Abstract
The retrogradation of starches in foods heated by electronic range, electric rice cooker and gas oven was investigated.
The quality of foods was determined by measuring starch gelatinization ratio, X-ray diffraction pattern of starch and sensory test.
For this research, rice and sweet potatoes were selected as starch rich foods and they were stored at 6°C or -20°C after cooking. The frozen foods were thawed at 30°C.
The starch gelatinization ratio of foods heated in the electronic range in storage was more decreasing than that of foods heated with the electric rice cooker or the gas oven. Crystalline structure in X-ray diffraction pattern of starch appeared in the early storage at 6°C of rice heated in the electronic range, but it was not observed in the precooked and thawed rice.
X-ray diffraction pattern of precooked frozen sweet potatoes was slightly different by cooking methods.
As a result of sensory test, quality of the precooked frozen rice by electronic range was significantly inferior than that by the electric rice cooker, but the precooked frozen sweet potatoes did not show significant difference in quality by cooking methods.
