Effects of chitosan/nano-silica on postharvest quality and antioxidant capacity of loquat fruit during cold storage

Loquat (Eriobotrya japonica Lindl.) fruit has a very short shelf-life during ambient temperature storage, and is susceptible to cold storage appearing chilling injury symptoms. The effect of chitosan/nano-silica coating on chilling tolerance in white-flesh loquat fruit (cv Baiyu) stored at 5 degrees C for 40 d was investigated. In comparison with control fruit, internal browning and weight loss in chitosan/nano-silica treated fruit were significantly delayed. Likewise, the decrease of total soluble solids (TSS) and titratable acidity (TA) was also inhibited. Glucose and fructose contents increased from 11.31 to 12.76 g kg(-1) and from 33.20 to 44.37 g kg(-1), respectively. The increase of reducing sugars contributed to the improvement of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) activities, reaching the peaks of 623510.12, 462371.21 and 41114.35 U kg(-1), respectively. Enhanced activities of antioxidant enzymes markedly alleviated the generation of superoxide anion (O-2 center dot) and hydrogen peroxide (H2O2). Low levels of malondialdehyde (MDA) and membrane permeability in chitosan/nano-silica treated fruit were also detected, ranged from 4.35 to 8.31 mmol kg(-1) and from 24.32 to 43.45%, respectively. Moreover, activities of phenylalanine ammonia-lyase (PAL), polyphenoloxidase (PPO) and lipoxidase (LOX) were also much lower than those in treatment alone and control fruit. Our results indicated that the use of chitosan/nanosilica coating was effective in enhancing chilling tolerance and providing a longer storage life with acceptable external and internal quality in loquat fruit. (C) 2016 Elsevier B.V. All rights reserved.