Gelatinization and Pasting Properties of Waxy and Non‐waxy Rice Starches

Abstract

Abstract Gelatinization and pasting properties of diverse rice types grown in two locations were examined by differential scanning calorimetry (DSC) and rotational rheometry, respectively. The data were compared to previously reported molecular starch properties for these samples: specifically, amylose content, starch molecular weight ( M w ), and amylopectin side‐chain‐length distributions. Significant correlations were observed between amylose content, starch M w , and the weight degree of polymerization of the long side chains of amylopectin F 1 (DP w ) and many of the gelatinization and pasting properties measured. Higher amylose content corresponded with increased gelatinization onset ( T o ) and peak temperatures ( T p ), pasting onset and peak temperatures, and decreased peak and trough viscosity. Starch M w correlated negatively with T o , T p , pasting onset, and peak temperature and positively with peak, trough, final, and breakdown viscosity. Amylopectin with DP w 59‐78 of F 1 (DP w ) correlated with increased T o , T p , pasting onset and peak temperature, and decreased peak, trough, final and breakdown viscosity. Pasting properties were also somewhat related to DP w 21 of shorter side chains of amylopectin ( F 2 (DP w )). Significant correlations between F 2 (DP w ) and peak, final, and breakdown viscosity were observed ( r = −0.447*, −0.391*, −0.388*, peak, final, and breakdown viscosity, respectively).