New strategies for minimally processed cactus pear packaging

This work presents a preliminary study on the packaging procedures to prolong the shelf life of minimally processed cactus pears. In particular, different packaging strategies were tested by combining coating and hydro-gels to different polymeric materials. Monitoring headspace gas concentrations, viable cell load of main spoilage microorganisms, sensory characteristics and weight loss, the quality decay in each packaging system was assessed. Results showed that the immersion of fresh-cut fruit into both hydro-gels strongly reduced the shelf life, most probably due to water migration from the surrounding hydro-gel to the crop. On the contrary, the coating prolonged the shelf life of the minimally processed fruit to about 13 days, corresponding to an increase of about 40%, compared to the control sample. Results also suggested that the barrier properties of the selected films did not affect greatly the quality of the coated fresh-cut produce.Industrial relevanceThe market of ready-to-eat fruit has grown rapidly in recent years. As a consequence, there is an emergent call for finding new preservation strategies to prolong the shelf life of minimally processed food, without compromising human and environmental safety. The results of this work dealing with minimally processed cactus pears represented an interesting goal with potential industrial applications. In fact, this paper combined the effectiveness of a natural coating applied to fresh-cut fruit to the performance of a bio-based polymeric packaging film.     

Different packaging strategies for fresh-cut 'barattiere' melon cultivar (cucumis melo L.)

Optimising packaging for minimally processed 'Barattiere' melon cultivar ( Cucumis melo L.) is addressed in this work. Melon slices were dipped in water solution containing ascorbic acid (1%) and calcium chloride (0.2%). Dipped and untreated fresh-cut produce was packaged in four different polymeric materials (two biodegradable films, a commercially available multilayer film (MLF) and polypropylene), before storing at 5 °C. During storage, headspace gas composition, microbial quality, pH and mass loss were monitored for a period of 2 weeks. Results suggest that film characteristics strongly influenced gas concentrations in the headspace, microbial growth and weight. Among the tested packaging materials, the MLF seemed to delay significantly the detrimental phenomena involved in quality acceptance, even if clearly anaerobic atmospheres were recorded. The biodegradable films, combined with a dipping pre-treatment, could represent a good compromise between film performance and environmental impact.     

Influence of different packaging systems on fresh-cut zucchini (Cucurbita pepo)

In this work different packaging strategies aimed to prolong the shelf life of minimally processed zucchini are presented. In particular, two different cultivars (Sofia and Diamante) were tested. The sliced zucchini were packaged in oriented polypropylene-based (OPP) bag and into a bio-polymeric film (COEX) under passive and active MAP. The investigated produce was stored at 5 °C for approximately 9 days. Headspace gas concentrations, pH, mass loss, sensory quality and viable cell load of main spoilage microorganisms were monitored for the entire observation period. In order to determine the respiration activity, O₂ and CO₂ concentrations were monitored not only in OPP and COEX packages but also in the headspace of an aluminum-based package. Results suggested that for Diamante cultivar OPP film under active and passive MAP showed slightly better performances in prolonging the shelf life, compared to COEX film; instead, for Sofia cultivar better results were obtained with OPP film only under active MAP conditions.Industrial relevanceThis paper suggests an effective packaging solution to delay the quality decay kinetic of two cultivars of fresh-cut zucchini. Due to changes in consumer attitudes, the proposed mild strategies to prolong the shelf life of ready-to-cook products could really gain widespread acceptance by industry of the minimally processed food sector. Due to great attention to the environmental pollution a biodegradable packaging system was also studied and compared to the common polypropylene-based film, even though the characteristics of this specific produce could not suggest the substitution with traditionally used plastic materials with eco-friendly polymers.     

