Edible Active Coatings Based on Pectin,Pullulan, and Chitosan Increase Quality and Shelf Life of Strawberries (Fragaria ananassa)

Edible active coatings (EACs) based on pectin, pullulan, and chitosan incorporated with sodium benzoate and potassium sorbate were employed to improve the quality and shelf life of strawberries. Fruits were washed, disinfected, coated by dipping, packed, and stored at 4 °C for 15 d. Application of EACs reduced (P < 0.05) weight loss and fruit softening and delayed alteration of color (redness) and total soluble solids content. In contrast, pH and titratable acidity were not affected (P > 0.05) throughout storage, and ascorbic acid content was maintained in pectin‐EAC coated strawberries. Microbiological analyses showed that application of EACs reduced (P < 0.05) microbial growth (total aerobic counts, molds, and yeasts) on strawberries. Chitosan‐EAC coated strawberries presented the best results in microbial growth assays. Sensory quality (color, flavor, texture, and acceptance) improved and decay rate decreased (P < 0.05) in pectin‐EAC, pullulan‐EAC, and chitosan‐EAC coated strawberries. In conclusion, EACs based on polysaccharides improved the physicochemical, microbiological, and sensory characteristics, increasing the shelf life of strawberries from 6 (control) to 15 d (coated fruits).     

百里香酚/海藻酸钠膜对茄梨贮藏品质的影响

采用海藻酸钠(Sodium Alginate,SA,2%(m/v))和百里香酚/海藻酸钠(Thymol/Sodium Alginate,Thy/SA,Thy终浓度为40 mg/L)涂膜分别对茄梨进行处理,于20℃下进行贮藏,以果实硬度、可溶性固形物含量、抗坏血酸含量、可滴定酸含量、丙二醛含量、多酚氧化酶活性等指标来判断茄梨的品质变化。结果表明,Thy/SA涂膜使得茄梨果实的贮藏期由9 d(对照组)延长至18 d,有效延缓了果实硬度、可滴定酸、抗坏血酸和总酚含量的下降,以及可溶性固形物、丙二醛含量、多酚氧化酶和过氧化氢酶活性的上升。由此可见,Thy/SA涂膜可较好地维持贮藏过程中茄梨的果实品质,进而延长了其贮藏期。     

Effect of native and acetylated‐crosslinked waxy corn starch‐beeswax coatings on quality attributes of raspberries during storage

Edible coatings (ECs) are a thin layer of a mixture of edible materials, applied in the liquid state and dried over the surface of a food product to maintain its quality during storage. This work was aimed to study the effect of ECs made from wx corn starch (WCS) or acetylated cross‐linked starch (ACLS) added with beeswax on fresh raspberry quality attributes during short‐term cold storage. Freshly harvested fruits were coated, dried, packed in plastic trays and stored up to 8 days at 4°C. During storage quality parameters such as firmness, respiration rate, anthocyanins content, total phenols, color changes, and weight loss were evaluated. A clear effect on control of respiration rate was observed in coated raspberries. Respiration rate of uncoated fruit was 4.5 ± 0.28 mmol/kg/h and decreased to 4.2 ± 0.27 for ACLS and to 4.1 ± 0.08 mmol/kg/h for WCS‐coated raspberries, after 56 h of storage at 15°C. Ethylene production followed a similar trend under these conditions decreasing from 0.043 ± 0.005 to 0.034 ± 0.004 mmol/kg/h for uncoated and ACLS coated fruits, respectively, indicating an effect on ripening control. Additionally, ACLS and WCS coatings permitted the preservation of color without affecting anthocyanins content. However, the presence of anaerobic metabolites and reduction of terpenes production in cold stored coated raspberries indicated hypoxic conditions, which can adversely affect shelf‐life quality attributes of raspberries such as firmness and weight loss.     

Effect of three lipid/hydrocolloid coatings on shelf life stability of Golden Delicious apples

The shelf life quality of freshly harvested Golden Delicious apples coated with three individually developed lipid/hydrocolloid coatings was assessed throughout refrigerated storage. The apples were monitored for 8 weeks. The coatings resulted in low internal O₂ and the least loss of fruit firmness when compared with the non‐coated apple group. The coated apples had very little starch breakdown, minimum flesh colour development, or loss of titratable acidity content. Soluble solids and fresh weight loss remained unchanged for both the non‐coated and coated groups. Sensory analysis confirmed that the coated apples maintained consistent quality in firmness, crispness and juiciness throughout the storage period.     

