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

•The chitosan/nano-silica hybrid is synthesized and applied to loquat storage at 5 °C.•The hybrid film enhances contents of reducing sugars and activates sugar signals.•Antioxidant activity of loquat fruit is enhanced by the hybrid film.•The hybrid film improves chilling resistance and quality of loquat fruit.

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 °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 (O2−) 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/nano-silica coating was effective in enhancing chilling tolerance and providing a longer storage life with acceptable external and internal quality in loquat fruit.