EFFECTS Of OXALIC ACID TREATMENT On QUALITY Of KIWI FRUIT During STORAGE

Effects of oxalic acid treatment on AsA-GSH circle、ethanol metabolism、 nutritional quality and ripening in kiwi fruit "Bruno"(Actinidia deliciosa.cv.) and "White"(Actinidia eriantha.cv.) were investigated in this paper. Kiwi fruit dipped in50mmol·L-1oxalic acid (pure water as control) for10min, respectively, and then stored at25℃for indicators measuring. The main results were as follows:The fresh colour was improved by oxalic acid treatment. The ethylene release peak postponed and respiration rate reduced in treated kiwi fruit, and slowed fruit softening and delayed ripening also presented in treated fruit. White showed longer storage life as compared to Bruno kiwifruit, mainly due to lower ethylene release and respiration rate.The content of Vc, soluble solids (SSC), total soluble sugar (TSS), etc were improved with oxalic acid treatment. The content of tartaric acid, oxalic acid, malic acid, acetic acid; Na, Mn, etc were increased as the nutrition improvement in treated kiwi fruit. In addition, the alcohol dehydrogenase (ADH) activity was reduced with oxalic acid treatment, which decreased the conversion of ethanol, effectively decreased the taste of alcohol in Bruno.AsA-GSH cycle was the emphasis of this thesis, we found that:L-galactono-1,4-lactone dehydrogenase (GalLDH) was not only a key enzyme in high AsA level maintenance in kiwi fruit growth, but also playing an important role in postharvest. The AsA level in White was over ten times in Bruno’s, which could mainly attribute to higher GalLDH activity in White fruit during storage, and6～8times higher than that in Bruno’s. Moreover, the dehydroascorbate reductase (DHAR), timely coverted DHA to AsA, still maintained higher activity in White fruit.