Consumption of brown rice (BR) contributes to the implementation of the grain-saving policy and improvement of residents’ nutrient status. However, the undesirable cooking properties, poor palatability, and presence of anti-nutritional factors limit the demand of BR products. To enhance its quality, BR was solid-state fermented with single and mixed strains of Lb. plantarum, S. cerevisiae, R. oryzae, A. oryzae, and N. sitophila. Effects of solid-state fermentation (SSF) with different strains on the nutrition and sensory characteristics of BR were analyzed by spectroscopic method, chromatography, and sensory assessment. Contents of arabinoxylans, β-glucan, γ-oryzanol, phenolic, and flavonoid were significantly increased by 41.61%, 136.02%, 30.51%, 106.90%, and 65.08% after SSF, respectively (p < 0.05), while the insoluble dietary fiber and phytic acid contents reduced by 42.69% and 55.92%. The brightness and sensory score of BR significantly improved after SSF. Furthermore, cluster analysis (CA) and principal component analysis (PCA) were employed to evaluate BR quality. Three clusters were obtained according to CA, including BR fermented for 30 h and 48 h, BR fermented for 12 h, and the control group. Based on PCA, the best SSF processing technology was BR fermented with Lb. plantarum (0.5%, v/w) and S. cerevisiae (0.5%, v/w) at 28 °C for 48 h (liquid-to-solid ratio 3:10).

Hulless barley grain (HBG) was treated by solid-state fermentation (SSF) with various S. cerevisiae and L. plantarum inoculation ratios (1:0, 1:1, 1:2, 1:3, 0:1, 2:1, and 3:1). The effects of SSF on dietary fiber content and composition, amino acid composition, polyphenol and phenolic acid profiles, and in-vitro antioxidant capacities of HBG were investigated. After SSF, the soluble dietary fiber to insoluble dietary fiber ratio increased from 1/5 to 1/3, EAAI_egg and EAAI_adult increased from 95.25% and 70.44% to 110.40% and 81.65%, respectively, and total phenol content increased from 351.19 to 639.29 mg GAE/100g DW. In addition, the ABTS•+ radical-scavenging and total antioxidant capacities increased from 795.28 to 1986.10 μmol trolox/100 g DW, and 139.21 to 323.75 units/100 mg DW, respectively. These results indicate that SSF, particularly with S. cerevisiae/L. plantarum inoculation ratios of 1:1 and 2:1, is a potential technology to improve the nutritional quality and antioxidant capacity of HBG.