Changes of Composition and Nutrition Value of Some Gluten Free (Pseudo)cereals by Addition of Carotenogenic Yeast Cell Homogenate.

Gluten-free cereals and pseudocereals such as oats, quinoa, and buckwheat are widely used as bases for functional foods due to their protein quality, minerals, fiber, and polyphenols. However, they contain relatively low levels of some vitamins. This study evaluated the enrichment of cereal porridges with a cell-free homogenate of the carotenogenic yeast Rhodotorula toruloides (RT) as a natural strategy to enhance their nutritional value. Model porridges prepared from gluten-free oats, quinoa, buckwheat, and their blends were supplemented with 0%, 5%, or 10% R. toruloides homogenate (RTh). Samples were analyzed for antioxidant capacity (ABTS), lipid-soluble vitamins and provitamins (HPLC), fatty acid composition (GC-FID), approximate prebiotic potential, and cytotoxicity using the MTT assay on Caco-2 cells. The addition of RTh significantly increased antioxidant properties, with the highest value observed in buckwheat porridge with 5% RTh (1.9 mg TE/g DW). Lipid-soluble metabolites were detected only in enriched samples, reaching up to 420 µg/g DW ergosterol and 300 µg/g DW total carotenoids, mainly torularhodin. Quinoa porridges showed the highest PUFA content, whereas RTh was rich in oleic acid. Enrichment increased MUFA levels and improved the fatty acid profile. Approximate prebiotic potential was strongest in oat-quinoa blends. Cytotoxicity remained low, with most IC50 values above 2000 µg/mL. Supplementation with 5% R. toruloides homogenate effectively improves antioxidant and lipid composition of gluten-free porridges while maintaining low cytotoxicity.