Study On The Effects Of Na₂S₂O₅ Treatment On The Postharvest Phyiological And Biochemical Changes And Storage Of Chestnut

Using Zhen'an chestnut (Castanea mollissima Blume) as experimental material, the physiological and biochemical changes and storage effects of the chestnut were studied under different concentrations of Na2S2O5 and different treated time to provide theorestical basis and technical guide. The results are as follows:(1) With 2h 2% Na2S2O5 soluion treatment, the respiratory intensity was inhibited significantly, and the consumption of soluble sugar was reduces so that the quality of chestnut was maintained better than that of other treatments. But the inhibitory effects were weakened with prolonging time of Na2S2O5 soluion treatment. The trend of changes in the respiratory intensity was similar to that of non-respiration climacteric fruits.(2) With Na2S2O5 soluion treatments, the Amylase activity was inhibited significantly so that the decompose rate of starch was slowed down and the changes of soluble sugar and reducing sugar were alleviated; and the decreasing of soluble protein content and the loss of VC were mitigated. Prolonging the time of treatments played a certain role in maintaining the content of starch and VC.(3) With 2h 2% Na2S2O5 soluion treatment, the decreasing of the activity of CAT, POD, SOD was inhibited, but the effect of 2h 4% treatment was on the contrary. Prolonging the time of treatment had no significant effects on the decreasing of the activity of CAT, POD, SOD.(4) The PPO activity was inhibited significantly with Na2S2O5 soluion treatments. The longer treated time and the higher concentration of Na2S2O5 solution, the inhibitory effects were better. The PPO activity was significantly negatively correlated with the VC content.(5) The MDA content decreased or maintained with treatment, while that increased with 2h 4% treatment. The relative conductivity was inhibited with 2h 1% Na2S2O5 soluion treatment. Prolonging time of Na2S2O5 treatments decreased the inhibitory effects. MDA content was significantly positively correlated with the relative conductivity.(6) With 2h 1% and 2% Na2S2O5 soluion treatments, the water content and the weight loss rate had no significant difference with those of the control. 2h 4% and 6h 2% treatment accelerated the water loss of the chestnut so that the weight loss rate increased. With 4h 2% Na2S2O5 soluion treatments, the water content of chestnut decreased significantly.(7) With 2h 1% and 2% Na2S2O5 soluion treatments, the rot rate of chestnut decreased significantly; the chestnuts with other Na2S2O5 soluion treatments were infected by penicillium so the rot rate increased at different degree. The reason needs further study.