Effect of hydrocolloids on the pasting and rheological characteristics of resistant starch (type 4)

Abstract

The pasting and rheological properties of resistant starch-type 4 (RS4) and hydrocolloid mixtures were characterized at 2 different concentrations (0.1 and 0.5%, w/v). When RS4 was mixed with 2 hydrocolloids (pectin and xanthan gum), there was the overall tendency that both swelling power and solubility of the RS4 suspensions significantly increased. Steady shear measurements showed that the RS4 and hydrocolloid samples exhibited shear-thinning behaviors which could be well characterized by the Power law model. A dramatic increase in the viscosity by xanthan gum was also observed, compared to pectin. In addition, dynamic oscillatory tests indicated that the RS4 and hydrocolloid mixtures exhibited more elastic properties with less frequency dependence, compared to RS4 alone. Also, the viscosities of the RS4 suspensions during pasting increased with increasing concentrations of the hydrocolloids used and these effects became significantly dominant when xanthan gum was incorporated.