VELLINGIRI VADIVEL, HANS KONRAD BIESALSKI
University of Hohenheim, Department of Biological Chemistry and Nutrition, Germany
In the present study, effect of certain indigenous processing methods on the levels of bioactive compounds of an under-utilised legume, velvet bean (Mucuna pruriens) was investigated. Ten different accessions of velvet bean seeds collected from various agro"=ecological locations of the world exhibited a wide variability with respect to the levels of total free phenolics (5.24-8.65gper100gDM), tannins (1.77-3.49g per 100gDM), L-Dopa (4.30-6.23g per 100gDM) and phytic acid (1.17-2.37g per 100gDM). Significantly higher level of total free phenolics and tannins was noticed in VB seeds collected from Zimbabwe, while Guatemala VB accession registered maximum level of L-Dopa. Among the different processing methods attempted in the present study, soaking in tamarind solution + cooking and soaking in alkaline solution + cooking treatments were found to reduce significant level of total free phenolics by 24-46% and 36-65%, respectively. Tannins were reduced at maximum level only under soaking in alkaline solution + cooking treatment (24-52%). Significant level of loss of L-Dopa (6-67%) was noticed under all the treatments of the present study. However, none of the treatments resulted in significant level of loss of phytic acid in velvet bean seeds. Further, sprouting + cooking as well as open"=pan roasting were found to be optimal in retaining higher levels of bioactive compounds. Hence, such viable processing methods could be recommended for the consumption of velvet bean seeds as a natural source of health beneficial bioactive compounds, in addition to high nutritive potential.
Keywords: tannins, bioactive compounds, L-Dopa, Mucuna pruriens, phytic acid, processing methods, total free phenolics, velvet bean