Cassava Starch Coating and Citric Acid to Preserve Quality Parameters of Fresh-Cut “Tommy Atkins” Mango

Abstract: Combination of citric acid dipping (5 g/L) and cassava starch coating (10 g/L), with and without glycerol (10 g/L), was studied to verify the effectiveness of these treatments to inhibit enzymatic browning, to reduce respiration rate, and to preserve quality parameters of “Tommy Atkins” fresh-cut mangoes during storage at 5 °C. Color characteristics (L* and C*), mechanical properties (stress at failure), weight loss, β-carotene content, sensory acceptance, and microbial growth of fruits were evaluated during 15 d. The respiration rate of fruit subjected to the treatments was also analyzed. Nontreated fresh-cut mango was used as a control sample. Cassava starch edible coatings and citric acid dipping promoted a decrease in respiration rate of mango slices, with values up to 41% lower than the control fruit. This treatment also promoted better preservation of texture and color characteristics of mangoes and delayed carotenoid formation and browning reactions during storage. Moreover, the treated fruit showed great sensory acceptance by consumers throughout the whole storage period. However, the use of glycerol in the coating formulation was not efficient in the maintenance of quality parameters of fresh-cut mangoes, promoting a higher weight loss of samples, impairing fruit texture characteristics, increasing carotenogenesis, and favoring microbial growth during storage. Practical Application: Consumer demand for tropical fresh-cut products is increasing rapidly in the world market. Fresh-cut mangoes are appreciated world-wide for its exotic flavor. However, its shelf life is limited by changes in color, texture, appearance, off-flavors and microbial growth. The edible coatings act as gas and water vapor barrier, extending the storage time of fresh-cut fruit and vegetables. Thus, cassava starch is an alternative to preserve minimally processed mangoes and the quality parameters of fresh fruit. The information of this work is useful for the fresh-cut produce industry to increase shelf life of fresh-cut mangoes, which can be considered an alternative to fast food and other ready-to-eat products, attending the demand for healthy and convenient foodstuffs.     

Effect of cassava starch coating on quality and shelf life of fresh-cut pineapple (Ananas comosus L. Merril cv "Pérola")

This research studied the influence of treatment with ascorbic acid, citric acid, and calcium lactate dipping and cassava starch edible coatings on quality parameters and shelf life of fresh-cut pineapple in slices during 12 d at 5 °C. After previous tests, the treatments selected for this study were samples dipped into antibrowning solution with 0.5% of ascorbic acid and 1% of citric acid, with and without 2% of calcium lactate and coated with 2% of cassava starch suspensions. Changes in weight loss, juice leakage, mechanical properties (stress at failure), color parameters (L* and H*), ascorbic acid content, sensory acceptance, and microbial growth of fruits were evaluated. Samples only treated with antibrowning agents were used as control. Edible coatings with and without calcium lactate were efficient in reducing weight loss, juice leakage, and maintaining firmness during storage. However, these samples showed more browning and the ascorbic acid content was reduced. All treatments presented good sensory acceptance (scores above 6). The determining factor of shelf life of pineapple slices was the microbial spoilage. A shelf life of 8 d was obtained for pineapple slices only treated with antibrowning agents. On the other hand, coated samples showed a reduced shelf life of 7 d and higher yeast and mold growth. Thus, although cassava starch coatings were efficient in reducing respiration rate, weight loss, and juice leakage and maintained mechanical properties, these treatments were not able to increase the shelf life of minimally processed pineapple. Practical Application: Pineapple fruit is highly appreciated for its aroma, flavor, and juiciness, but its immediate consumption is difficult. Therefore, pineapple is a potential fruit for minimal processing. However, shelf life of fresh-cut pineapple is very limited by changes in color, texture, appearance, off-flavors, and microbial growth. The use of edible coatings as gas and water vapor barrier and antibrowning agents can extend the storage time and maintain the quality of fresh-cut produce. Cassava starch and alginate coatings are alternative to preserve minimally processed pineapples without changing the quality parameters of fresh fruit. Thus, this study is useful for consumers and fresh-cut industry interested in knowing factors affecting shelf life and quality of fresh-cut pineapple.     

