Antioxidant Activities of Selective Gluten Free Ancient Grains

Abstract

Ancient grains were known for special nutritional values along with gluten free qualities. Amaranth, quinoa, teff, and buckwheat flours were evaluated for pasting properties, water holding capacities, phenolic contents, and antioxidant activities (free and bound). They all had higher water holding capacities than wheat flour. Amaranth, quinoa, and teff showed higher pasting viscosities than wheat flour. Buckwheat flour had the highest free, bound and total phenolic contents among the flours in all aqueous extracts. The bound phenolic contents were higher than the free phenolic contents regardless of the solvents with the exception of water extraction of quinoa and buckwheat. The free phenolic compounds for all four flours were highest in water extract, and least in 100% ethanol. Bound antioxidant activities were much higher than the free antioxidant activities regardless of solvents for all products. The free antioxidant activities from water and 50% ethanol were higher than 100% ethanol. In contrast, more bound phenolics were extracted with 100% ethanol than water and 50% ethanol. Our study suggested that the total phenolic contents and antioxidant activities of grains could be underestimated in the literature without considering the bound phenolic compounds. These ancient grains have nutrition, antioxidants, and textural qualities suitable for functional foods.