The Effects of Postharvest Low Oxygen Treatment on the Storage Quality of Chestnut
Wang Guixi, Liang Lisong, and Sun Xiaozhen ( The Research Institute of Forestry, The Chinese Academy of Forestry, Beijing 100091, China; Weinan Institute of Agricultural Sciences Shanxi Province, Weinan 715501, China)
In this paper, the effects of postharvest low oxygen (0 -5% ) treatment on the cold storage quality of chestnut (Castanea mollissima Blume) 'Dahongpao' at 0℃ were studied. The results were as follow: (1) Treatment duration and oxygen concentration were the main factors affecting the quality, the chestnut become off-flavor if it was treated for more than 20 days and the oxygen concentrations were below 2%. Though the index of off-flavor was alleviated during the 120 days cold storage, the flavor was not completely recovered at the final. (2) Low oxygen treatments induced the increase of ADH activity and alcohol concentration , the longer treatment time and lower oxygen concentration, the higher ADH activity and alcohol concentration. When the treated chestnuts were stored at 0℃or 120 days, the ADH activity and alcohol concentration were recovered to the level of control. (3 ) Low oxygen treatments affected the metabolism of starch and soluble sugar. 0-2% oxygen could stimulate the decomposition of starch, while 3% -5% oxygen could slow down the decomposition rate. The treatment of 1% -3% oxygen maintained higher content of soluble sugar than the other treatment. (4) The mean decay rate of 0 -2% oxygen treatments was 10% , the control was 7% , meanwhile the decay rate of 3% -4% oxygen treated for 20 days or 5% oxygen treated for 25 days were only 1% at the end of 120 days cold storage. In general, 3% oxygen treated for 20 days was the best treatment to keep the storage quality of chestnut among the low oxygen treatments.