Properties and metabolite profiling of Bambara groundnut flour as affected by different food processing conditions

Bambara groundnut are legumes with high nutritional value, quality, and potential for various food development, after undergoing processing. This study investigated the influence of different processing (fermentation, infrared heating, malting, and roasting) methods and conditions on the swelling power, FTIR spectra, colour, and metabolite composition of the flour samples. Fermentation and malting improved the swelling power, while infrared heating and roasting reduced swelling power. This property is important in food applications such as baking, where it can improve texture, volume, and moisture retention of the final product. Infrared heating increased lightness but reduced redness and browning index of the flour samples slightly, while roasting reduced lightness but increased the redness and browning index of the flour samples significantly, due to chemical reactions between the constituents of the Bambara groundnuts. Furthermore, fermentation and malting produced metabolites such as alcohols, esters, and ketones, while roasting resulted in the highest diversity of metabolites including phenols, benzenes and carboxylic acids. Differences and similarities were also observed among the processed and unprocessed Bambara groundnut in terms of their functional groups, with roasted samples having higher intensities, implying a higher density of strong bond interactions caused by the roasting process. The study revealed that varying processing methods and conditions can modify the quality and functionality of Bambara groundnut flour, and provide insights into its potential application in food products. This will especially be useful for developing new and improved products from Bambara groundnut, which could cater for increasing demand for gluten-free products, and functional foods, among consumers.