Chitosan biopolymer improves the fruit quality of litchi (Litchi chinensis Sonn.)

Chitosan (CHT) is a natural compound that has been used to control postharvest pathogenic diseases due to its capability of eliciting natural defense responses in plants. The aim of this study was to investigate the effect of foliar CHT application on yield and quality of the litchi fruit. Chitosan was applied by spraying on to fruit and foliage just after fruit set four times at 7-day intervals with four varying doses viz. 100, 250, 500, and 1,000 µg L−1 and a control (0 µg L−1). Although the application of CHT had no significant effect on the size of the fruits (length and width), the total contents of phenolics, flavonoids, and ascorbic acid and the antioxidant activity of litchi fruit arils were significantly increased in CHT-treated fruit compared with the untreated control. The highest phenolic, flavonoid, and ascorbic acid contents were 334 µg gallic acid g−1, 881 μg quercetin g−1, and 178 µg g−1, respectively, in fruits treated with 500 µg L−1 CHT. However, the highest antioxidant activity (622 μg butylated hydroxytoluene g−1) was recorded in 250 µg L−1 CHT-treated fruits. Our findings revealed that the application of low doses of CHT in a litchi orchard might improve fruit quality by increasing the content of antioxidants and antioxidant activities.