Effects of different souring methods on the protein quality and iron and zinc bioaccessibilities of non-alcoholic beverages from sorghum and amaranth

Souring by lactic acid fermentation and lactic acid acidification as well as inclusion of amaranth were explored as ways of improving the protein quality and iron and zinc bioaccessibilities of non-alcoholic sorghum-based beverages. The bioaccessible iron and zinc increased by 128–372%, 24–194%, respectively, in the fermented and chemically acidified beverages compared to the beverages without fermentation or acidification. The protein digestibility, reactive lysine, and bioaccessible iron in sorghum-amaranth beverages increased by 14–58%, 24–52% and 34–64%, respectively, compared with the 100% sorghum beverages. Both fermentation and acidification with lactic acid have the potentials for improving the nutritional quality of cereal-based foods as a means of combating protein malnutrition and iron and zinc deficiencies.