Abstract
In a study of the physical and chemical properties of rice, the effects of the various temperatures on the pH values, reducing sugar content, water-soluble dry matter content, enzymatic activities of brown rice and respiration rate of unhulled rice were determined during continuous drying of fresh unhulled rice.
The higher the temperature of drying, the smaller were the pH values, and the amounts of watersoluble dry matter content of brown rice. Another practical significance was the gradual loss in reducing sugar, which affects taste, at high temperatures such as 50°C, 60°C and 70°C. The maximum content of reducing sugar of rice was recognized at 30°C or 40°C. These were accompanied by changes in alpha- and beta- amylase activities.
Residual catalase and peroxidase activities were also decreased at high temperatures. Respiration rate of unhulled rice was high at 60°C.
From the data now obtained, it was assumed that optimum temperatures of drying rice would be 30°-40°C in practice.
