Modification of Starches with Different Amylose/Amylopectin Ratios Using the Dual Approach with Hydroxypropylation and Subsequent Acid Thinning—III: Impacts on Gel Characteristics

Abstract

Starches with different amylose (AM)/amylopectin (AP) ratios (waxy potato: WxPS, regular potato: PS, high AM corn: HACS) are subjected to hydroxypropylation (HP, two levels) and subsequent acid‐thinning (AT) to produce dual modified samples. Pastes of the starch samples (native; single modification: HP and AT, respectively; dual modification) are prepared by pressure cooking to two different starch concentrations (C) (6% and 9% w/w) and systematically investigated especially in terms of light transmittance (T) and specific gel characteristics after long‐term cold storage (168 h at 5.5 ± 1.5 °C). The data are evaluated statistically (i.a. analysis of variance, ANOVA) and significant effects are identified. Indeed, the gel strength correlates positively with the AM content of the starch and C, but the HP eliminates the ability of the starch to gel in most cases. The improved Tgel due to HP is accompanied by extensive loss of mechanical strength in most cases, which is not compensated by the partial molecular degradation via AT. Hence, a synergistic effect of both modifications is not revealed. The synergistic implementation of a starch with the desired properties by preparing mixtures is not revealed during the present examinations.