Enhancing the sensory and nutritional properties of faba bean protein through fermentation with lactic acid bacteria...

Faba beans are rich in protein and fiber, but their consumption is limited by off-flavors, and antinutritional compounds. This study explored fermentations with lactic acid bacteria (LAB) and Bacillus spp. as a strategy to improve the sensory and nutritional qualities of faba bean protein concentrate (FPC). Fermentations were performed with the strains isolated from African fermented foods, including Limosilactobacillus fermentum NSB2, Lactiplantibacillus argentoratensis 12-27B and Bacillus velezensis G17, and with Bacillus subtilis Natto. Strain identification was performed using Oxford Nanopore whole-genome sequencing. Samples of fermented FPC (8 % w/v) were analyzed after 8 h, 24 h, and 48 h fermentation for volatile aroma compounds (VOCs), organic acids, free amino acids, γ-glutamyl peptides, and vicine-convicine. All strains effectively reduced aldehydes associated with beany off-flavors, such as hexanal. LAB, particularly L. fermentum NSB2, promoted alcohol formation, B. velezensis G17 produced the greatest amounts of diacetyl and acetoin, while B. subtilis Natto generated the largest amounts of esters. L. argentoratensis 12-27B was the most efficient producer of lactic acid, whereas B. velezensis G17 uniquely generated high levels of propionic acid. Bacillus spp. exhibited strong proteolytic activity during FPC fermentation, producing free amino acids, including essential ones. Several γ-glutamyl dipeptides were increased in fermentations, highest with Bacillus spp., suggesting potential kokumi enhancement. Notably, L. argentoratensis 12-27B and B. velezensis G17 significantly reduced vicine and convicine, the primary antinutritional compounds in faba beans. These findings highlight the potential of targeted fermentation to enhance the sensory quality and nutritional value of faba bean protein for plant-based food applications.