Effect of Freeze–Thaw Cycles on Physicochemical and Functional Properties of Ginger Starch

Abstract

Ginger (Zingiber officinale Roscoe.) starch is a waste product generated during the extraction of bioactive compounds from ginger. This study aimed to treat ginger starch with different freeze–thaw cycles and explore the effect on the functional components, physicochemical properties, and structural properties of ginger starch. The results of the study showed that as the number of freeze–thaw cycles increased, the content of resistant starch, amylose, total starch, and recrystallization in ginger starch increased significantly (p < 0.05). Freeze-dried ginger starch exhibited a C-type crystal structure in the X-ray diffraction pattern. The Fourier-transform infrared spectroscopy results also showed that the value of A1047/1022 increased, indicating that the freeze–thaw cycle would increase the degree of starch recrystallization. In terms of physical and chemical properties, compared with gelatinized starch, freeze–thawed starch had low swelling power, high solubility, low peak viscosity and breakdown, indicating higher thermal stability. In conclusion, freeze–thaw treatment can promote the formation of resistant starch from ginger starch and reduce starch hydrolysis, reflecting the potential of low–GI foods. We hope that ginger starch can be used as a raw material for new applications in functional foods.