Using differential scanning calorimeter (DSC), we have analyzed the gelatinization properties of flour and various types of starch, the relation between the gelatinization property and storage condition of flour, and the relation between the retrogradation characteristic and preservation state of bread.
1) The lower the water content in starch was, the slower the gelatinization and the higher the temperature of gelatinization were. A water content higher than 40% was necessary to carry out gelatinization
rapidly. Besides, the gelatinization properties were different in different types of starch. 2) Flour has been stored respectively in refrigerator, at room temperature or at high temperature and
high humidity. When stored at high temperature and high humidity, the discoloring of flour, generation of grain odor, and decrease of glutinosity when mixed with water were all found to be
significant. Nevertheless, the gelatinization property of wheat starch changed a lot with the time of storage but did not change significantly in different storage temperature or humidity. 3) Influence of storage temperature on the retrogradation of bread was analyzed using DSC. It was found that retrogradation of bread was mostly promoted by refrigerated storage but suppressed by frozen storage. The result of DSC analysis was correlated to the sensory evaluation of bread flavor,
suggesting the utility of DSC in the judgement of bread retrogradation.