Profiling of Phenolic Compounds in Sprouted Common Beans and Bambara Groundnuts

Abstract

Consumption of sprouted legumes is a popular trend at household level in Africa at the moment. This study investigated the effect of sprouting on the phenolic phytochemicals of the red bambara groundnuts and red beans. Plant-derived phenolic compounds are important as antioxidants in our diet. Phenolic phytochemical profiling was performed using HPLC-PDA-ESI-MS and Folin Ciocalteu assay. There were noticeable changes in the phenolic profiles due to sprouting of the two legumes. The total polyphenol content increased by 1.3-fold and 3-fold after sprouting in red bambara groundnuts and red beans respectively. The HPLC-PDA-ESI-MS profiling of the methanolic extracts of the sprouts revealed new emerging compounds. In red bambara groundnuts, eleven new compounds emerged. The new compounds identified include caffeic acid hexoside, resveratrol glucoside, a caffeic acid derivative, naringenin and kaempferol glucoside. In red beans, eight new compounds emerged. Catechin glucoside, quercetin-3-O-glucoside, quercetin-3-rutinoside, luteolin hexoside, quercetin glucoside acylated and p-coumaric acid hexoside were new compounds identified. Sprouting therefore enhances the polyphenolic profiles of the two legumes.