Physical properties of cross-linked and acetylated normal and waxy rice starch

Waxy and normal starches present wide biological diversity in their structu re. The objective of this study was to investigate the effect of chemical m odification on the physical properties of cross-linked and acetylated norma l NR and waxy WR, rice starch. Cross-linking increased shear stability and decreased swelling power and solubility of ness but decreased adhesiveness of NR and WR, but increased viscosity, pasting temperature, and heat of gel atinization of WR, and decreased pasting temperature and heat of gelatiniza tion of NR. Acetylation increased viscosity and solubility of NR and WR, wh ile it increased the swelling power of WR. Cross-linking increased hardness and adhesion of NR and WR gels, while acetylation increased hardness but d ecreased adhesiveness of the gels. Freeze-thaw stability results showed tha t both acetyl and cross-linking decreased retrogradation of NR, but increas ed it in WR.