The heated cornstarch granules were swollen and partly ruptured, and then glucose chains were leached out from starch granules. The granule sizes of the samples at pH 6.0, 5.0, and 4.0 with the pH adjusted before gelatinization were almost the same as those of the control. However, the number of glucose chains at pH 5.0 and 4.0 (blue region in Fig. 2) (web version only) was apparently more than that of the control. Therefore, there are many entanglements of glucose chains as compared with those of the control, and these networks of glucose chains lead to higher viscosities. Thus, the viscosity of starch samples, where the pH is between 5.5 and 3.6, was greater than that of the control. Many small granules were observed for the sample with pH 3.5 as compared with the control and the samples at pH 6.0, 5.0, and 4.0. Almost all granules were broken at pH 3.0. Decreases in the viscosity by lowering pH below 3.6 may be due to the collapse of many starch granules or the hydrolysis of glucose chains by adding acids.