Fermented beverages from pigeon pea (Cajanus cajan) and rice bean (Vigna umbellata Thumb. Ohwi and Ohashi)

Results of preliminary studies on pH and percent titratable acidity (expressed as percent lactic acid) determination showed that some lactic cultures such as Lactobacillus plantarum, L. casei, L. delbrueckii, Streptococcus cremoris, and L. bulgaricus produced higher lactic acid and gave low pH values than L. acidophilus, Streptococcus lactis, S. thermophilus, and P. cerevisiae in legume milk prepared from germinated seeds. Three fermented beverages were produced such as acidophilus-type, delbrueckii-type and drink legume yoghurt-type fermented beverages inoculated with L. acidophilus, L. delbrueckii and L. bulgaris and S. thermophilus, respectively. Lactic cultures preferred the legume milk prepared from germinated seeds than soaked seeds resulting in higher acid produced and lower pH values. The drink yoghurt-type beverages gave the lowest pH (3.61 to 4.68) and higher acidity (0.20 to 0.60%) among the three products. Protein content generally increased for fermented legume beverages prepared from 24 h germinated seeds but decreased in beverages from seeds germinated for 48 h. The increase was accompanied by an increase in acidity. The fermented beverages had lower starch content, total sugars, and total solids. Germination and fermentation resulted in lowering of total sugars, starch, and proteins. Stachyose, raffinose and sucrose constituted the main bulk of the sugars in legumes. Germination and fermentation provide suitable means to reduce the flatulence factor in legumes. Results of HPLC analysis showed degradation of stachyose and raffinose, increase in sucrose content and the presence of trace amounts of glucose, galactose, and fructose. Sensory evaluation of the fermented beverages showed no significant differences in the attributes tested between products prepared from 24 h and 48 h germinated seeds. Comparison with skimmilk-based fermented beverages (control) showed no significant differences in general flavor, acid taste and sweetness. The fermented beverages seemed inferior to the control in terms of color, aroma and consistency