Saponins Do Not Impede the Bioaccessibility of Minerals and Fat-Soluble Vitamins from Different Quinoa Genotypes

Quinoa seeds contain high amounts of minerals, carotenoids, and tocochromanols (vitamin E) and can be classified into bitter and nonbitter genotypes based on their saponin contents. Saponins may form complexes with minerals and cholesterol, but their impact on the bioaccessibility of minerals, carotenoids, and tocochromanols from quinoa is unknown. We therefore subjected the seeds of 12 quinoa genotypes (n = 6 bitter, n = 6 nonbitter) to in vitro digestion and quantified the concentrations of the nutrients in digesta. Bitter and nonbitter quinoa did not differ in digestive stability, solubility, bioaccessibility, and micellar efficiency of these compounds. Mineral bioaccessibility was low, whereas that of the lipid-soluble compounds was low to medium. The mean micelle sizes and negative surface charges of mixed micelles did not differ between bitter and nonbitter quinoa seeds. In conclusion, the saponins in quinoa do not appear to affect micellar characteristics or to impair the bioaccessibility of minerals, carotenoids, and tocochromanols.