Investigation on the influence of pectin structures on the pasting properties of rice starch by multiple regression

This work investigated effects of the galacturonic acid content (GA), degree of methoxylation (DM), degree of amidation (DA) and molecular weight (M-w) of pectin on the pasting properties of rice starch (RS). Pectins with varying structures were selected randomly. Different pectins when added to RS showed significant differing (p < 0.05) influences on pasting properties of RS. Multiple regression analysis was adopted to establish equations between structural characteristics of pectin and pasting properties of RS. The obtained equations had a good fit (all R-2 >= 0.936), and relative errors of pasting properties for prediction group were very close to the coefficient of variation (except breakdown). The contribution of the specific pectin structural characteristic on the change of the pasting properties of RS was also evaluated. DM was greatly correlated with peak and trough viscosity. Breakdown was strongly affected by DA and GA. Two primary factors that affected setback were the Mw and GA. Furthermore, peak time was mainly influenced by DA. (C) 2016 Elsevier Ltd. All rights reserved.