Effect of Chitosan Coatings Enriched with Lauroyl Arginate Ethyl and Montmorillonite on Microbial Growth and Quality Maintenance of Minimally Processed Table Grapes (<Emphasis Type="Italic">Vitis vinifera</Emphasis> L. Kyoho) During Cold Storage

The effects of lauroyl arginate ethyl (LAE), chitosan (CTS), and CTS-containing montmorillonite and LAE coatings (CML) on the quality maintenance and shelf life of minimally processed grapes stored at 4 °C for 20 days were investigated. Compared with the control, LAE, and pure CTS coatings, the CML coatings effectively decreased grape weight loss, respiration, and decay incidence as well as microorganism counts of total aerobic bacteria, yeasts, molds, and lactic acid bacteria in grapes. The CML coatings also showed better effects on delaying the tissue softening and browning due to the decreased activities of polygalacturonase, pectin methyl esterase, and polyphenol oxidase. CML coatings did not significantly change the content of soluble solids and the titratable acidity or the pH value of grapes, compared with other samples. However, CML coatings ensured higher content of ascorbic acid and sensory quality in grapes. The results confirmed that CML coatings improve microbiological safety and preserve nutritional and sensory quality of minimally processed grapes.     

EFFECTS of SEMPERFRESH and JONFRESH FRUIT COATINGS ON POSTSTORAGE QUALITY of "SATSUMA" MANDARINS

Mandarins were coated with Semperfresh^TM and Jonfresh^TM edible coatings. the weight gain of mandarins after application of Jonfresh and Semperfresh coatings was 0.8% and 0.6% respectively. Weight loss, respiration rate, ascorbic acid, soluble solids (brix) and acidity changes of coated mandarins were compared with uncoated mandarins during storage at 20C and 40% RH for 4 weeks. Semperfresh^TM and Jonfresh^TM coatings delayed the ripening of mandarins. Both of the coatings were effective to reduce the change of ascorbic acid, soluble solids, titratable acidity and respiration rate. But Jonfresh^TM was determined to be most efficient coating for reduction of weight loss.     

Effect of Osmotic Dehydration and Pectin Edible Coatings on Quality and Shelf Life of Fresh-Cut Melon

The aim of this work was to investigate the influence of osmotic dehydration and pectin edible coating on quality parameters of fresh-cut melon. Fruits were osmodehydrated in 40°Bx sucrose solution containing 0.5% calcium lactate or dipped in 0.5% calcium lactate solutions. Then, samples were coated with 1% pectin. Melon pieces dipped in sanitizing solution (nontreated sample) were used as control. Weight loss, respiration rate, firmness, color parameters (lightness, chroma, and whiteness index), sensory acceptance, microbial growth, and structural changes of fruits were evaluated during storage at 5 °C for 14 days. The shelf life of the control sample was limited to 9 days due to microbial growth and sensory rejection, while treated samples showed a shelf life of 14 days. Higher preservation of firmness in coated samples was attributed to the action of calcium salt on melon structure, causing a strengthening of the cell wall. Calcium lactate also inhibited microbial growth along storage, improving microbiological stability of fresh-cut melon. The use of calcium lactate dips and pectin edible coatings hindered weight loss and maintained fruit color characteristics during the storage time. However, these pretreatments probably masked melon taste, reducing the sensory acceptance scores at the end of shelf life study. The combination of osmotic dehydration and pectin coatings was a good preservation alternative for fresh-cut melon, since it improved fruit sensory acceptance, promoting the reduction of product respiration rate, as well as the maintenance of quality parameters during 14 days.     

