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

Waxy and normal starches present wide biological diversity in their structure. The objective of this study was to investigate the effect of chemical modification on the physical properties of cross-linked and acetylated normal (NR) and waxy (WR) rice starch. Cross-linking increased shear stability and decreased swelling power and solubility of NR and WR, but increased viscosity, pasting temperature, and heat of gelatinization of WR, and decreased pasting temperature and heat of gelatinization of NR. Acetylation increased viscosity and solubility of NR and WR, while it increased the swelling power of NR, and decreased the swelling power of WR. Cross-linking increased hardness and adhesiveness of NR and WR gels, while acetylation increased hardness but decreased adhesiveness of the gels. Freeze-thaw stability results showed that both acetylation and cross-linking decreased retrogradation of NR, but increased it in WR.