Differences in the chemical composition and physicochemical properties between brown rice kernels and brown rice flours after Lactobacillus fermentation and their impact on the qualities of brown rice noodles

The objective of this research was to characterize Lactobacillus fermented brown rice kernels (BRK) and flours (BRF) at different durations and to evaluate the qualities of brown rice noodles (BRN) produced from them. It was observed that there was a difference in susceptibility to fermentation between BRK and BRF. The fermentation of BRK showed a comparatively lower decrease in pH value and starch content, while exhibiting a greater efficacy in reducing dietary fiber content compared to BRF. In addition, fermented BRK showed a smaller increase in the gelatinization temperature, enthalpy and loss factor (tanδ), along with a lesser decrease in pasting viscosity, storage modulus (G′), loss modulus (G″), shear stress and apparent viscosity when compared to fermented BRF. Moreover, BRN made from fermented BRK, especially at 18 h, showed a smoother microstructure and significantly (P < 0.05) improved cooking, textural and eating properties compared to those made from native and fermented BRF. Furthermore, the starch digestibility in BRN was reduced by fermentation of both BRK and BRF. In conclusion, Lactobacillus fermentation of BRK proved to be effective in simultaneously improving the textural quality and RS content of BRN. • Fermentation of brown rice kernels (BRK) was efficient for fibre degradation. • Fermentation of BRK improved the smoothness of rice noodles. • Fermentation of BRK improved the cooking, texture and eating properties of rice noodles. • Fermentation of BRK reduced starch digestibility of rice noodles. • Rice noodles made from fermented BRK at 18 h had the highest sensory score.