gas‐permeable films (HMP) and common non‐perforated polyethylene film (LNP). These films were compared with non‐packaging treatment, which served as a control (C). Gas composition (O₂, CO₂ and C₂H₄) in the package headspace was monitored during storage at 12°C. The quality of mangoes were assessed by weight loss, colour (L* a* b*), texture, total soluble solids, titratable acidity, total phenolics, total flavonoids, ethanol concentration and sensory quality. Equilibrium‐modified atmospheres of 5 kPaO₂ + 5 kPaCO₂ and 4 kPaO₂ + 5 kPaCO₂ were achieved in the non‐perforated highly gas‐permeable film and HNPE packs, respectively. Carbon dioxide accumulation was observed in the HMP and LNP packs where CO₂ reached 17 and 10 kPa, respectively, after storage for 10 days. The shelf life of mangoes was extended to 40 days with HNPE, 35 days with HNP, and 30 days with HMP, as compared with 20 days with control and 5 days with LNP. HNPE, the film incorporated with fine particles of mordenite framework inverted‐type zeolite with ethylene‐absorbing ability, could further extend the shelf life of mangoes in addition to modified atmosphere packaging alone. Copyright © 2011 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.     

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.     

Modelling a modified atmosphere packaging system for fresh scallops (Argopecten purpuratus)

Seafood is a highly perishable food, which has a relative short shelf‐life. Modified atmosphere packaging (MAP) is a system that offers a way of extending the shelf‐life of seafood products, maintaining quality and inhibiting bacterial growth. The objective of this research was to study and determine the optimal conditions for packaging scallops in a modified atmosphere system, which includes CO₂/O₂/N₂ mixture, headspace:food ratio and storage temperature, utilizing an integrated mathematical model for MAP systems with its respective experimental validation. For validation purposes, two experiments were conducted, using gas mixtures of: (a) 45% CO₂/10% O₂/45% N₂; and (b) 60% CO₂/10% O₂/30% N₂. In addition, two experiments, at 6°C and 20°C, were conducted to obtain the shelf‐life model, utilizing the following gas mixtures: 30% CO₂/10% O₂/60% N₂; 45% CO₂/10% O₂/45% N₂; 60% CO₂/10% O₂/30% N₂; and 75% CO₂/10% O₂/15% N₂. Gas mixtures with CO₂ concentrations between 30% and 70% and different headspace:food ratios were tested during simulations. The optimal conditions for scallop storage were a 60% CO₂/10% O₂/30% N₂ gas mixture and a headspace:food ratio of 2:1. With these conditions, a simulated shelf‐life of 21 days was obtained. Optimal conditions consider maximum shelf‐life, an adequate film collapse criterion, and time to reach the pseudo‐equilibrium condition. The predictive mathematical model, coupled with experimental studies for specific products, can be efficiently utilized to evaluate packaging alternatives (size, material and selected thickness) for different temperatures and initial gas concentration scenarios of MAP products. Copyright © 2006 John Wiley & Sons, Ltd.     

Effects of polylactic acid antimicrobial films on preservation of Chinese rape

Two antimicrobial agents of organic salicylic acid (SA) and inorganic nanosized titanium dioxide (TiO₂) were added into polylactic acid (PLA) respectively to prepare two different biodegradable packaging films. The antimicrobial properties of PLA-based films were then characterized and the film preservation effect on fresh vegetables had been exampled by evaluating the external appearance, headspace gas concentration, weight loss rate, decay rate and −a/b values of Chinese rape. The results showed that the antimicrobial rate of PLA/4%TiO₂ film was 91.3% against Staphylococcus aureus and 90.8% against Escherichia coli. In the case of PLA/6%SA film, its antimicrobial rate was 97.3% against S. aureus and 93.1% against E. coli. These two antimicrobial films were seen to obviously reduce the respiration rate of Chinese rape and exhibit lower decay rate and higher −a/b values of Chinese rape than those packaged in pure PLA bag, resulting in the extended shelf life for stored Chinese rape. These satisfactory performances suggest that the PLA-based antimicrobial films could be potentially suitable for the preservation of green vegetables.     

The Applications of ‘active packaging and chlorine dioxide’ for extended shelf life of fresh strawberries

Fresh strawberries are highly perishable because of their high respiration rates. Three alternative packaging approaches were investigated to maintain the high quality and to extend the shelf life of strawberries. These were active packaging using chlorine dioxide (ClO₂) and ethylene‐moisture sachets. The quality properties of four groups of samples were measured over 3 weeks at 4°C. The groups were: control, active packaging without ClO₂ treatment, active packaging with low‐dose (5 ppm) ClO₂ treatment and active packaging with high‐dose (10 ppm) ClO₂ treatment. Measured properties were weight loss, gas concentration, pH, titratable acidity (TA), soluble solids content, texture profile and colour. Active packaging with low‐dose (5 ppm) ClO₂ treatment was found to be the most effective for TA retention and for maintaining (L) brightness values. The control group showed the largest total soluble solids reduction from 7.60 to 6.57. Active packaging without ClO₂ treatment showed the lowest weight loss (0.33%), while the control group showed the highest (1.86%) at the end of the storage. Active packaging with high‐dose ClO₂ treatment showed the highest preference value in global appearance, colour and firmness properties. The low‐ and high‐dose active packaging groups had greater firmness, gumminess and chewiness than that of all other treatments. The results from this study showed that active packaging treatment with ClO₂ and the ethylene‐moisture sachets had a beneficial effect on the quality of strawberries and could be used commercially. Copyright © 2010 John Wiley & Sons, Ltd.