Use of Selected Lactic Acid Bacteria for the Fermentation of Legume-Based Water Extracts

In this study, the effect of selected Lactobacillus acidophilus ATCC 4356, Limosilactobacillus fermentum DSM 20052, and Lacticaseibacillus paracasei subsp. paracasei DSM 20312 strains on the sensory characteristics, and protein and amino acid content of fermented water extracts derived from lupin, pea, and bean grains is reported. Even though all strains were able to grow over 7 log cfu mL^-1 and to decrease pH in the range of -0.52 to -1.25 within 24 h, the release of an unpleasant ferric-sulfurous off-odor from the fermented bean water extract prohibited further characterization. Lupin and pea grain-based beverages underwent an in-depth sensory evaluation using a simplified check-all-that-apply (CATA) method, finding new and appreciable sensory notes such as cooked ham, almonds, and sandalwood. Fermented lupin water extract showed higher total protein content (on average, 0.93 mg mL^-1) in comparison to that of pea grains (on average, 0.08 mg mL^-1), and a free amino acid content (on average, 3.9 mg mL^-1) close to that of cow milk. The concentrations of these nutrients decreased during refrigerated storage, when the lactic acid bacteria load was always higher than 7 log cfu mL^-1. The results of this study indicated that lactic fermentation improves the sensory characteristics of these innovative legume-based beverages, which sustained high loads of viable lactobacilli up to the end of cold storage.