Food Technology
Hoda Ghorbanzadeh; Jafar Milani; Ali Motamedzadegan
Abstract
IntroductionWith the growth of the population and more demand for obtaining food and supplying the required food, the interest in the cultivation and consumption of edible mushrooms has increased. Since 1990, the world has focused on the mushroom production industry. In recent years, mushrooms have become ...
Read More
IntroductionWith the growth of the population and more demand for obtaining food and supplying the required food, the interest in the cultivation and consumption of edible mushrooms has increased. Since 1990, the world has focused on the mushroom production industry. In recent years, mushrooms have become one of the most important food and medicinal sources. One of the largest species of edible mushroom is button mushroom (Agaricus bisporus), which has high nutritional and medicinal value. Button mushroom has high nutritional value due to the presence of things such as fiber, carbohydrates, protein, amino acids, minerals, vitamins, etc., and it also has antioxidant, anti-cancer, and anti-diabetic properties. This food has shown good health properties for humans. The quality of button mushrooms is determined by their color, texture, and taste. Color is the first characteristic that is perceived by consumers. Browning is one of the main reasons for the loss of mushroom quality, which reduces the commercial value of mushrooms. One of the most used methods today is the use of edible coatings for perishable foods, these coatings almost prevent the penetration of oxygen, depending on the type of coating used, and reduce the loss of moisture during storage. Chitosan has functional characteristics such as antimicrobial and antioxidant properties, and as an edible film, it can be considered a very good carrier to be combined with antioxidant and antimicrobial agents.Materials and methodsTo make chitosan solutions, first, each type of chitosan (70% deacetylated, 80% deacetylated, 90% deacetylated, and 100% deacetylated) was weighed in amounts of 0.5g, 1g, and 2g. then it was dissolved in 100 ml of 0.5% acetic acid solution and stirred for 12 hours at a speed of 1000 rpm at room temperature to dissolve uniformly. After 12 hours, each sample It was centrifuged for 15 minutes at 6000 rpm at 25 °C to separate the undissolved material. Mushrooms were prepared freshly harvested, washed with water, and then excess moisture was removed. After sorting and screening in terms of size and approximate weight, the mushrooms were added to 0.5%, 1%, and 2% chitosan solutions without being sliced and were immersed in the solution for one minute. The control sample was immersed in 0.5% acetic acid solution for one minute. After that, the mushrooms were air-dried at room temperature for one hour, and at the end, their excess moisture was removed with a tissue. The mushrooms were placed in 18*14 size polyethylene zip-top bags and stored in a refrigerator at 4°C. The effects of chitosan coating on weight loss, mushroom color and browning index, enzyme activity, texture, and total phenolic compounds were studied.Results and discussionThe results indicated that in maintaining the amount of total phenol, controlling the peroxidase enzyme activity, the degree of firmness of the mushroom during storage and the amount of gumminess, the best treatment was chitosan with a deacetylation degree of 70%, while in controlling the weight loss, the activity of poly Phenol oxidase and sensory test, chitosan treatment with 100% and 90% deacetylation degree had better results, and in terms of browning index and texture, chitosan treatment with 80% deacetylation degree showed better performance. This study showed that the use of chitosan coating can be effective in maintaining the characteristics of edible mushrooms.ConclusionsThe spoilage of edible mushrooms happens in a short time, and the storage of mushrooms has become one of the most important things in mushroom production. Coating edible mushrooms is one of the suitable methods to increase the shelf life of edible mushrooms. In this research, chitosan with four degrees of deacetylation and three different concentrations was used as a coating for edible mushrooms. The results indicated that coating the mushroom with chitosan could delay the occurrence of spoilage and change its color or texture.
Mozhgan Karimi; Ainaz Khodanazary; Seyed Mehdi Hosseini
Abstract
Introduction: The Spangled emperor (Lethrinus nebulosus) is one of the valued fish species in Persian Gulf, which due to its high nutritional quality and excellent sensory properties, is preferred by the customers in the south of Iran. Because this species is consumed domestically, it is very important ...
