Total free phenolic content and health relevant functionality of Indian wild legume grains: Effect of indigenous processing methods

In the present study, the total free phenolic content, antioxidant activity and type II diabetes-related enzyme inhibition properties of methanolic extracts of certain promising immature wild type under-utilized legume grains, such as Abrus precatorius L., Acacia leucopholea Willd., Bauhinia variegata L., Canavalia gladiata (Jacq.) DC., Cassia floribunda Cav., Entada scandens Benth., Indigofera linifolia (L.f.) Retz., Mucuna pruriens (L.) DC., Sesbania bispinosa (Jacq.) Wight. and Tamarindus indica L., collected from South India, were investigated. The total free phenolic content of the investigated samples ranged between 4.24 and 8.75 g catechin equivalent/100 g extract dry matter (DM). The extracts showed promising ferric reducing/antioxidant power (FRAP, 110-280 mmol Fe[II]/g extract), antioxidant activity (inhibition of β-carotene degradation, 32.37-57.69%) and radical scavenging activities against 2,2-diphenyl-1-picryl-hydrazyl (DPPH, 49.97-81.31%) and superoxide (42.21-61.65%). In all the studied seed materials, sprouting + oil-frying treatment revealed significantly higher total free phenolic content, antioxidant and type II diabetes relevant functionality, than open-pan roasting or soaking + cooking. Hence, sprouting + oil-frying is recommended as valuable processing method for the use of wild legume grains in the local production of supplementary foods with the potential to manage type II diabetes in the malnourished socio-economically weaker section of Indian population.