Effects of dual-strain fermentation on physicochemical properties of Rosa roxburghii Tratt and coix seed beverage

This study delved into the feasibility of fermenting Rosa roxburghii Tratt and coix seed beverage (RRTCSB) using dual-strain fermentation. The impact of Trametes versicolor and Lactiplantibacillus plantarum LB12 fermentation on RRTCSB's physicochemical properties was investigated. Post-fermentation, the beverage's color clarified and brightened, displaying an appealing hue. Even the concentrated malic acid, which contributes both sourness and astringency, decreased from 21.227 ± 0.151 mg/mL before fermentation to 14.067 ± 0.090 mg/mL after fermentation, indicating a reduction of approximately 30%. Regarding the beverage's characteristics, the retention rate of vitamin C was about 75%, resulting in a final content of 2.9 mg/mL. Additionally, the polysaccharide content consistently increased. Specifically, during T. versicolor fermentation, the polysaccharide content experienced an approximate 72% increase. The final polysaccharide content reached 2.85 mg/mL. Initially declining and then rising, γ-aminobutyric acid (GABA) increased by 17% during the dual-strain fermentation. The final content of GABA reached 5.12 mg/100 mL. Fermentation, particularly with T. versicolor, gradually enhanced the beverage's hypoglycemic activity. Ultimately, this study successfully demonstrated the feasibility of introducing T. versicolor and L. plantarum for fermenting RRTCSB, yielding an improved novel beverage.