Variations in the functional properties of soybean flour fermented with lactic acid bacteria

Abstract

The functional properties of soybean flour fermented with lactic acid (LAB)-consortium was evaluated. Soybean was processed into flour, fermented spontaneously and with LAB-consortium previously isolated from maize (Lactobacillus plantarum WCFS1+Lactobacillus rhamnosus GG, ATCC 53/03+Lactobacillus nantensis LP33+Lactobacillus fermentum CIP 102980+Lactobacillus reuteri DSM 20016) and sorghum (Pediococcus acidilactici DSM 20284+Lactobacillus fermentum CIP 102980+Lactobacillus brevis ATCC 14869+Lactobacillus nantensis LP33+Lactobacillus plantarum WCFS1) to evaluate their effects on the functional properties of the flour at 12 h intervals using standard techniques. The result shows gradual decrease in bulk density with increasing fermentation period ranging from 0.74 0.03 g/mL to 0.72 0.03 g/mL (natural), from 0.74 0.03 g/mL to 0.70 0.02 g/mL (LAB-consortium from maize) and from 0.74 0.03 g/mL to 0.70 0.02 g/mL (LAB-consortium from sorghum) fermentation. The swelling capacity decreased from 0.77 0.03 g/mL to 0.64 0.01 g/mL, from 0.77 0.03 g/mL to 0.59 0.01 g/mL and from 0.77 0.03 g/mL to 0.61 0.03 g/mL in natural, LAB-consortium from maize and sorghum fermentations respectively. Water holding capacity decreased from 2.4 0.03 mL/g to 1.9 0.03 mL/g, from 2.4 0.03 mL/g to 2.0 0.03 mL/g and from 2.4 0.03 mL/g to 1.9 0.03 mL/g in natural, LAB-consortium from maize and sorghum fermentation respectively. Oil holding capacity increased significantly (p<0.05) with increasing fermentation time, ranging from 8.92 0.02 mL/g to 9.30 0.03 mL/g (natural), 8.92 0.01 mL/g to 9.63 0.03 mL/g (LAB-consortium from maize) and from 8.92 0.03 mL/g to 9.69 0.03 mL/g (LAB-consortium from sorghum) fermentations. The least gelation concentration ranged from 3.0% (unfermented) to 6.0% (other fermentation products). Emulsion capacity (EC) increased from 35.88 3.12% to 44.33 1.33%, from 35.88 3.12% to 46.83 3.18% and from 35.88 3.12 % to 45.99 2.21% in natural, LAB-consortium from maize and sorghum fermentations respectively. This suggests the potentials of LAB-consortia fermentation in improving nutritional and functional properties of soybean flour.