Causal relations among starch hierarchical structure and physicochemical characteristics after repeated freezing-thawing

In this study, hierarchical structural and characteristic changes of starches isolated from repeated freezingthawing (FT) frozen dough were evaluated to understand the causal relations among intrinsic structures and physicochemical characteristics. The surface of FT-treated starch granules displayed pores and cracks, and more severe rupture was obtained as the increase of freezing-thawing cycles. Furthermore, the lamellar structure, crystalline and ordered molecular structure (i.e., short-range ordered molecular and helical structures) of starch were also destructed after FT. And these structural amorphization facilitated the interactions between water molecules and starch molecular chains, the leaching of starch molecules, the entanglements and interactions between amylose and amylopectin, eventually elevating the swelling power, solubility and characteristic viscosity of starch. Also, FT treatment led to an increase in storage modulus (G') and a decrease in loss tangent (tan delta), which indicated the formation of strong gel network structure.

Automated summary

The study evaluated hierarchical structural and characteristic changes of starches isolated from repeated freezing-thawing frozen dough, showing that freezing-thawing cycles led to pores, cracks, and destruction of the lamellar structure, crystalline structure, and ordered molecular structure of starch. This structural amorphization facilitated interactions between water molecules and starch chains, leading to changes in physicochemical characteristics such as swelling power, solubility, and gel network formation.