Germination as a Bioprocess: Unraveling Its Impact on the Nutritional and Flavor Profile in Four Quinoa Beer Varieties

Quinoa contains all the essential amino acids for human nutrition, which is also known to be gluten-free. In this research, black, red, white, and gray quinoa were germinated to ferment beers. The effects of germination as a bioprocess on the nutritional profile, anti-nutrients, and flavor development in quinoa beers were systematically investigated, and a comprehensive comparison was made with two commercially popular beers. The results indicated that the optimal germination time for quinoa in beer production was 48 h. Germination significantly increased the contents of polyphenols (255.9 mg/L in white quinoa beer) and flavonoids (404.34 mg/L in red quinoa beer), which enhanced the antioxidant activity of the beers. Furthermore, the levels of protein and γ-aminobutyric acid were elevated through germination. Notably, germination markedly improved the potential nutritional accessibility of the beers through reducing the anti-nutritional factors, including phytic acid, tannins, and trypsin inhibitor. In terms of flavor, quinoa beers developed a unique and pleasant aromatic profile, characterized by compounds such as ethyl octanoate, ethyl 9-decenoate, and ethyl pentadecanoate, which distinguished them from commercial beers. In conclusion, germinated quinoa can serve as a high-quality brewing material for producing beer with enhanced nutritional value, reduced anti-nutrients, and improved flavor characteristics.