Effect of chitosan/nano-silica coating on the physicochemical characteristics of longan fruit under ambient temperature

A novel chitosan/nano-silica hybrid film was prepared using tetraethoxysilane as precursor by in situ sol-gel process, and characterized by transmission electron microscopy. Its effect on preservation quality of longan fruits (Dimocarpus longan Lour. cv Shijia) was investigated under ambient temperature. The present study revealed that the excellent semi-permeable film of chitosan/nano-silica markedly extended shelf life, reduced browning index, retarded weight loss and inhibited the increase of malondialdehyde amount and polyphenoloxidase activity in fresh longan fruit. In addition, the peroxidase activity of Ion-gan fruit coated with hybrid film was lower than that in other treatment fruits. Decreases in the contents of total soluble solids, titratable acidity and ascorbic acid were also significantly inhibited by hybrid films. These data indicated that the chitosan/nano-silica coating might provide an attractive alternative to improve preservation quality of fresh longan fruits during extended storage. (C) 2013 Elsevier Ltd. All rights reserved.