Quality and Shelf Life of Individually Shrink-Wrapped Peaches

Fresh redglobe peaches were defuzzed, treated with fungicide and shrink wrapped individually in polyolefin film. The wrapped and unwrapped fruits were stored at 1°C and 10°C, respectively, for periods up to 50 days. Samples of peaches were tested every week to examine the changes in quality as determined by visual observation, weight loss, titratable acidity, % soluble solids, texture and sensory profiles. Weight loss of fruits was reduced tremendously by shrink wrapping. The appearance, flavor and overall eating quality of the wrapped peaches were found to be better than the control fruits. The shelf life of wrapped peaches was 5–6 weeks at both 1°C and 10°C as opposed to 3–4 weeks at 1°C for the control peaches.     

3种处理方式对冬枣货架期品质的影响

以冬枣为试材,研究3种处理方式对其货架期品质的影响。通过测定冬枣的呼吸强度、硬度、总可溶性固形物、VC、乙烯释放量、乙醇积累等指标,研究热水浸泡、1-MCP熏蒸、纳米袋包装3种处理对冬枣果实的保鲜效果。结果表明:3种处理方法均不同程度保持了枣果货架期品质,其中纳米袋包装保鲜效果最佳,有效维持了冬枣果肉硬度和VC含量,延缓其色泽由绿到红的转变和总可溶性固形物上升,抑制了冬枣的呼吸强度及乙烯和乙醇的产生,货架期15d后,仍具有商品价值。     

Edible Coating Effects on Postharvest Quality of Green Bell Peppers

Green bell pepper fruits (Capsicum annuum L., cv. “Jupiter”) were coated with a mineral-oil-based coating or a cellulose-based coating. Three different milk-protein-based edible coatings (whey protein isolate, sodium caseinate, and sodium caseinate beeswax emulsion) plasticized with glycerol were also tested. The effects of these coatings were followed by measurement of changes in respiration, internal gases, color, firmness, and water loss during storage at 10°C, 80–85% RH for 20 days. None reduced respiration or affected color. Only the mineral-oil-based coating significantly reduced moisture loss, thus maintaining fruit firmness and thereby prolonging fruit freshness.     

银杏叶提取液复合涂膜对鲜切苹果品质的影响

以‘红富士’苹果为试材,采用0.5 mg/mL银杏叶提取液及其与1%海藻酸钠复合涂膜两种方式处理鲜切苹果,从色泽、硬度、质量损失率、VC含量、多酚氧化酶活性、菌落总数以及感官评定等方面对鲜切苹果的保鲜效果进行评价,探讨银杏叶提取液及其复合涂膜对鲜切‘红富士’苹果保鲜的影响。结果表明：银杏叶提取液处理和银杏叶提取液复合海藻酸钠涂膜处理均可降低鲜切‘红富士’苹果贮藏期间的呼吸强度及乙烯释放速率,延缓鲜切苹果可溶性固形物、可滴定酸和VC含量的下降,减缓鲜切苹果的质量损失及硬度的下降,抑制贮藏期间苹果表面微生物的生长,使多酚氧化酶和过氧化物酶的活性维持在较低的水平,较好地维持了鲜切苹果的感官品质,银杏叶提取液复合海藻酸钠涂膜保鲜效果最佳。     

CONTROLLED ATMOSPHERE STORAGE AND EDIBLE COATING EFFECTS ON STORAGE LIFE AND QUALITY OF TOMATOES

Tomatoes at pink stage maturities were coated with Semperfresh^TM edible fruit coating which is composed of sucrose esters of fatty acids, sodium carboxymethyl cellulose and mono-diglycerides of fatty acids. One group of coated and uncoated tomatoes were stored at 23 × 2C under air atmosphere, another group was stored at 12C under air atmosphere and third group was stored at 12C, 93–95% RH in a controlled atmosphere (CA) containing 3% CO₂, 3% O₂ and 94% N₂. Samples of tomatoes were analyzed for firmness, weight loss, titratable acidity, pH, soluble solids, sugars, ascorbic acid and lycopene to examine changes in quality during storage. Semperfresh^TM edible fruit coating was found to be significantly effective at both storage temperatures (23 × 2C and 12C) in air to delay changes in firmness, titratable acidity, pH, soluble solids, sugars, ascorbic acid and lycopene. Semperfresh^TM fruit coating reduced fruit weight loss as compared to fruit without coating but the difference between coated and uncoated tomatoes was not significant. Shelf-life of pink tomatoes was increased 3 days at 23 × 2C and 6 days at 12C in air by coating. CA storage delayed compositional changes in tomatoes significantly as compared to air storage of coated and uncoated tomatoes. CA storage also had a significant potential for reducing weight loss and microbial spoilage. Tomatoes were stored 40 days in CA. Coated and uncoated tomatoes exhibited the same results in CA.     

