Rheological, textural, and pasting properties of A- and B-type wheat starches in relation to their molecular structures.

ABSTRACT

A- and B-type wheat starches have significant differences in rheological, textural, and pasting properties; however, the structure-property relationship is not fully revealed. Herein, the physicochemical characteristics and molecular structures of A- and B-type starches isolated from three wheat varieties with different apparent amylose contents (2.41%-27.93%) were investigated. A-type starches exhibited higher pasting viscosities, relative crystallinity, onset gelatinization temperatures, and enthalpies, while B-type starches had wide gelatinization temperature ranges. B-type starches had lower resistant starch contents than their A-type counterparts, but B-type starches formed more stable gels and had a lower tendency to retrograde, resulting in lower hardness, storage (G') and loss (G'') moduli but higher tan δ values. A-type starches had lower contents of short amylose (100 ≤ X < 1000) and amylopectin chains (DP 6-12) than B-type. These findings elucidated the differences in molecular structures between A- and B-type starches, which can contribute to their effective application.