فهرست مطالب سارا عشقی

Blood orange has high nutritional value due to high concentrations of vitamin C، fiber، folate، minerals and phytochemical compounds، such as flavonoids، amino acids، triterpenes، phenolic acids and carotenoids. The blood oranges contain greater amounts of antioxidants than other oranges. Orange fruit continue to respire، after harvest so there are probability changes of bioactive compounds that present in this fruit. The aim of this study was to investigatethe changes of the bioactive compounds، antioxidant activity and their relationship with respiration rate of blood orange during storage. Blood oranges var. sangria was purchased from the Citrus Research Institute of Iran. The fruits were transported to the laboratory immediately after harvesting and were stored at 5-4°C and 85-90% relative humidity for 50 days. Changes of concentration of vitamin C، flavonoid compounds، total carotenoids، antioxidant activity and respiration rate were evaluated once a week during storage. The concentration of vitamin C decreased، but the concentration of flavonoid، total carotenoids، antioxidant activity and respiration rate of blood orange increased during storage. The concentration of vitamin C، flavonoid، total carotenoid، antioxidant activity and respiration rate of blood orange changed during storage. With attendance to nutritional value and the functional compounds of orange fruit، use of appropriate actions are recommended to better maintenance of the bioactive compounds and antioxidant activity. Also، considering effects of respiration rate on the bioactive compounds and antioxidant activity، decrease of respiration rate of blood orange during storage could lead to be better preservation of the functional compounds.

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. 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%). 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. 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.