Fresh cut ‘Tommy Atkins’ mango pre-treated with citric acid and coated with cassava (Manihot esculenta Crantz) starch or sodium alginate

This work aimed to evaluate quality parameters of ‘Tommy Atkins’ mango slices pre-treated with citric acid and cassava starch or sodium alginate edible coatings, with or without glycerol. Samples only treated with citric acid were also evaluated. Mango slices dipped in sanitising solution were used as control. Colour parameters, mechanical properties, weight loss and respiration rate were analysed during 15 days at 5 °C. Cassava starch coating, with or without glycerol, provided higher stress at failure and lightness values than control sample throughout storage (p ≤ 0.05). The citric acid promoted colour preservation, but increased significantly samples weight loss during storage. Sodium alginate coatings did not maintain quality characteristics, showing stress at failure and lightness values lower than control after 15 days. All coatings reduced respiration rate, but citric acid dipping and cassava starch coating without glycerol treatments were more effective, reaching values around 41% lower, when compared to control sample.

Industrial Relevance

Fresh-cut mangoes are appreciated world-wide for its exotic flavour and nutritional composition. However, their shelf life is limited by changes in colour, texture, appearance and microbial growth. The edible coatings act as gas and water vapour barrier, extending the storage time of fresh-cut fruit and vegetables. Thus, cassava starch and alginate are alternatives to preserve minimally processed mangoes, maintaining the quality parameters of fresh fruit. This work is useful for the minimal processing industry in order to increase shelf life of fresh-cut mangoes, which can be considered an alternative to fast food and other ready-to-eat products, attending the demand for healthy and convenient foodstuffs.     

Evaluation of Zein Films as Modified Atmosphere Packaging for Fresh Broccoli

ABSTRACT: Modified atmosphere packaging (MAP) is increasingly used with minimally processed produce. Increased MAP usage coupled with negative environmental views associated with nondegradable synthetic packaging materials creates a need for biodegradable films. Zein films plasticized with oleic acid had been proposed for biodegradable packaging applications. Conversion treatments including lamination and coating films with tung oil were reported to improve water vapor and gas barrier properties of films. In this work, the ability of treated and untreated zein films to perform as MAP for fresh broccoli florets was investigated. Florets were packaged in glass jars sealed with zein films and stored under refrigeration for 6 d. Headspace oxygen and carbon dioxide concentrations were monitored during storage. Tested films allowed the development of modified atmospheres inside the packages. Broccoli florets packaged in the test films maintained their original firmness and color.     

The effect of packaging treatment on the storage quality of minimally processed bunched onions

Storage quality of minimally processed (MP) bunched onions, as affected by plastic film packaging, was investigated to determine the optimum packing method for this vegetable product. Five different packaging treatments, including two passive modified atmosphere packaging (MAP), two active MAP and a moderate vacuum packaging (MVP), were used for MP bunched onions. Quality attributes of the samples were evaluated periodically in terms of weight loss, colour, decay ratio, microbial counts and sensory properties during storage at 10 °C for 28 days. Various sealed‐packaging treatments did not significantly influence changes in colour of white stem and green leaf tissues, flesh weight loss and microbiological populations including mesophiles, psychrotrophs and lactic acid bacteria. However, sensory attributes and disease incidence were affected by packaging type. MVP with a gas‐permeable plastic film retained better quality bunched onions, with reduced microbial decay and visual sensory aspects, as compared with the other packages.     

Combined effect of active coating and MAP to prolong the shelf life of minimally processed kiwifruit (Actinidia deliciosa cv. Hayward)

