The Effect of Edible Coatings on the Quality and Storage Life of Cherry cv. Lambert

IntroductionCherry, with the scientific name Prunus avium L., is one of the most important stone fruit trees in temperate regions, belonging to the Rosaceae family and the Prunoideae subfamily. Edible coatings are thin layers of materials that are used on the surface of the product and are an alternative to protective wax coatings. Chitosan is a coating that has a polysaccharide structure and is composed of glucosamine and N-acetylglucosamine units and is obtained from the shell of crustaceans such as crabs and shrimps. Clear, odorless, non-sticky gel with high and firm absorption power is extracted from the inner parts of aloe vera plant leaves. Between this gel and the outer skin of the leaf, there are special cells that contain a yellow liquid and when this liquid dries, aloe vera juice is produced. This gel is completely healthy and compatible with the environment, and its pH is about 4.5, which can replace various fruit coatings in the post-harvest stage. The purpose of this research was to investigate the combined effect of aloe vera gel and chitosan in maintaining the quality characteristics post harvesting and increasing the shelf life of Lombard cherry fruit. Materials and MethodsLambert black cherry fruit was obtained from the garden complex of Moghan Agriculture and Animal Husbandry Company located in Pars Abad city of Ardabil province. they were immediately transferred to the Postharvest Physiology Laboratory, Department of Horticultural Sciences, Faculty of Agriculture and Natural Resources, Mohaghegh Ardabili University, for the desired treatments.This study aimed to extend the shelf life of cherry fruit with two edible chitosan coatings (0, 0.5, 1, 1.5% w/w) and aloe vera gel (0, 15%, 30%, 45% w/w) was performed as factorial in a completely randomized design in three replications. The measured parameters were soluble solids, vitamin C, total acidity, anthocyanin, starch, weight loss and firmness of fruit tissue that were evaluated at harvest time and 45 days after harvest. Results and DiscussionThe results of analysis variance showed that the effect of time had significant on cherry fruit flavor (P<0.01). The use of Aloe vera gel had a significant effect (P<0.01) on soluble solids, starch, firmness, fruit flavor and also weight loss (P<0.05). The effect of chitosan treatment also were significant on total soluble solids, starch, firmness, and fruit flavor (P<0.01). Moreover, Interaction effect of aloe vera gel and chitosan treatments on total soluble solids, starch, firmness, and fruit flavor were significant (P<0.01) during at storage time. The compare means showed that the ratio of soluble sugars to total acid was increased. The highest soluble solids and their ratio to total acid were obtained as a result of the using of 45% aloe vera gel with 0.5% chitosan coating. Combining of aloe vera gel with 30% and 45% concentrations with chitosan at 1% and 1.5% were able to maintain better firmness of fruit tissue compared to other treatments during storage time.The highest residual starch in the fruit was obtained in using aloe vera gel treatments at concentrations of 15%, 40% and 45% with 1% chitosan during storage. Also, the use of aloe vera gel (all three levels) was exceled compared to control on fruit weight loss. By reducing the activity of ethylene, chitosan causes a delay in ripening and aging and as a result reduces the firmness of the fruit. Aloe vera gel reduces the activity of pectin methylesterase, poly-galactronase and beta-galactosidase. These enzymes destroy the cell wall and soften the fruit. ConclusionThe interest in using edible coatings to maintain the optimum quality of fruits during the marketing and storage process has increased. Edible coatings can act as a barrier, thereby reducing quality loss, inhibiting gas exchange, controlling respiration rates, and preventing the growth of microorganisms that cause fruit decay. The results clearly indicated the preservation of the quality of cherry fruit with the use of edible coatings compared to the control. The use of the treatment combination of chitosan at a concentration of 1.5% with aloe vera at a concentration of 45% has had a positive and significant effect to maintain the quality of cherry fruit after harvesting. Therefore, the use of this treatment combination is recommended to increase the storage life and maintain the quality of Lambert cherry fruit during the storage period.