Pasting and gelation behaviors and in vitro digestibility of high-amylose maize starch blended with wheat or potato starch evaluated at different heating temperatures. (October 2022) - Yuan, Tommy Z.
Abstract: Different approaches have been adopted to overcome the inherent shortcomings of native starches, and blending of different native starches has attracted much attention due to the "clean-label" feature and the low processing effort and cost. In the current study, we blended high-amylose maize starch (HA7) with wheat (WHE) or potato (POT) starch at 1:1 ratio (dry weight basis; dwb) and then comprehensively examined their thermal properties, pasting and gelling behaviors over the heating temperature range of 95–140 °C, and in vitro digestibility in comparison with three individual starches. With an excess amount of water (starch:water = 1:3), gelatinization of individual starches generally appeared to be independent in the two starch blends. An exceptionally low percentage of retrogradation was observed for gelatinized HA7-WHE blend during cold storage, which could be partially ascribed to the formation of a large amount of amylose-lipid complexes (ALC). Greater resistance to thermal degradation and thixotropic breakdown during pasting at 120 °C was found with HA7-WHE blend when compared with HA7-POT blend. Both starch blends could form gels with moderate strength (74.3–109.4 g) after cooking at 120 and 140 °C. The determined resistant starch (RS) and slowly digestible starch (SDS) contents of water-boiled HA7-WHE blend were higher than the calculated values when assuming simple additivity of the two starches. The interactions at both granular and molecular levels and the presence of ALC were responsible for the reported unique techno-functional attributes of HA7-WHE blend, which rendered it suitable for diverse food and industrial applications. Graphical abstract: Image 1 Highlights: More amylose-lipid complex in high-amylose (HA7)-wheat (WHE) starch blend (1:1 dwb). Gelatinized HA7-WHE blend had the least %retrogradation (9.2%) of all the starches. HA7-WHE blend showed strong resistance against high-temperature cooking at 120 °C. Starch blends had moderate gel strength (74.3–109.4 g) after 120 and 140 °C cooking. Water-boiled HA7-WHE blend showed enhanced in vitro enzymatic resistance.