In previous papers, the cooking rate parameters of potatoes were differed. It this paper, we were measured the cooking ratios of potato by using the constant velocity penetration method under the hot condition of cooked samples and the cooled condition.
The values of cooking ratio of the samples during the cooking process were differed to the measuring temperature. The cooking-rate equation obtained under the hot condition was as follows:
dx/dθ=A・exp[—E/ (Rg・T)] (1-x)^n
A=6.398 x 10^8 min-1, E=7.50 x 10^3 cal/g-mol, n=1
where, x[—]: cooking ratio, θ[min]: cooking time, T[°K]: cooking temperature, Rg=1.987 cal/(g-mol・°K). The value of activation energy obtained was lower than the value of 1.50 x 10^4 cal/g-mol obtained in previous paper which measured the cooking ratio under the cooled condition. We can consider that the softening behavior of potatoes occured by the cooking phenomena and the measuring temperature changes, and conclue that the softening behavior occured for the samples of high measuring temperature method during the uncooked temperature.