Response surface methodology for investigating structure–function relationship of grain legume proteins

Abstract

Effect of physicochemical properties and secondary structure conformation, on the functional properties of protein concentrates prepared from grain legumes was investigated using response surface methodology. Appropriate models were built on the basis of the best subset technique. Oil-holding capacity was mainly influenced by the secondary structure of proteins, particularly unordered structure, β-sheet, and β-turn. Protein solubility depended on secondary structure and surface hydrophobicity of proteins, and solubility decreased with increasing hydrophobicity. Interaction between solubility and hydrophobicity was significant for emulsifying activity, and EA increased with increasing solubility and hydrophobicity. High emulsion stability of legume proteins necessitated high β-turn secondary structure proportion, solubility, and hydrophobicity. Protein unfolding, particularly high unordered, and β-turn structures and high solubility were required for high foaming ability of legume proteins. In summary, the importance of this study was to increase the utilization of grain legume proteins in the food and non-food industry. Practical applications It is important during food processing or when using an underutilized grain legume protein source as ingredient or supplement in the formulation of food products, to predict the functional properties of the protein. Functional properties are important for the consumer acceptance of food product. The physicochemical properties of protein such as surface hydrophobicity and secondary structure could be used as a basis to predict functionality. In this connection, this study provided effects of the variation of physicochemical properties and secondary structure of grain legume proteins on oil-holding capacity, solubility, emulsifying and foaming properties. The aim of this study was to enhance the utilization of grain legume proteins as nutritional and functional ingredient.