Fungal decay and shelf life of oranges coated with chitosan and bergamot, thyme, and tea tree essential oils

Chitosan coatings, containing or not essential oils (bergamot, thyme and tea tree oil), were applied to oranges (cv. Navel Powell). Antifungal effect was evaluated by applying coatings before and after inoculating the fruit with Penicillium italicum CECT 2294 (10(5) spores/mL), preventive and curative treatments, respectively. The effect of coatings on the quality parameters (acidity, pH, soluble solids, juice percentage, weight loss, firmness, color parameters, and respiration rate) was controlled for the different oranges samples throughout the cold storage time. Preventive antimicrobial treatments with coatings containing tea tree oil were the most effective with a reduction of the microbial growth (expressed as the percentage of infected samples) of 50%, as compared to the uncoated samples. The coatings did not lead to any relevant changes in the development of the sample quality parameters throughout the cold storage, except for a slightly reduced loss of both weight and firmness when the coatings contained bergamot oil. Practical Applications: Results of this study are a useful tool for the development of new environmental friendly and healthier commercial applications in the control of the main postharvest fungal decay of citrus fruits.     

Review: Effect of the combined application of edible coatings and osmotic dehydration on the performance of the process and the quality of pear cubes

The objective of the present work was to evaluate the combined effect of the application of edible coatings (sodium alginate and low methoxyl pectin) and different osmotic dehydration conditions (sucrose solution: 40 and 60 °Brix, temperatures: 20 and 40°C and times: 1, 2, 4, 8 and 16 h) on pear cubes (water loss, solid gain, performance ratio, the total colour differences, mechanical properties, phenolic content and sensory analysis). The results indicated that samples coated with low methoxyl pectin and treated under 60 °Brix for 16 h at both temperatures (20 and 40°C) presented the best process performance. Statistical analysis showed that the application of the coatings resulted in greater firmness and stiffness of the pear cubes at the end of osmotic dehydration. Besides, alginate coating best preserved the phenolic content (31.4%) than uncoated (26.04%) and pectin-coated (20.77%) ones. However, total colour differences were not improved with the use of edible coatings (alginate or pectin). In terms of quality, the samples coated with both hydrogels had good overall acceptability by the evaluators and good mechanical properties. However, further studies are required to decrease the difference in colour and leaching of bioactive compounds in pear cubes due to the osmotic dehydration treatment.     

Effect of cut‐type on quality of minimally processed papaya

BACKGROUND: This research was undertaken to study the effects of different cut‐types (cube, parallelepiped, cylinder and sphere) on the quality and shelf‐life of papaya cv. Sunrise Solo. Physicochemical analyses were carried out during 10 days of storage at 4 °C to determine colour, firmness, pH, titratable acidity, total soluble solids, weight loss and vitamin C content. Microbiological analysis and sensory evaluation were also performed. RESULTS: Papaya spheres (1.55 cm radius) presented the most favourable physicochemical and microbiological properties (smaller changes in colour parameters L*, a*, b*, chroma and hue angle, firmer texture, lower increase in pH, higher titratable acidity, almost constant total soluble solids, reduced weight loss, high vitamin C content and lower microbial loads) and sensory characteristics on day 10, while papaya cubes (1.4 cm side) proved to be the least acceptable. CONCLUSION: The results of physicochemical, microbiological and sensory analyses performed on different cut‐types of papaya indicated acceptable fresh‐cut produce during 10 days of storage at 4 °C. The potential shelf‐life at 4 °C is therefore 10 days, provided that no contamination occurs in the postharvest period and during minimal processing operations. Copyright © 2008 Society of Chemical Industry     

Preservation of quinces by the combination of an edible coating material, Semperfresh, ascorbic acid and cold storage

Quinces (Cydonia oblonga, Miller) have a crucial economic value owing to their demand as jams or compote, and their high vitamin and fiber content. A preservation method for extending the shelf life of quinces by the combination of an edible coating material, Semperfresh, ascorbic acid and cold storage was designed in this study. The ascorbic acid content, firmness, total sugar, pH, titratable acidity, respiration rate, soluble solids, weight, total humidity, mold, yeast, and total mesophilic aerobic bacteria count were monitored. It was found that the triple combination of Semperfresh, ascorbic acid and cold storage provides high microbial, chemical and sensorial qualities for the quinces, leading to an extension in shelf life when compared with untreated quinces.     