Read More
Introduction: The Spangled emperor (Lethrinus nebulosus) is one of the valued fish species in Persian Gulf, which due to its high nutritional quality and excellent sensory properties, is preferred by the customers in the south of Iran. Because this species is consumed domestically, it is very important to extend its shelf life, which is normally quite limited when kept refrigerated. Vacuum packaging (VP) is one of the methods of the natural preservation in order to delay the degradation and maintain the quality of the products longer. VP is widely used as a supplement to ice or refrigeration to decrease the supply of oxygen to the aerobic bacteria in the flesh to extend the shelf life of product. Chitosan have been used in seafood products to inhibit the growth of bacteria in stored fish in refrigerator and retarded the oxidation of unsaturated fatty acids in fish muscle before vacuum packaging. Chitosan, a linear polysaccharide of randomly distributed β-(1-4)-linked D-glucosamine and N-acetyl-D-glucosamine, is a biocompatible polysaccharide obtained from deacetylation of chitin. Edible coating is a thin layer of edible material formed as a coating on a food, while an edible film is a preformed thin layer which once formed can be placed on or between food components. In food industry, chitosan coatings have been used successfully because of some advantages such as edibility, biodegradability, aesthetic appearance and barrier properties, being nontoxic and non-polluting, as well as carrier of foods additives (i.e.: antioxidants, antimicrobials). Therefore, these coatings can retain quality of raw, frozen and processed foods including fish items by preventing bacterial growth and delaying lipid oxidation. Materials and methods: Lethrinus nebulosus with an average weight of 500 g was caught with gill net in the Persian Gulf, Khorramshahr, Iran in July 2016. Fish samples were placed in crushed ice with a fish/ ice ratio 1:3 (w/w) and transported to the fish processing laboratory with 2-3 h after catch. They were washed with tap water and two fillets were obtained from each fish after removing the head and gutted. Chitosan solution was prepared with 1% (w/v) chitosan (Sigma Chemical Co., medium molecular weight, viscosity 200-800 cP) in 1% v/v acetic acid. To achieve complete dispersion of chitosan, the solution was stirred at room temperature to dissolve completely. Glycerol was added at 0.75 ml/g concentration as a plasticizer and stirred for 10 min. All films were obtained by casting 100 ml film forming solution on a nonstick surface (16*27cm), dried at ambient temperature (20˚C) until a firm surface but still with adhesive properties was obtained. After evaporation the films were peeled off from the plates. Fillet samples were randomly assigned into four treatment lots consisting of: one control lot (un-coated), second lots packaged with VP, third lots wrapped with films prior to VP, fourth lots immersed for 30 s in chitosan solution. Then the fish fillets were removed and allowed to drain for 2 h at ambient temperature (20˚C) in order to form the edible coating. All samples were stored at 4±1˚C for 12 days. Chemical, microbiological and sensorial analyses were performed at 3-day intervals to determine the overall quality of fish. Results and discussion: Combination of vacuum packaging and chitosan treated samples effectively retarded the TVB-N and TMA values and inhibited the growth of total viable count and psychrophilic count bacteria during refrigerated storage. Therefore, to extend the shelf life and delay the deterioration of fresh Spangled emperor fillets during refrigerated storage, chitosan coating prior to vacuum packaging is more appropriate. These coatings and films also showed antioxidant effects, since TBA and FFA values was lower than control samples at the end of the storage. There was no significant difference between coating and film in reducing TBA of fillets and bacterial contamination. Therefore, chitosan coating and film prior to vacuum packaging provides a type of active packaging that can be utilized as a safe preservative for fish under refrigerated storage.
Reza Farahmandfar; Maryam Asnaashari; Milad Amraie; Mohammad Salehi
Abstract
The consumer’s acceptance significantly reduces during the storage of fresh cut fruits. Edible coating is one of the most innovative ways to maintain quality and improve shelf life of fresh fruits and vegetables. The objective of this study was to assess the suitability of quince seed gum (QSG) ...
