Changes in Carbohydrate Metabolism in Coated Chestnuts during Storage

The changes in respiratory rate, amylase activity, starch content, reducing sugars and soluble sugars during storage at 5 degrees C were investigated in Chinese chestnut (Castanea mollissima Blume) treated with three different coatings, chitosan (1.5%), carrageenan (0.5%), and whey protein concentrate (5%). The results showed that the coatings reduced the decline of starch content and the increase of amylase activity. The respiratory rates in chitosan coated chestnuts were significantly lower than those in non coating ones, which was not observed in the fruits with carrageenan and whey protein concentrate. There were obvious relationships between amylase activity and starch content (R-2=0.8328), and between respiratory rate and reducing sugar content (R-2=0.6607) in chestnut, which were changed by the chitosan coating.