In this work different strategies aimed to prolong the shelf life of minimally processed kiwifruits are presented. First, the effectiveness of several treatments in delaying the quality loss of the investigated produce packaged under passive MAP was addressed; afterward, the treatments that have shown the best performances were used to assess the effectiveness of active MAP in prolonging the packaged produce shelf life. Different treatments such as coating with sodium alginate in combination with dipping into an hydro-alcoholic solution (Coat-dipp-EtOH), dipping into an hydro-alcoholic solution (Dipp-EtOH) and coating with sodium alginate containing grape fruit seed extract solution (Coat-GFSE) were investigated. The untreated samples were used as control. Headspace gas concentrations, pH, mass loss, sensory quality and viable cell load of main spoilage microorganisms were monitored in both the experimental steps. Results suggested that the best performances under passive MAP were recorded with the coating treatments, justifying the choice of this treatment in the second step. In fact, the coatings were more effective in delaying dehydration and slowing down respiratory activity of minimally processed kiwifruits both in passive and active MAP. The combination of active compounds with alginate-based coating delayed the microbial growth whereas the sole dipping treatment was inefficient. In particular, a viability loss of the mesophilic and psychrotrophic bacteria of about 2 log cycle for the coated samples with respect to control and dipped samples was found. However, as the microbial load was always found below the threshold value imposed by law, the sensorial acceptability limit of the packaged fresh-cut produce coincided with its shelf life. Alginate-based coating reduced respiratory activity, as well as sensory decay, increasing the sensorial acceptability limit of the samples packaged under passive MAP up to 12 days with respect to the control (8 days). For the samples packaged under active MAP, the coating treatments reduced the excessive dehydration of the produce due to the MAP conditions. In fact, when the active MAP was used alone a very short shelf life of the uncoated samples occurred (2.7 days). Whereas, the combined use of active MAP and coating treatments prolonged the produce shelf life up to 13 days.     

Shelf life of fresh-cut Cime di rapa (Brassica rapa L.) as affected by packaging

In this work, the effectiveness of different packaging in prolonging the shelf life of fresh-cut Cime di rapa (Brassica rapa L.) was addressed. Two subsequent experimental trials were run to investigate first the ability of different packaging materials (an oriented polypropylene, a blend of biodegradable polyesters and a nylon/polyethylene multilayer) in delaying the quality loss and then to assess the efficacy of modified atmosphere packaging (MAP). Two different combinations of gas were investigated, oxygen 10%, carbon dioxide 2% and nitrogen 88%, noted as MAP1 and oxygen 8%, carbon dioxide 2% and nitrogen 90%, noted as MAP2. Headspace gas concentration, weight loss, spoilage microbial growth, pH and sensorial quality were monitored in both sets of experiments. The results demonstrated that the best performances under ordinary atmosphere were recorded with the oriented polypropylene-based film, justifying the choice of this polymeric material in the second set-up. The tested MAPs exerted somewhat different results on product quality: the samples packaged under MAP1 recorded a shelf life of 14 days limited by visible moulds, whereas, fresh-cut leaves sealed under MAP2 highlighted a shelf life less than 9 days, due to a high proliferation of total mesophilic bacteria.     

Fresh-cut broccoli florets shelf-life as affected by packaging film mass transport properties

In this work, the influence of packaging film mass transport properties on the quality loss of fresh-cut broccoli florets is addressed. The work was divided into two subsequent experimental steps; first, the selection of potential packaging films was carried out by monitoring the headspace gas concentrations in package of broccoli. Then, the mass transport properties of some previous selected films were assessed on product shelf-life. To this aim, unpackaged fresh-cut broccoli and intact broccoli wrapped in polyvinyl chloride were used as controls. Headspace gas concentration, mass loss, sensorial quality and spoilage microbial growth were monitored. The micro-perforated films were the most effective in reducing mass loss, wilting and maintaining sensory quality for a longer period. In particular, the micro-perforated film that had the lowest OTR value showed the best performance in prolonging of the product shelf-life if compared to either control samples and fresh-cut broccoli packaged in the non-perforated film. The results highlighted that an approximately 50% shelf-life increase of fresh-cut florets broccoli compared to whole broccoli, and of about 30% respect to the unpackaged fresh-cut produce was obtained.     

Survival and growth of Listeria monocytogenes and enterohemorrhagic Escherichia coli O157:H7 in minimally processed artichokes

