Study of phytic acid and protein contents during velvet beans (Mucuna pruriens) tempe production with variation of size reduction and fermentation time

Abstract

Rokhmah LN, Anam C, Handajani S, Rachmawati D. 2009. Study of phytic acid and protein contents during velvet beans (Mucuna pruriens) tempe production with variation of size reduction and fermentation time. Biofarmasi 7: 1-9. Velvet bean is one species of Leguminoceae containing phytic acid. The advantage of phytic acid is for antioxidant. Nevertheless, phytic acid has shortage, i.e. antinutritional. Phytic acid has characteristic that it can be provided from protein to form insoluble complex of phytate and protein. The formation of phytate-protein complex causes decreasing protein availability for human body so reducing the nutrition value of the food product. The aims of this research were to determine the influence of size reduction of velvet beans seed (Mucuna pruriens) and the fermentation time on the contents of phytic acid and soluble protein on the production of velvet bean (Mucuna pruriens) tempe. This research is a factorial experiment that arranged in a Randomized Complete Design (RCD) with two experimental factors including size reduction (3 kinds) and the time of fermentation (5 kinds). Every 12 hours fermentation time for three kinds of velvet beans seed size, the lowest phytic acid and the highest soluble protein were showed by velvet bean tempe from grinded seeds. On the fermentation time of 36 hours for three kinds of seeds size resulted in a lowest phytic acid during fermentation, i.e. 3.32 mg/g, 1.98 mg/g, and 1.16 mg/g, respectively. The contents of highest soluble protein during fermentation obtained on fermentation for 36 hours were 19.51 mg/g, 23.73 mg/g, and 24.89 mg/g. The fermentation time and the size of velvet bean seeds affected on phytic acid and soluble protein contents of velvet bean tempe. The longer fermentation time of velvet bean tempe caused a lower phytic acid content and a higher soluble protein content. The smaller size of velvet bean seeds on tempe caused a lower phytic acid content and a higher soluble protein content. The velvet bean tempe of grinded seeds with 36 hours fermentation had the lowest of phytic acid content and the highest of soluble protein content of all samples with the variation of reducing size and the duration of fermentation. The optimally time fermentation was recommended at 36 hours prior to solid texture, and the soluble protein and the phytic acid content on 48 fermentation were not significant.