Effects of Soluble and Insoluble Dietary Fiber from Corn Bran on Pasting, Thermal, and Structural Properties of Corn Starch

In this study, the effects of various concentrations (1%, 2%, 3%, 5%) soluble dietary fiber (SDF) and insoluble dietary fiber (IDF) from corn bran on the pasting, rheological, and thermal properties and the microstructure of corn starch (CS) are investigated. The findings show that the addition of dietary fiber inhibits the short-term retrogradation of starch and decreases the relaxation time of weakly bound water. The SDF and IDF reduce endothermic enthalpy from 11.79 to 8.81 and 8.80 (J g(-1)), respectively (p < 0.05). The addition of SDF significantly inhibits the gelatinization of starch (p < 0.05), which reduces viscosity during CS pasting. In addition, 5% of SDF significantly (p < 0.05) reduces the wavenumber ratio value (1047 cm(-1)/1022 cm(-1)) from 0.906 to 0.861 and decreases the strength of the CS gel from 653.29 to 75.66. The CS-SDF gel shows a sheet-like network structure, while in the CS-IDF gel, IDF is embedded in a network structure. This research further expands the understanding of the interaction between dietary fiber and starch during processing and allows the improvement of high dietary fiber product quality.

Automated summary

The effects of soluble and insoluble dietary fiber from corn bran on the properties and microstructure of corn starch were investigated in this study. The addition of dietary fiber inhibited starch retrogradation and decreased the relaxation time of water. Both soluble and insoluble dietary fiber reduced the enthalpy of corn starch. Soluble dietary fiber significantly inhibited starch gelatinization and decreased viscosity.