Processing of velvet bean (Mucuna pruriens var utilis) by fermentation

"Velvet bean or Mucuna (Mucuna pruriens var utilis) was pre-treated and subjected to fungal or bacterial fermentation to produce three foods, namely Mucuna tempe, Mucuna condiment and Mucuna-fortified weaning foods. pH, total crude protein, soluble constituents as well as the residual levels of the toxic principle, L-Dopa, were evaluated. pH increased in mould and basic fermentations while it decreased in lactic acid fermentation. Total crude protein remained fairly constant in all types of fermentations. Levels of soluble solids and soluble protein increased dramatically in fungal and basic fermentations. Non-protein nitrogen followed the same tren. Pre-treatment of the bean before fermentation provided the most effective means of reducing L-Dopa in velvet bean. In the treatment that reduced about 90% (89.95%) of L-Dopa, the beans were boiled for 45 min, dehulled, soaked for 12 or 24 hr with removal and replacement of water after 12 hr, then boiled in fresh water for an additional 45 min. Further reduction was obtained during fungal fermentation, suggesting the production of an L-Dopa-degrading enzyme. All the fermented products contained low levels of LDopa (often <0.1% dry wt). Production of Mucuna tempe and Mucuna-fortified weaning foods is recommended at household level as a way to alleviate protein-energy malnutrition. However, large-scale production is limited by the dehulling process."