The ability of Listeria monocytogenes and Escherichia coli O157:H7 inoculated by immersion (at 4.6 and 5.5 log CFU/ g, respectively) to survive on artichokes during various stages of preparation was determined. Peeling, cutting, and disinfecting operations (immersion in 50 ppm of a free chlorine solution at 4 degrees C for 5 min) reduced populations of L. monocytogenes and E. coli O157:H7 by only 1.6 and 0.8 log units, respectively. An organic acid rinse (0.02% citric acid and 0.2% ascorbic acid) was more effective than a tap water rinse in removing these pathogens. Given the possibility of both pathogens being present on artichokes at the packaging stage, their behavior during the storage of minimally processed artichokes was investigated. For this purpose, batches of artichokes inoculated with L. monocytogenes or E. coli O157:H7 (at 5.5 and 5.2 log CFU/g, respectively) were packaged in P-Plus film bags and stored at 4 degrees C for 16 days. During this period, the equilibrium atmosphere composition and natural background microflora (mesophiles, psychrotrophs, anaerobes, and fecal coliforms) were also analyzed. For the two studied pathogens, the inoculum did not have any effect on the final atmospheric composition (10% O2, 13% CO2) or on the survival of the natural background microflora of the artichokes. L. monocytogenes was able to survive during the entire storage period in the inoculated batches, while the E. coli O157:H7 level increased by 1.5 log units in the inoculated batch during the storage period. The modified atmosphere was unable to control the behavior of either pathogen.     

Synergistic Effect of Sodium Chlorite and Edible Coating on Quality Maintenance of Minimally Processed Citrus grandis under Passive and Active MAP

Edible coating has been an innovation within the bioactive packaging concept. The comparative analysis upon the effect of edible coating, sodium chlorite (SC) and their combined application on quality maintenance of minimally processed pomelo (Citrus grandis) fruits during storage at 4 °C was conducted. Results showed that the combination of edible coating and SC dipping delayed the microbial development whereas the sole coating or dipping treatment was less efficient. The synergetic application of edible coating and SC treatment under modified atmosphere packaging (MAP, 10% O₂, 10% CO₂) was able to maintain the total soluble solids level and ascorbic acid content, while reduce the weight loss as well as development of mesophiles and psychrotrophs. Nonetheless, the N, O‐carboxymethyl chitosan solely coated samples showed significantly higher level of weight loss during storage with comparison to the untreated sample. Furthermore, the combined application of edible coating and SC dipping under active MAP best maintained the sensory quality of minimally processed pomelo fruit during storage.     

Innovative processes and technologies for modified atmosphere packaging of fresh and fresh-cut fruits and vegetables

Modified atmosphere packaging (MAP) technology has been commercially viable since the 1970s. Currently, MAP is extensively used worldwide to preserve the quality and extend the shelf-life of whole fresh fruits and vegetables, but is also increasingly used to extend the shelf-life of minimally processed fresh fruit and vegetables. This review discusses new processes and technologies that can be used to improve quality preservation and consumer acceptability of minimally processed produce where high respiration rates and challenging degradation processes operate. New packaging innovations are enabling producers and retailers to further maintain quality for longer. Innovative approaches to extend shelf-life include active MAP with differentially permeable films, films that incorporate antimicrobial properties, edible coatings that confer barriers properties, and the use of non-traditional gases to modify respiration. Intelligent packaging using integrated sensor technologies that can indicate maturity, ripeness, respiration rate and spoilage are also appearing. This review demonstrates that preservation technologies and associated packaging developments that can be combined with modified atmosphere are constantly evolving technology platforms. Adoption of combinations of technology improvements will be critical in responding to commercial trends towards more minimally processed fresh-cut and ready-to-eat fruit and vegetable products, which require specialized packaging solutions.     

The effect of edible coatings and polymeric packaging films on the quality of minimally processed carrots

Minimally processed carrots have a short shelf‐life because of white blush formation (caused primarily by surface dehydration) and microbiological spoilage (caused mostly by lactic acid bacteria). The use of polymeric packaging films combined with edible coatings might have an additive or synergistic effect to extend the shelf‐life of minimally processed carrots because of the formation of a double barrier to gases and water vapour. A 3 × 3 factorial experiment using a polymeric packaging film of three different levels of permeability and a cellulose‐based edible coating (Nature Seal^®) at different concentrations was conducted on minimally processed carrots to investigate any possible synergistic effect over 12 days of storage at 10 °C. No such effect was found. The polymeric packaging film effectively prevented microbiological growth and spoilage but was unable to control white blush formation. On the other hand, the edible coating partially controlled white blush formation but enhanced microbiological spoilage. The polymeric packaging film functioned primarily as a gas barrier, whereas the edible coating probably functioned as a moisture barrier. White blush formation was found to be the most important shelf‐life determinant for minimally processed carrots. Copyright © 2003 Society of Chemical Industry     

