Metabolite profile of Bambara groundnut (Vigna subterranea) and dawadawa (an African fermented condiment) investigation using gas chromatography high resolution time-of-flight mass spectrometry (GC-HRTOF-MS)

Metabolite profile provides an overview and avenue for the detection of a vast number of metabolites in food sample at a particular time. Gas chromatography high resolution time-of-flight mass spectrometry (GC-HRTOF-MS) is one of such techniques that can be utilized for profiling known and unknown compounds in a food sample. In this study, the metabolite profiles of Bambara groundnut and dawadawa (unhulled and dehulled) were investigated using GC-HRTOF-MS. The presence of varying groups of metabolites, including aldehydes, sterols, ketones, alcohols, nitrogen-containing compounds, furans, pyridines, acids, vitamins, fatty acids, sulphur-related compounds, esters, terpenes and terpenoids were reported. Bambara groundnut fermented into derived dawadawa products induced either an increase or decrease as well as the formation of some metabolites. The major compounds (with their peak area percentages) identified in Bambara groundnut were furfuryl ether (9.31%), bis (2-(dimethylamino)ethyl) ether (7.95%), 2-monopalmitin (7.88%), hexadecanoic acid, methyl ester (6.98%), 9,12-octadecadienoic acid (Z,Z) and 2-hydroxy-1-(hydroxymethyl)ethyl ester (5.82%). For dehulled dawadawa, the significant compounds were palmitic acid, ethyl ester (17.7%), lauric acid, ethyl ester (10.2%), carbonic acid, 2-dimethylaminoethyl 2-methoxyethyl ester (7.3%), 9,12-octadecadienoic acid (Z,Z)-, 2-hydroxy-1-(hydroxymethyl)ethyl ester (5.13%) and maltol (4%), while for undehulled dawadawa, it was indoline, 2-(hydroxydiphenylmethyl) (26.1%), benzoic acid, 4-amino-4-hydroximino-2,2,6,6-tetramethyl-1-piperidinyl ester (8.2%), 2-undecen-4-ol (4.7%), 2-methylbutyl propanoate (4.7%) and ë-tocopherol (4.3%). These observed metabolites reported herein provides an overview of the metabolites in these investigated foods, some of which could be related to nutrition, bioactivity as well as sensory properties. It is important to emphasize that based on some of the metabolites detected, it could be suggested that Bambara groundnut and derived dawadawa might serve as functional foods that are beneficial to health.