Combined effect of acids and shellac coating on pericarp browning, enzymatic activities, and biochemical attributes of litchi fruit during storage

Abstract

Pericarp browning in litchi fruits affects its marketability; therefore, it needs to be addressed using low-cost postharvest interventions. Current research focuses on the use of different organic acids viz hydrochloric acid (0.25 and 0.5 M), citric acid (0.1 and 0.2 M), ascorbic acid (0.1 M and 0.2 M) along with shellac wax to study pericarp browning and quality characteristics of litchi fruits under cold storage conditions (2–3°C, 90%–95% RH). Among the treatments, HCl (0.5 M) + shellac wax resulted in extended shelf life of 14 days with minimum loss in physiological weight, highest firmness, and minimum decay. Browning index was recorded minimum in 0.25 M HCl + shellac-treated litchi fruits. Minimum enzymatic activities of polyphenol oxidases (PPO), peroxidase (POD), and phenylalanine ammonia lyase (PAL) assay and maximum retention of bioactive compounds were recorded in HCl + shellac-treated litchi fruits. Overall, HCl–shellac proved to be most effective in maintaining quality and prolonging shelf life of litchi. Novelty Impact Statement Hydrochloric acid (0.5M)–shellac wax combination improved shelf life of litchi fruit by 14 days under cold store conditions. Browning index in litchi pericarp reduced significantly upon application of 0.25M hydrochloric acid and shellac wax. Organic acid dip retarded enzymatic activities viz. polyphenol oxidase (PPO), peroxidase (POD), and phenylalanine ammonia lyase (PAL) in litchi pericarp.