Effects of inulin with different degrees of polymerization on the structure, properties and digestibility of rice starch
Ye Yuan, Luyan Liao, Renxiang Yang, Sijie Zhang, Jiayu Zhang, Jinyan Zhang, Yiying Wu, Zengmin Kuang, Weiguo Wu, Yu Zhang
Abstract
The effects of three inulins (IN) with different polymerization degrees on the structure, properties and digestibility of rice starch (RS) were investigated. The results showed that the viscosity, breakdown, and setback values of the composite systems decreased. Compared to pure starch, the gelatinization enthalpy of composite systems significantly decreased from 9.54 J/g to 9.13 J/g, 9.05 J/g, and 8.79 J/g, while the retrogradation enthalpy after 14 d storage declined from 4.58 J/g to 3.44 J/g, 3.72 J/g, and 3.85 J/g. The addition of IN significantly reduced the relative crystallinity and formation of ordered structures in the composite systems after 14 d of storage. Digestibility analysis revealed a significant decrease in rapidly digestible starch (from 69.63 % to 45.48 %, 48.38 %, and 50.00 %) and increases in slowly digestible and resistant starch contents. The effects depended on IN's polymerization degree and concentration, with 3.0 % short-chain IN demonstrating the most pronounced improvement in starch properties.