Effects of annealing on structural and physicochemical properties of amaranth, quinoa, and taro starches: From a viewpoint of branch scattering

Small-granule starch has many advantages for advanced food applications. Annealing could expand the advantages of small-granule starch by modifying their properties without disrupting the granular integrity. The study compared the annealing of three small-granule starches (from amaranth, quinoa, and taro) with that of conventional starches (from potato and maize). The impacts of annealing on the properties were diverse among small-granule starches and also the controls. The diversity was collectively affected by the molecular and supramolecular structures of these starches. In this study, the role of the branched backbone of amylopectin in modulating the annealing-induced changes, in addition to that of short- and long-range ordered structure, was revealed by a novel method developed based on the building block backbone model and “branch scattering” theory. Taro starch exhibited interesting changes in supramolecular structure and properties (thermal properties and temperature-dependent viscoelastic properties), which were associated with an unique change in the distribution of branches in its granules. The proportion of small branched building blocks in the Naegeli dextrins increased in taro starch after the annealing. The results provided novel insight into the barely changed short-range order but improved long-range order of taro starch upon annealing. The study demonstrated that variations in molecular structure strongly influence the extent and nature of annealing-induced changes in starch supramolecular order and functionality. • Effects of annealing on different starches diverse. • Annealed amaranth and potato starches had improved short- and long-range order. • Long-range order of annealed taro starch improved but its short-range order doesn’t. • Annealing altered the scattering of branches in taro starch granule.