Abstract
BACKGROUND: The storage life of litchi is limited due to pericarp browning and decay. Modified atmosphere packaging (MAP) showed promising results for ensuring quality retention. However, to improve the efficiency of MAP the integrated treatment of a chitosan coating and MAP was investigated.
RESULTS: The effect of chitosan (1.0 g L^−1^) + MAP was compared with MAP (control), and was effective in preventing decay, browning and retaining the pericarp colour in the cultivar McLean's Red. Chitosan (1.0 g L^−1^) + MAP significantly reduced polyphenol oxidase (PPO) and peroxidase (POD) activity, retained membrane integrity, anthocyanin content and prevented the decline of pericarp colour values during storage. The POD activity was greater than the PPO activity in the cultivars McLean's Red and Mauritius. The two cultivars differed in anthocyanin content and the activity of oxidation enzymes. The gas compositions within the packages were compared between chitosan at 1.0 g L^−1^ and 20.0 g L^−1^ concentration for both cultivars. Chitosan (20.0 g L^−1^) + MAP lowered the respiration during storage in both cultivars compared to 1.0 g L^−1^ + MAP.
CONCLUSION: The McLean's Red cultivar is better suited for chitosan (1.0 g L^−1^) + MAP integrated treatment than is Mauritius in retaining overall quality. Copyright © 2009 Society of Chemical Industry