Modification of Starches with Different Amylose/Amylopectin-Ratios Using the Dual Approach with Hydroxypropylation and Subsequent Acid-Thinning—Impacts on Morphological and Molecular Characteristics

Abstract

Commercial starches with different amylose (AM)/amylopectin (AP)-ratios (waxy potato: WxPS, regular potato: PS, high AM corn: HACS) are hydroxypropylated (HP, pilot plant scale, two levels) and subsequently acid-thinned (AT, laboratory scale) to produce dual-modified samples. The gradation of the molar substitution (MS) obtained is significant for each starch basis. Investigation by means of scanning electron microscopy reveals a basically intact granular structure with surface defects. The molecular properties are comprehensively characterized using size exclusion chromatography-multi angle laser light scattering-differential refractive index detection (SEC-MALS-DRI) and corresponding conventional calibration (SEC-cal-DRI). The evaluation of the molecular data (MS and weight average molar mass, Mw) by means of statistical analysis (ANOVA) identifies statistically significant impacts with respect to the starch type, the substitution level, and the AT treatment.