Studyies Of Cold Shock And Ultraviolet-C Treatments On Postharvested Qualities Of Chinese Olive

To explore the effects of cold shock and ultraviolet-C treatments on postharvested qualities of Chinese olive. In this paper, Firstly,’Changying’was choosed as material, and the cold shock critical condition was studied. The optimum treatment (improved the fruit postharvest fresh qualities) on’Changying’ fruit of cold shock treatment time (30 min) and ultraviolet-C (UV-C) dose (2.4 KJ/m2) were selected. Then different stage fruit (I (160 d after flowering), II (167 d after flowering) å'Œâ…¢ (178 d after flowering)) and different varieties fruit (’Changying’ and ’Fulan No.1’) were choosed as materials; effects of cold shock treatment (30 min) and ultraviolet-C (2.4 KJ/m2) treatment on postharvest qualities were investigated; and the mechanism was studied. The conclusions were as follows:1. The relative conductivity was increased with the increase of cold shock time, and had a significant difference at 0.05 level when the time was up to 1 hour. So 1 h was choosed as the critical condition before the cell membrane damaged.2. The experiment results of cold shock treatment (10～50 min) and ultraviolet-C (0.6-4.8 KJ/m2) showed that:cold shock 30 min,2.4 KJ/m2 of ultraviolet-C could reduce the content of polyphenol; delayed the decline of fruit soluble total sugar content; could retain low polyphenol-sugar ratio, improved the fruit taste, palyed a positive role on the improvement of fruit fresh qualities.3.’Chang ying’ fruit was more better on postharvest storage, especially the stage â…¡fruit(167 d after flowering). Cold shock treatment could delay the fruit rot time; improved good fruit rate; and inhibited the fruit browning of ’Fu Ian No.1’, significantly.4. Cold shock treatment (30 min) could activate the fruit PPO activity; inhibited the decline of SOD activity; improved the contents of endogenous antioxidant substances (AsA and GSH), enhanced the antioxidant level of the fruit; lowed respiration rate of ’Changying’ and delayed the respiratory peak of’Fulan No.1’; decreased MDA content during the storage, inhibited membrane peroxidation; delayed the senescence of’Changying ’and ’Fulan No.1’, and prolonged fruit storage period.5. Effects of ultraviolet-C in Chinese olive fruit were related to the maturity and variety. Ultraviolet-C (2.4 KJ/m2) could activate the olive fruit PPO activity. For ’Chang ying’(stage â… I andâ…¢), ultraviolet-C treatment improved the fruit AsA content and SOD activity; delayed the fruit rot time; improve good fruit rate; and prolonged fruit storage period. However, ultraviolet-C treatment speed up respiration rate and improved the respiratory peak of’Fulan No.1’; lowed the fruit AsA content and SOD activity, reduced the antioxidant level of the fruit, accelerated the fruit browning.6. Cold shock and ultraviolet comprehensive treatment had no difference on ’Chang ying’ fruit preservation. And lowed the fruit AsA content and SOD activity of ’Fulan No.1’, declined the antioxidant level of the fruit, accelerated the fruit browning.