Read More
The consumer’s acceptance significantly reduces during the storage of fresh cut fruits. Edible coating is one of the most innovative ways to maintain quality and improve shelf life of fresh fruits and vegetables. The objective of this study was to assess the suitability of quince seed gum (QSG) at different concentrations (0.5, 1 and 1.5%) as edible coatings for banana slices and to determine their influence on changes in physicochemical properties during storage at 4 °C and 40 °C. Data on shrinkage, weight loss and color were collected and subjected to statistical analysis. Banana slices which coated with 1 % of QSG and stored at 4 °C showed significantly better physicochemical characteristics. Higher temperatures result in more rapid changes of quality parameters. On the other hand, samples coated with gum reduced the weight loss and shrinkage during storage. It is recommended that 1% quince seed gum can be used to reduce the surface fresh-cut banana browning.
Zahra Shabanian; Javad Fattahi Moghadam; Seyed Abolhasan Alavi
Abstract
Introduction: Thomson orange is an important citrus verity which cultivated and produced widely in the north and south of Iran. The extra part of this production is stored in the common storage for several monthsespecially in the north area. The role of storage and fruit coating are important due to ...
Read More
Introduction: Thomson orange is an important citrus verity which cultivated and produced widely in the north and south of Iran. The extra part of this production is stored in the common storage for several monthsespecially in the north area. The role of storage and fruit coating are important due to maintain the nutritional value and enhancing the ‘Thomson’ orange storage life. The aim of this study was to investigate the possibility of maintainingthe fruit quality using coatingtreatmentsin common storage.Materials and methods: In this experiment the harvested fruits were divided in to seven groups randomly, then thefruits of each group were treated using different coating (Polyethylene wax, Shine wax, Storage-wax, Britex Ti wax, Freezer bag, Fungicide ‘Tecto 60’) and Control group without any coating. All the groups were stored in the common storage (5-12 oC and 75-85% RH) for tree month. Some physicochemical and sensory characteristics were investigated including percentage of juice, weightless, losses rate, total soluble solid (TSS), titratable acidity (TA), TSS/TA, peel and pulp total phenolics, ascorbic acid, antioxidant activity in peel and pulp, color indices (L*, chroma and hue angle), peel and pulpAppearance, aroma, flavor, sweetness, sourness, off-flavor, bitterness, acceptance of the fruit each 30 days intervals during storageResults and discussion: Results showed that, the juice percentage declined with decreasing of weight loss in all treatments, but the fruits which treated by freezer bag had the highest juice percentage (38.4%) and the lowest weight loss (1.04 g). Weight loss in Citrus fruit depended on the length and storagetemperature during storage and usually increased on low moisture conditions.Therefore, fruits which packed by polyethylene bags were resistance to water loss through surface peel as well as during storage. The losses increased during the early month of storage especially in freezer bags and shine wax treatments by 4.67 and 3.33% respectively. It seems that bags inner spaceis suitableatmosphere for growing of peniciilium fungi. Color indices (L*, c, h) were in optimum range in all treatments during storage. The length of storage had no significant effect on total soluble solid but affected significantly using coating treatments than control. Moreover, the titratable acidity gradually declined during storage but wax coating maintained TA value higher than other treatments significantly. Overall, the TSS/TA level was increased during storage and the highest ratio (16.14) was observed in control. The increase in TSS/TA was due todecreasing of acidityandincreasing of polysaccharidesduring storage. The total phenolics content decreased in all treatment in peel and pulp as the highest phenolics content with 0.71 mg.g-1 occurred in freezer bag treatment. The amount of ascorbic acid were increased with 42.33 mg.100gr-1 in fruits which treated by Britex Ti wax than control at the end of storage. It seems that lower observation ofascorbic acid in coating treatment due to reduction of the oxygen molecules in fruit tissue by coating. Antioxidant capacity was increased in both peel and pulp of fruits, except in the freezer bag and control treatments. The freezer bag treatment had highest sweetness 7.22 and lowest sourness 1.79 compared to the other treatments and the control. The Britex Ti treatment had the highest level of off-flavor (2.15) and bitterness (1.56) compared to the other treatments and the control. The freezer bag treatment had the highest score (8.09) in the acceptance of the fruit, compared to the other treatments.Conclusion: According to physiochemical and sensory evaluation, Britex Ti, storage-waxes and freezer bag treatments had positive influences on fruit quality in common storage.Thereforethe Storage-wax which produced by the internal companies,it is preferable to be use by citrus growers to maintaining the fruits quality in the common storage.
