Structural and physicochemical characteristics of lycoris starch treated with different physical methods

Abstract

The effects of microwave treatment (MT), heat-moisture treatment (HMT) and autoclaving treatment (GT) on the structural and physicochemical characteristics of lycoris starch (LS) were investigated. The HMT-LS and GT-LS particles were larger and rougher with block-like characteristics compared to the LS particles. The XRD results revealed that HMT and GT converted native starch (A-type) into B-type starch. The density of the starch crystallization zone after HMT and GT was higher than that of LS, while MT had the weakest effect. The solubility and swelling power of MT-LS, HMT-LS and GT-LS were significantly (p < 0.05) lower at 65 and 95 °C, but opposite trends were observed at 55 °C. The RVA viscograms for MT-LS, HMT-LS, and GT-LS showed a lower breakdown and setback value compared to that of LS, reflecting stronger starch aggregations and lower retrogradation tendencies. Additionally, both G' and G″ of the treated starch were lower, which indicated weaker gel structures.

Keywords: Lycoris starch; Physicochemical properties; Rheological properties; Structural characteristics.