Salicylic acid maintains membrane stability and reduces pericarp browning in litchi

Abstract

Rapid pericarp browning generates unmarketable litchi fruit leading to huge postharvest losses to growers and traders. Salicylic acid (SA) at three different concentrations (0.4, 0.8, and 1.2 mM) was tested as a postharvest dip treatment to ascertain the effect on fruit quality and storage behaviour of litchi. Freshly harvested litchi fruit 'Shahi' were dipped in the solutions, maintained at 10°C for 30 min, and thereafter surface dried before packing in perforated and unsealed polythene bags. They were then stored under refrigerated conditions (6±1°C and 80-90% RH). SA-treated (1.2 mM) fruit maintained significantly higher membrane stability index (78.44) compared to control (67.64) over 22 days of storage. SA treatment also resulted in maintenance of higher anthocyanin content compared to control during storage. Untreated fruit had hardly 12.5% marketable fruits (˂50% browning) after 18 days. The corresponding figure in case of SA-treated (1.2 mM) fruit was 68%, thereby indicating that SA treatment helps in reduction of pericarp browning in litchi. Also, the incidence of decay was only 6.25% in fruit treated with 1.2 mM SA, a significant reduction in decay from control (43.75%) after 18 days of storage. No significant differences due to SA treatment were recorded with respect to changes in fruit quality parameters such as soluble solids concentrate and titratable acidity. Our results suggest that salicylic acid at 1.2 mM can be integrated as a part of hydro-cooling of litchi fruit to reduce pericarp browning and fruit decay.