Effects of Edible Coating Materials and Stages of Maturity at Harvest on Postharvest shelf life and Physicochemical Properties of Tomato (Lycopersiconesculentum Mill.)Fruits.

Abstract

Tomato (Lycopersicon esculentum Mill.) is among the most perishable horticultural products and, after harvest management of this crop is a crucial task to minimize losses and extend their shelf life. This work was conducted to determine effect of edible coating material, coated at different harvesting stage of tomato fruits to prolong their storage life with desired physicochemical properties. Fruits of a fresh tomato variety Barbados were obtained from Awassa Jittu farm, Ethiopia. Fruits were harvested at mature-green, turning and light red stages. Treatments from three maturity stages were coated with two types of edible coating materials (Pectin and Chitosan) and laid out in factorial arrangement. of completely randomized design with three replications. Sample fruits were evaluated periodically for different changing parameters with storage time, including weight loss, color, firmness, pH, total soluble solids (TSS), titratable acidity (TA), TSS to TA ratio, ascorbic acid, total phenolic content, lycopene and extent of disease incidence and severity. Results of the study indicated that, coating of tomato fruits either with chitosan or pectin was found to delay the ripening process and maintain fruit quality. All combined treatment combinations resulted in a significant delay in the change of weight loss, TA, TSS, disease incidence, disease severity and ripening index as compared to that of uncoated control fruits. Accordingly the shelf life was extended during ambient storage at average temperature 220 C+1 and 74+1 % relative humidity. Maximum shelf life was observed for tomatoes harvested at turning stage coated by pectin (17days) followed by chitosan coated fruit at harvested at turning stage (16 days). Minimum shelf life was for uncoated fruits at the same harvesting stage (10 days). Moreover, in respect of antioxidant properties of certain compounds, coated tomato fruits revealed higher amount of ascorbic acid, lycopene and phenolic contents. Fruits coated with either chitosan or pectin at turning maturity stage showed the best result in almost all quality parameters. Thus, it can be concluded that choosing the optimum stage of maturity of fruits plays a key role in order to achieve the full objectives of coating as it has a great influence on the quality attributes of tomato fruits. The shelf life of uncoated fruits was on average around 10 days as opposed coated fruits stayed sound for about 17 days. This provides an advantage of prolonging the shelf life of tomato fruit by one week with sole application of edible coating materials. The result can be very promising, if coating materials combined with low temperature storage.