Thermal properties
Table 1 shows the eVect of acetic acid on the thermal analysis of the properties of starch. The onset (To), peak (Tp), and Wnal (Tc) temperature of gelatinization were lower in the presence of acetic acid although the enthalpy (H) was hardly aVected by acetic acid. This shift to lower tem- perature for gelatinization indicated that starch gelatinized easily with the addition of acetic acid.
Hibi (2002) also reported that the endothermic peak temperature of rice starch was lower in the presence of acetic acid (equivalent to 0.33 M). It is assumed that acceleration of water absorption of starch by adding acetic acid
shown in Fig. 1a promoted the hydration of starch, leading to the enhancement of starch gelatinization.