Changes of phenolics of litchi fruit during postharvest storage.
Zhang, D. L.; Quantick, P. C.;
Acta Horticulturae Year: 2000 Issue: No. 517 Pages: 427-433 Ref: 17 ref.
2000
บทคัดย่อ
Litchi (cv. Huaizhi) fruits were stored at ambient temperature and at 4 deg C for 7 days and 35 days, respectively, to investigate the changes in free phenolics, bound phenolics, total phenolics, PPO (polyphenol oxidase [catechol oxidase]) activity, PAL (phenylalanine ammonia lyase) activity, and browning of the fruit peel during storage. A 0.03-mm-thick polyethylene film and TBZ (0.1% thiabendazole) were used in packaging and decay control of the fruit during storage. With the increase of ambient storage time, the contents of total phenolics and free phenolics decreased continuously, while bound phenolics remained at the same level. However, with storage at 4 deg C, the content of total phenolics decreased continuously and the content of bound phenolics decreased slightly during the first 5 days and then returned to and stabilized at the original level. The content of free phenolics increased slightly during the first 5 days and then decreased. With the increase of browning, the contents of tot
al phenolics and free phenolics decreased, while bound phenolics remained at a steady level whether the fruits were stored at ambient temperature or 4 deg C. There were gradual increases in both PPO and PAL activities in the fruits stored at both ambient temperature and 4 deg C and then decreases corresponding to a fall in free phenolics. Therefore, it is suggested that free phenolics are the main source of browning substrates during storage of litchi fruits; PPO activity is closely related to the level of free phenolics while PAL has some contribution to the level of free phenolics.