Mixed microbial fermentation with Lactiplantibacillus plantarum and Saccharomyces cerevisiae increases the nutritional bioactive components and flavor substances of pigmented quinoa

Quinoa is a nutrient-rich pseudocereal, but its application in foods is largely restricted by its anti-nutritional factors and undesirable flavor. This study investigated the effects of mixed microbial fermentation at 30 °C for 72 h on the physicochemical properties, nutritional bioactive components, and flavor substances of pigmented quinoa. The mixed microbial fermentation significantly decreased the contents of starch, protein, bound phenols, and saponins in quinoa with different colors, but increased the soluble dietary fiber content to 4.34 %–4.56 % and the free phenol content to 3.15–4.36 mg GAE/g DW. Moreover, fermented black quinoa exhibited 109 % and 297 % enhancement in DPPH radical scavenging capacity and total reducing capacity, respectively, with improved antioxidant activity after simulated digestion. Volatile profiling revealed distinct flavor characteristics between fermented white and red/black quinoa. In summary, the mixed fermentation can significantly improve the bioactive components in quinoa, providing a theoretical basis for its application in the food industry.