Effects of Chitosan Coating on the Postharvest Quality and Antioxidant Properties of Sweet Pepper (Capsicum annuum L.)

Abstract

The development of diseases and decay in vegetables after harvest limits their shelf life and saleability. However, there is an increasing concern with the use of synthetic chemicals as postharvest treatments. Hence, there is a need to develop natural and more sustainable methods for controlling diseases in horticultural crops while maintaining good postharvest quality. The effect of chitosan, a naturally occurring biopesticide, at different concentrations on the physico-chemical attributes and shelf life of “Sweet Cayenne” pepper (Capsicum annuum L.) was assessed. Freshly harvested mature green sweet peppers of uniform quality were dipped in different chitosan solutions (0, 0.5, 1.0, and 1.5%) for 3 min and stored at ambient conditions (26.51 ± 0.72 °C and 79.00 ± 5.98% RH) for 15 d. Physico-chemical parameters were evaluated at a 5-d interval. In all treatments, shriveling was significantly delayed with 1.5% chitosan at 10 d after treatment (DAT). Visual quality was better in 1.5% chitosan-treated fruit relative to the control at 10 and 15 DAT by up to 22 and 8%, respectively. The onset of decay was delayed in 1.5% chitosan-treated fruit for up to 4 d as compared to the untreated lot. The total soluble solids content of chitosan-treated fruit was lower than the untreated by up to 40% at 15 DAT, signifying delayed maturation. For the antioxidant properties, chitosan (1.5%) did not prevent the degradation of ascorbic acid and the DPPH scavenging activity but increased the total phenolic content at 15 DAT (by 51% compared to the control). These results suggest that chitosan coating, especially when applied at a higher concentration (1.5%) seems to show potential in preserving the quality and bioactive compounds of sweet peppers.