Browning inhibition on fresh-cut chestnut kernel by exogenous nitric oxide

P>The potential usage of nitric oxide (NO) as a powerful anti-browning agent in fresh-cut chestnut kernels was investigated. Chestnut kernels were dipped in 0, 1, 5 or 10 mu m NO solutions for 10 min, respectively, and then stored at 20 degrees C. Changes of browning index and colour were evaluated, while content of total phenols, activities of polyphenol oxidase (PPO) and peroxidase (POD) and individual phenolic compounds were measured. The results showed that NO treatment delayed browning and lightness of chestnut kernels and 5 mu m NO treatment had the best control effect compared with others. PPO and POD activities were inhibited and total phenolic content was increased in NO-treated fruit, and 5 mu m NO significantly increased the content of catechin, chlorogenic acid, syringic acid, phloretic acid and ferulic acid but inhibited that of tannic acid. However, it had no significant effect on caffeic acid.