Effect of UV-C Hormesis in Regulating Anthracnose Disease and Postharvest Quality of Tomato

Abstract

Purpose : Anthracnose disease caused by Colletotrichum coccodes is a significant postharvest disease in tomatoes. Although there are negative impacts of fungicides usage on fresh produce, at present, it is the most common method of eliminating diseases. UV-C hormesis was used in this study as a trending non-chemical postharvest treatment. Research Method : Tomato varieties 'Thilina' and 'Roma' were used to check the efficacy of UV-C treatments. Five different UV-C dosages (0, 1, 2, 3, 4, 5 kJ/m 2) were applied to pure cultures of C. coccodes (254 nm at a distance of 15 cm). The selected dosages (3.0 and 4.0 kJ/m 2) were tested on the effect of anthracnose disease development in vivo and the change in postharvest quality parameters (weight loss, firmness, shelf life, antioxidant and total phenolic content). Antifungal activity of the peel was investigated using Cladosporium bioassay. Findings : Weight loss of treated 'Thilina' variety has significantly increased (P < 0.05). The antioxidant activity and the total phenolic content of both treated varieties have increased. The firmness has significantly retained in treated 'Thilina' variety. Further, the shelf life has significantly extended in both treated varieties by approx. 2 folds compared to the non-treated control. All tested tomato samples indicated the presence of antifungal compounds in their peels. Therefore, to suppress anthracnose disease 4.0 kJ/m 2 , and 3.0 and 4.0 kJ/m 2 are the most suitable UV-C dosage for 'Thilina' and 'Roma' respectively.