Structure and physicochemical properties of starches from six accessions of the genus Pueraria in China

Kudzu (Pueraria lobata) root contains abundant starch, but the physicochemical properties of kudzu starch are not well understood. In this study, we compared the compositions and physicochemical properties of starches isolated from six Pueraria accessions in China. Caige starch exhibited the highest purity (96.99 %) and amylose content (24.76 %), while Yege starch contained higher levels of puerarin (493.37 μg/g) and daidzein (38.68 μg/g). All kudzu starches were rich in resistant starch, with RS2 content ranging from 38.61 % to 46.22 % and RS3 content from 3.59 % to 6.04 %. The granules of kudzu starches varied in morphology, with Yege starch featuring larger polygonal granules. The kudzu starches presented either A-type or A-type-like C-type diffraction patterns. Caige starch had a higher IR2 value (1.28), higher gelatinization temperatures, wider temperature ranges, and greater enthalpy changes. Yege (JX) starch exhibited the highest peak viscosity but the lowest setback viscosity and pasting temperature. Fenge starch showed the highest final viscosity, with Fenge (ZJ) starch demonstrating the highest crystallinity (25.7 %) and IR1 value (0.80). These results indicated that kudzu starches derived from various Pueraria species possess unique structural and physicochemical properties, which provide significant potential for applications in food and other industrial fields.