Some characteristics of acetylated, cross-linked and dual modified Indian rice starches

Starches from broken rice grains derived from three varieties (PUSA-44, PR-106, and PR-114) were modified by hydroxypropylation with propylene oxide and esterification with adipic acid anhydride and/or vinyl acetate. Degree of substitution and acetyl contents (in parentheses) was relatively low; ranges between 0.02 (0.53%) and 0.12 (3.09%) for hydroxy-propylated cross-linked and acetylated starch samples. The acetylation and dual modification of starches increased the paste clarity, solubility, swelling power, sediment volume, and gel strength but decreased the gel elasticity in all the three varieties. However, the adhesiveness increased only upon dual modification in PUSA-44 and decreased in other two varieties. Cross-linking reduced the solubility, swelling power, sediment volume, and gel elasticity while increased the paste clarity, gel strength and adhesiveness. The physico-chemical characteristics of relatively high amylose variety PUSA-44 among three varieties were significantly lower than those from varieties with low amylose content whereas PUSA-44 had shown improved gel properties as compared to other two varieties.