Influence of extraction methods on functional properties of protein concentrates prepared from South African bambara groundnut landraces

Summary: Functional properties of protein concentrates prepared from three bambara groundnut landraces using acid precipitation and salt solubilisation methods were evaluated. The protein content of bambara grains (26-27%) was similar for the three landraces. The acid precipitation gave a much higher yield of protein concentrates (52%), which were also high in protein (79%) compared to the salt solubilisation method (yield: 25%, protein content: 57%). Functional properties of proteins were more influenced by the methods of preparation rather than the landraces. Protein concentrate prepared by salt solubilisation method showed higher emulsifying (63-66%), foaming (53-57%), water (1.4-2.0 mg mL-1) and oil absorption properties (2.2-2.6 mg mL-1) than the acid-precipitated concentrates (53-57%, 63-66%, 2.0-2.7 mg mL-1, 1.4-1.7 mg mL-1). The foaming capacity and stability of all the protein concentrates decreased with increasing pH from 3 to 8. Salt solubilisation may be the most appropriate method for the enhanced functionality and utilisation of bambara groundnuts' protein concentrates.