Color of Minimally Processed Potatoes as Affected by Modified Atmosphere Packaging and Antibrowning Agents

Minimal processing of potatoes was studied by using different treatments of cut potatoes in combination with modified atmosphere packaging. Different packaging materials and peeling methods were evaluated. An L-cysteine (0.5%) and citric acid (2%) mixture prevented browning of potatoes effectively. Active modification of the atmosphere inside the package was necessary to achieve extended shelf-life. Nitrogen flushing was more effective than other gas treatments with a highly permeable multilayered polyolefin packaging material. Hand peeling and lye peeling resulted in better quality, but abrasion peeling was undesirable for fresh potatoes. The shelf-life of the minimally processed products could be extended to nearly 3 wk under refrigerated storage.     

Physical and chemical changes in minimally processed green asparagus during cold-storage

The purpose of this research is to study effects of an innovative packaging method on the shelf-life of minimally processed green asparagus. The physical–chemical parameters analyzed (weight loss, colour, texture, chlorophyll and citric acid), and monitored by untrained panellists during the cold storage period at 6 °C, showed that pairing of a semi-permeable film with an adsorbent material and immersion in ascorbic acid solution were able to extend the shelf-life of green asparagus. Also, on the basis of the results obtained, a study of the chlorophyll and toughness degradation kinetics of green asparagus was conducted during cold storage. These data showed the toughening of asparagus spears to be faster than chlorophyll degradation. Thus, the former can be used as a reliable quality index to predict the shelf life of such products.     

包装薄膜对鲜切莴笋品质的影响

以普通塑料薄膜保鲜袋作对照,研究不同包装薄膜(0.03mm聚氯乙烯薄膜、0.03mm聚乙烯薄膜、0.03mm微孔薄膜)对鲜切莴笋贮藏期间品质的影响。结果表明:0.03mm厚聚乙烯薄膜包装能有效地控制鲜切莴笋的失重率、褐变度、呼吸强度、Vc损失率,提高鲜切莴笋的感官品质和营养价值。     

鲜切青笋防腐保鲜工艺的优化及不同包装材料对其品质的影响

为了研究不同防腐剂和不同包装材料对鲜切青笋防腐保鲜的效果,并延长其贮藏时间,通过预试验选择山梨酸钾、纳他霉素、柠檬酸为有效合适的防腐剂,按照L9(34)正交试验制作不同配比的防腐保鲜复合液,以鲜切青笋在贮藏过程中的细菌总数、失重率及硬度为测定指标,最终以综合评分确定最佳复合液配比。结果表明:防腐保鲜液的最佳配比为0.02%纳他霉素+2.0%柠檬酸+0.04%山梨酸钾。以普通塑料薄膜保鲜袋作对照,研究不同规格(0.07 mm、0.08 mm、0.09 mm)透气性的双向拉伸尼龙(BOPA)与低密度聚乙烯(LDPE)复合包装袋对鲜切青笋包装储藏期间的失重率、维生素C的含量、硬度的影响,并选择最佳的包装材料。结果表明:0.07 mm规格的复合材料包装鲜切青笋效果最佳。     

Effects of Ripeness Stages on the Storage Atmosphere, Color, and Textural Properties of Minimally Processed Apple Slices

ABSTRACT: Fruit maturity is a determinative factor in maintaining the original color and, to a greater extent, the texture of minimally processed fresh-cut apple slices. Mature-green apples (because of their lower respiration and ethanol formation) were the most suitable to process for extending post-cutting-quality shelf life. Sliced apples processed at an earlier stage of ripeness, but dipped in a solution of ascorbic acid (C₆H₈O₆) and calcium chloride (CaCl₂) and stored under 100% N₂, preserved their original color with minor changes. However, these processing and packaging treatments could not effectively prevent the apple slices from softening, and apple flesh underwent a progressive loss of firmness from 8.0 to 4.8 N.