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Background and Objective: Thomson navel orange has a high nutritional value due to the high concentration of vitamin C, fiber, folate, minerals, and phytochemical compounds such as flavonoids, amino acids, triterpenes, phenolic acids and carotenoids. The postharvest respiration of orange fruit may produce changes in its bioactive compounds. The objective of this study was to investigate changes in the bioactive compounds, including ascorbic acid, flavonoids, and total carotenoid concentrations, as well as antioxidant activity and respiration rate of Thomson navel oranges, during storage. Materials and Methods: Thomson oranges (citrus sinensis) var. navel were purchased from Iran Citrus Research Center (Ramsar) and transported to the laboratory immediately after harvest and kept in cold store at 4-5 °C and 85-90 % relative humidity for 65 days. Changes in the concentrations of vitamin C, flavonoid compounds and total carotenoids, as well as in the antioxidant capacity and respiration rate of the oranges, were measured at 7-day intervals. Results: Analysis of the data obtained showed that after 56 days of storage the concentrations of total flavonoides and total carotenoids, as well as the antioxidant activity and respiration rate of the oranges, increased by 36 %, 39 %, 19.6% and 94%, respectively, while the concentration of ascorbic acid decreased by 60.5% (p≤0.05). Effects of storage on the bioactive compounds concentrations, antioxidant activity, and respiration rate were significant )0.05). Changes in the concentrations of compounds with an antioxidant activity and the respiration rate affected the antioxidant activity of oranges during storage. Conclusion: Based on our results, and considering the nutritional value and functional compounds of orange fruit, using suitable technology to better protect the bioactive compounds and antioxidant activity of this valuable fruit is recommended. Keywords: Thomson orange, Bioactive compounds, Respiration rate, Antioxidant activity, Storage

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Background and objective: Strawberries are highly sensitive to fungal agents and, as a result, have a short shelf life. Using chemical fungicides to extend shelf life is a great health concern. Therefore, developing safe methods to control perish ability and maintain quality of strawberries during storage is crucial. Considering the successful application of chitosan in edible coating formulae and its proven antifungal properties due to its nano-particles prompted us to initiate this study aiming at assessing the efficiency of an edible coating based on chitosan nano-emulsion in delaying perish ability, maintaining quality and increasing the shelf life of strawberries. Materials and methods: After picking, strawberries were coated with nano-emulsion with particle sizes of 50-100±10 nanometers and containing 0.5% chitosan as an antimicrobial substance and stored, along with control samples, at a temperature of 4±1℃ and a relative humidity of 70%. At 4-day intervals qualitative indicators, including acidity, soluble solids, texture firmness, weight loss, respiration rate, antioxidant activity, anthocyanin concentration, ascorbic acid and percentage of damage, were determined in three replicates (confidence interval = 95%). Results: Coating strawberries with a nano-emulsion containing 0.5% chitosan had, in addition to delaying the fruit damage, positive effects on their quality parameters. As compared to uncoated samples, the treated samples were firmner and their weight loss, respiration rate and percent damage were lower. Also,anthocyaninsvandvascorbic acid were better preserved in the coated strawberries than in the control cuncoated sample. Changes in acidity and soluble solids were not considerable. Conclusion: Coating strawberries with a nano-emulsion containing chitosan can be introduced as a safe and effective method to increase their shelf life from 8 days to 20 days (2.5 times as long) and better preserve their quality. Keywords: Nano-emulsion containing chitosan, Strawberry, Shelf-life