Physicochemical Properties of Hydroxypropylated Apios Starches

Apios ( Medikus), also called the potato bean, Indian potato, or groundnut, belongs to the legume family, and is widely distributed across eastern North America. Apios starch was hydroxypropylated, and its physicochemical and structural characteristics were investigated in this study. The starch was extracted by alkali precipitation method, and hydroxypropylated apios starch (HPAS) was prepared using propylene oxide at concentrations of 2.5, 5, 7.5, and 10% (v/w). X-ray diffraction of native apios starch and HPAS revealed the presence of the typical 'A' type of cereal starch. Additionally, the hydroxypropylation affects the relative crystallinity of the starch. The swelling power and solubility of apios starch increased after hydroxypropylation. Gelatinization parameters were obtained using differential scanning calorimetry. The gelatinization temperature of native starch is 69°C, whereas that of HPAS-10% is 52.94°C. This suggests that HPAS is suitable for preparing food items requiring enhanced gelatinization.