Nitric oxide reduces pericarp browning and preserves bioactive antioxidants in litchi

• Nitric oxide donor, sodium nitroprusside (SNP) treatment reduced pericarp browning and extended shelf life of litchi fruit, during storage at ambient condition.
• Fruits treated with SNP (2.0 mM) maintained 42% higher anthocyanin content and preserved bioactive compounds like phenolics, ascorbic acid and antioxidant capacity, compared to control.
• SNP treatment minimized weight loss, decay percentage, and malondialdehyde content in fruit.
• TSS and titratable acidity also maintained higher in SNP treated fruits.

Pericarp browning is the most important postharvest problem in litchi (Litchi chinensis Sonn.), which reduces the commercial acceptability and shelf life of fruit. In the present study, effect of nitric oxide (NO) on pericarp browning, bioactive antioxidants, and shelf life of fruit was investigated. Fruits were treated with the NO donor, sodium nitroprusside (SNP; 0.5 mM, 1.0 mM or 2.0 mM) by the immersion method, and stored at ambient condition for 8 days. SNP treatments, at all concentrations, significantly reduced pericarp browning in which the most remarkable effect was obtained with 2.0 mM SNP showing 30% lower pericarp browning and 42% higher anthocyanin content than control. The levels of total phenolics and antioxidant capacity of treated fruits were 50% and 31% higher respectively in relation to untreated ones. Throughout the storage, SNP treatment was highly effective in reducing weight loss, malondialdehyde (MDA) content, as well as delaying loss of total soluble solids, titratable acidity, and ascorbic acid in fruits with minimum decay (10%) giving an extended shelf life up to 8 days. Pericarp browning was negatively correlated with anthocyanin content, total phenolics content, antioxidant capacity and shelf life whereas it was positively correlated with weight loss, MDA content and decay percentage. These findings confirm that 2.0 mM SNP could be used as a treatment to reduce pericarp browning of litchi before storage.