淀粉-壳聚糖可食性复合薄膜保鲜布林的研究

本文主要研究了不同种类的淀粉与壳聚糖复合所形成的被膜对于布林的保鲜效果。分别用木薯淀粉,土豆淀粉,玉米淀粉与壳聚糖制成不同涂膜液对布林进行涂膜处理,在常温(15～25℃)下储藏。涂膜的布林在贮藏期间,其水分损失,硬度,可溶性固形物,总酸度的变化均小于对照组, 并且可延长保质期3～7d。就不同的淀粉成分而言,对于布林的保鲜作用,土豆淀粉-壳聚糖复合薄膜的保鲜作用最佳,玉米淀粉-壳聚糖复合薄膜的作用优于木薯淀粉-壳聚糖复合薄膜。     

石榴-胡萝卜复合饮料理化性质、抗氧化活性及其货架期的研究

以石榴、胡萝卜为原料,按质量比1∶3、1∶1、3∶1混合配制石榴-胡萝卜汁复合饮料,研究常温(25±1)℃下60 d的储存期内其物理化学性质(pH值、可溶性固形物、总酸度)、抗坏血酸、总酚以及抗氧化活性的变化,并对复合汁进行感官评价。结果表明,3个样品的pH值分别为4.04、3.92和3.38,可溶性固形物分别为5.02%、6.14%和8.13%,总酸度分别为0.74、0.74 g/100 mL和0.77 g/100 mL,在60 d的货架期pH值有所降低,可溶固形物含量没有明显的变化,而总酸度有所增加。抗坏血酸含量以质量比为1∶3的混合汁占优,总酚含量、DPPH自由基清除率以质量比为3∶1的混合汁占优,3项指标在货架周期内呈总体下降趋势。质量比为1∶1的石榴-胡萝卜复合汁感官评价得分最高。     

Effect of 1-Methylcyclopropene on the Quality of Fresh-cut Apple Slices

ABSTRACT: The objective of this project was to treat fresh-cut apple slices with the ethylene inhibitor 1-methylcyclopropene (1-MCP) to retard ethylene-induced deterioration and senescence and to prolong the shelf life of such products. Intact Braeburn and Pacific Rose apples were treated at different times with 1-MCP, cut, and stored at 0 °C. Samples were analyzed initially and then weekly for ethylene, respiration, flesh firmness, tissue color, titratable acidity, and soluble solids content during 5 wk of storage. 1-MCP treatment was effective in reducing ethylene production, respiration, and loss of firmness and color of slices when applied to whole apples directly after harvest. Total sugar and acidity levels were not affected significantly.     

Combined effects of postharvest heat treatment and chitosan coating on quality of fresh‐cut mangoes (Mangifera indica L.)

The influence of heat treatment combined with coating on sensory quality, physico‐chemicals characteristics (firmness, colour, pH, titratable acidity, total soluble solids and total carotenoids content) and microbiological quality of fresh‐cut mangoes were studied. Whole mangoes (Mangifera indica cv ‘Tommy Atkins’) were subjected to hot water dipping (HWD) at 50 °C for 30 min and cooled for 15 min. Heated and unheated fruits were minimally processed and mango cubes were coated with chitosan solution (0.25% w/v) dissolved in 0.5% (w/v) citric acid, and stored for 9 days at 6 °C under ambient atmosphere. This study showed that both HWD 50 °C for 30 min and chitosan coating, either alone or combined, did not affect the taste and the flavour of mangoes slices. The chitosan coating combined with HWD or not inhibited the microbial growth for 9 days at 6 °C. Indeed chitosan coating was used for his antimicrobial proprieties. HWD 50 °C for 30 min was the beneficial treatment to maintain firmness and colour during 9 days at 6 °C.