Bioactive phenolic compounds of cowpeas (Vigna sinensis L.). Modifications by fermentations with natural microflora and with Lactobacillus plantarum ATCC 14917

In this work we have determined the phenolic composition of raw cowpeas (Vigna sinensis L) of the variety Carilla by HPLC/PAD/MS and have studied the effect of fermentation, both spontaneous and with Lactobacillus plantarum ATCC 14917, on the phenolic compounds. This variety contains mainly ferulic and p-coumaric acids esterified with aldaric acids, together with the cis and trans isomers of the corresponding free acids. Hydroxybenzoic acids such as gallic, vanillic, p-hydroxybenzoic and protocatechuic were also found, along with flavonols such as amyricetin glucoside, mono- and diglycosides of quercetin and a quercetin diglycoside acylated with ferulic acid. Fermentation, both spontaneous and inoculated, modifies the content of phenolic compounds, but differently in each case. The antioxidant activity as free radical-scavenging activity has also been evaluated. Fermentation followed by heating has been shown to be a very effective process to increase the functionality of this variety of V sinensis. For this reason, this cowpea variety could be used as an ingredient to obtain high value-added flours.The authors are grateful to the Spanish Comision Interministerial de Ciencia y Tecnologia (AGL2000- 1609-C02) and also to the Comunidad Autonoma de Madrid for a predoctoral grant.Peer reviewe