Identification of protein types in Bambara nut seeds: perspectives for dietary protein supply in developing countries

Abstract

This study aims to identify the types of proteins in malted and dry Bambara groundnut seeds and through a comparative analysis, identify similarities and their known uses. Dry viable bambara seed was stored for five days to malt. The proteins in the dry and malted seed were subsequently extracted in potassium phosphate buffer pH 7.0 and precipitated with saturated ammonium sulphate. MudPit (multidimensional protein identification technology) and LC-MALDI TOF-TOF (liquid chromatography - matrix-assisted laser desorption ionization tandem time-of-flight) mass spectrometry were thereafter used to identify the different types of proteins. A total of ten and twelve different types of proteins present in other legume species were identified in the malted and dry seeds respectively from the 214 peptides isolated after searching 586 proteins of the genus Vigna. Seed storage protein B and vicilin were observed to be the major proteins common to both malted and dry seeds and are similar to Vigna luteola. Some of the other proteins observed showed amino acid sequence homology with Vigna radiata and Vigna unguiculata species. The following proteins BV1, Heat shock and Bowman-Birk Inhibitor (a protease), were observed only in the malted state. This information may enhance the appreciation of the nutritional and health benefits of the seed.