Cold storage influences the postharvest pericarp browning and quality of litchi

Occurrence of postharvest pericarp browning and rapid decay limit the postharvest storage life of litchi fruit. Effect of low temperature storage on the physico-chemical characteristics of two commercial litchi cultivars 'Bedana' and 'Serai' stored at 5 degree C for 0, 7, 14, 21 and 28 days were investigated. Incidence of pericarp browning, disease severity and fruit physicochemical characteristics were determined immediately after each removal. During cold storage fruit firmness (15-5.1 N), weight loss (7.06-1.92%), aril: stone ratio (15.3-11.7) and sensory values of fruit decreased, whereas fruit pericarp browning index (0.33-3.25), postharvest disease index (0.5-2.4) and fruit cracking (0.08-1.16%) increased. Fruit weight loss, pericarp browning and disease severity were higher in 'Serai' than 'Bedana' fruit. The fruit of cv. 'Bedana' showed better aril: stone ratio (23.07), firmness (2.1 N), pH (4.15), SSC (19.04%), TA (0.14%), total sugars (12.11%) and ascorbic acid (44.8 mg 100 g-1) contents than 'Serai'. Fruit flavour, texture and aroma changed rapidly during cold storage in 'Serai' than 'Bedana'. The pH of fruit juice showed slightly increasing trend during the whole span of storage, while SSC (20.4-17.4%), TA (0.23-0.05%), ascorbic acid (55-32.8 mg 100g-1), total sugars (13.5-10.5%) and phenolics (0.71-0.45 mug 100 g-1) showed decreasing trend. Litchi cv. 'Bedana' exhibited higher total phenolic contents (0.71 mug 100 g-1) than 'Serai' (0.55 mug 100 g-1). The fruit of cv. 'Bedana' were found superior having less weight loss, pericarp browning index and disease severity index, with higher aril: stone ratio, flavour, texture, aroma, pH, SSC, TA, ascorbic acid, total sugars and phenolic contents. Results suggest that postharvest pericarp browning and fruit quality deterioration can be delayed by cold storage.