Postharvest hydrogen sulfide infiltration modulates antioxidative metabolism and increases shelf life of litchi

Litchi fruits are highly perishable in nature and start deteriorating immediately after harvest, which can be characterized by pericarp browning. In this study, the effect of exogenous hydrogen sulfide (H2S) on different biochemical events linked to pericarp browning and oxidative damage in litchi were assessed at 1 day interval during 4 days storage. Fruits were vacuum infiltrated with H2S (1 and 2 mM) at ambient temperature. The untreated control fruits were subjected to dipping in distilled water and were stored at ambient (28 degrees C, RH 70-75%) conditions. H2S treatment maintained the postharvest quality of litchi fruit during storage by alleviating oxidative damage and modulating enzymatic activities. Control fruits lost their postharvest quality at initial storage with visible pericarp browning and other biochemical degradative changes when compared with treated fruits. Postharvest H2S (2 mM) infiltration significantly reduced weight loss, pericarp browning and ROS production (H2O2 and O-2(-)) as well as suppressed the activity of polyphenol oxidase (PPO) and peroxidase (POD) enzymes and exhibited higher TSS, titratable acidity, total phenolic, anthocyanin, antioxidant activities, membrane integrity, phenylalanine ammonia lyase (PAL) activity and reduced quinone and malondialdehyde (MDA) accumulation. Thus, H2S (2 mM) infiltration treatment could be suggested to enhance the storage life of litchi fruits at ambient storage condition.