Studies on the starch-water interactions between partially gelatinized corn starch and water during gelatinization

The effect of moisture content on the interactions between water and partially gelatinized starch during gelatinization process was investigated. The interactions were probed using differential scanning calorimetry (DSC). The starch samples were partially gelatinized at 25 degrees C (S25), 64 degrees C (S64), 68 degrees C (S68) and 70 degrees C (S70) and the moisture contents were varied from 25% to 78% (w/w). The G endotherm was not observed and only the M1 endotherm was observed in S64, S68 and S70 in the entire moisture content range. The G endotherm was not observed and only the M1 endotherm was observed at higher peak temperature in S25 when the moisture content was below 30% (w/w). The melting temperature of M2 endotherm in S70 was the highest among all the samples tested in the entire moisture content range. At water content > 30% (w/w), S68 and S70 had lower amount of unfreezable water, while S64 had higher amount of unfreezable water.