جستجوی مقالات مرتبط با کلیدواژه "توت فرنگی" در نشریات گروه "فنی و مهندسی"

Every year, a large part of the Produced strawberries is losses due to postharvest corruption. On the other hand, the demand for Biodegradable packaging materials has increased sharply due to environmental concerns about the use of petroleum polymers. Therefore, biopolymer-based packaging materials have a high potential for replacement with petroleum plastics. Research has also shown that plant essential oils can control postharvest diseases of agricultural products. However, their use is associated with difficulties due to physical and chemical instabilities odors and taste in the product. One of the best way to solve this problems is to include essential oils in the packaging film. Therefore, the present study aimed to investigate the effect of biodegradable film based on Zein containing Zataria multiflora essential oil (with concentrations of 0, 5, 10 and 20% w/w) as an active packaging to increase the Postharvest shelf life of strawberry fruit. The effect of films on maintaining the quality properties of strawberries during 15 days of storage at 4°C was evaluated and the amount of changes in weight, firmness, soluble solids, pH, treatable acidity, vitamin C and microbial contamination of strawberry samples during this period were evaluated. The results showed that during the storage, the quality of the samples decreased but the decreasing trend in packaged samples was much less than unpackaged samples. Also, the addition of essential oil to the polymer film improved the quality properties of strawberries, and with increasing the concentration of essential oil, the quality of strawberry samples decreased. Therefore, it seems that it is possible to greatly reduce the waste after harvest of strawberries by using the biodegradable film of saddle containing Zataria multiflora essential oil as an active packaging.

The aim of this study is to increase the shelf life and quality of strawberries, using a composite coating of concentrated milk protein-pectin reinforced with calcium chloride and Nigella sativa L. essential oil during 10 days of storage at 4±1°C. The effect of edible coating based on condensed milk protein (4, 6 and 8%), pectin (0, 2 and 4%), calcium chloride (1, 2 and 3%), glycerol (2, 3 and 4%) and Nigella sativa L. essential oil (2%) is investigated. After optimizing the microbial quality of coated strawberries, their physicochemical properties, antioxidant activity, anthocyanin content, and tissue hardness were compared with the control samples at 5 and 10 days after storage. All the studied qualitative characteristics of the coated samples were significantly different from the control samples (p <0.05). The results showed that this edible coating maintains the quality of strawberries in comparison to the uncoated control samples due to rot reduction.

Low storage time and high spoilage rate of some fruits, such as strawberries, can cause many economic losses to countries every year. Therefore, the application of new methods such as edible coatings can be effective in resolving this problem. In this study, the effects of calcium alginate coating contain native probiotic bacterium L. plantarum KMC45 and bacterial suspension in distilled water on the qualitative characteristics of produced probiotic strawberry during two weeks storage in refrigerated were investigated. The results showed that the application of calcium alginate containing probiotic bacteria was more effective in preserving the strawberry quality characteristics than the treatment of immersion in the probiotic bacterial suspension. This treatment compared to control treatment decreased the weight loss, texture softening as well as the decay percentage of strawberries during the 14-days by 2.38, 1.31 and 40%, respectively. Also in this study, changes in color indexes such as L *, Hugh angle and chromium in the coated samples were less than the control treatment. In addition, the results of total viable count of L. plantarum KMC45 in different strawberry treatments during storage at 4 ° C showed that after two weeks, the decline of population in bacterial suspension coating treatment was 2.97 log, while in the calcium alginate coating treatment was only 0.95 log. The calcium alginate coating was not affected on the taste and odor of strawberry, but it increased the score of other sensory characteristics such as texture, appearance, and overall acceptance compared to the other two treatments. Therefore, calcium alginate coating is recommended as a suitable carrier for the transfer of probiotic microorganisms to fresh strawberry, which can increase the shelf life of them and promote the production and development of new probiotic products.

Strawberry is one of the most popular fruits among consumers. However, the shelf life of strawberry is moderately low and freezing can be applied as a suitable method with little effects on the antioxidant properties of strawberries. However, the effect of freezing on sensory characteristics requires further investigations. On the other hand, analysis of vague and non-parametric results of sensory evaluation using mathematical methods such as fuzzy logic has been noticed. In the present study, strawberry fruits were stored in the freezer at -18±2° C for six months and the effect of freezing on the strawberry juice was evaluated. Frozen strawberries were brought out at Day 0, 3, 30, 60 and 180 and after preparing juice, were evaluated for sensory characteristics using five-point hedonic method and data were analyzed using fuzzy logic. Sensory attributes were color, aroma, taste and mouthfeel sensation. In this study, physicochemical properties such as pH, acidity, total phenol content and antioxidant activity were measured. Sensory evaluation of strawberry specimens showed that freezing did not considerable effect on overall acceptance even despite changes in pH and acidity. Due to freezing, the samples had a decrease in pH (1.92%) and an increase in acidity (0.18%) as well as a decrease in antioxidant activity (25.26%) and phenolic compounds (0.022%). The results of physicochemical and antioxidant activities, total phenol compounds and sensory evaluation by fuzzy logic generally create the view that freezing is a suitable method for long storage of strawberry fruit.

In this research, edible film made of carboxymethyl cellulose with different percentages (0.0, 0.2, 0.4, 0.6%) of sesame oil was prepared and its physical and mechanical properties were investigated. Edible coating was prepared from the treatment with optimum percentage and its microbial properties were measured. The data were analyzed by factorial test in a completely randomized design. Analysis of variance was performed using SPSS software and mean comparisons were performed by Duncan's multiple range test. Based on the results, the mechanical and physical factors showed that the tensile strength, elastic modulus in the coating containing 0.2% oil were lower than the control treatment and the Strain at break point increased. Oil concentration did not show a significant difference (P> 0.05) in water vapor permeability of emulsion films.Antimicrobialedible coatings containing 0.2% sesame oil solution with potassium sorbate composition had good inhibitory effect on fresh strawberry fruit.