Evaluation of an alternative low-resource soy protein production method

Abstract

Mechanically expelled soy cake (MESC) is a valuable source of protein and other nutrients; however, this product stream is underutilized for human consumption, especially in low-resource settings such as the Sub-Saharan Africa (SSA) region. Additionally, MESC still contains oils, which are prone to oxidation. Through collaborative partnerships with scientists like Dr. Keshun Liu, USDA, ARS, and Dr. Kephas Nowakunda, NARL, we piloted a low resource method to make soy protein concentrate (SPC) that can be widely used by processors in developing economies. Using this method, oil content, oxidized byproducts, phytic acid, and oligosaccharides are reduced, while increasing protein content to almost 63% db. In this session, we demonstrate an alternative low-resource method to produce SPC from MESC and evaluate their nutritional quality and oxidative stability. We also present early sensory findings and hypothesize on potential uses and benefits of SPC products and ingredients in emerging markets. The SPC materials produced were characterized based on their protein, oil and phytic acid contents. Thiobarbituric acid reactive species using malondialdehyde (MDA) as standard and peroxide value were assessed in SPC meal and oil extracted from SPC, respectively, to evaluate oxidation status in comparison with raw materials.With this alternative less resource-demanding method, SPC with a protein content of ~63% db and with lower oil (50% less) and phytic acid (70% less) contents and higher stability due to lower peroxide value (50% less) and MDA (50% less) contents than the original MESC can be made from defatted or low-fat soy flour using locally-available materials and equipment. This is beneficial because with this alternative method, the utilization of SPC for human consumption in SSA can be improved by expanding its incorporation into various food products including extruded snacks, composite flours, porridges, and bakery products.