Comparative Effects of Bacterial and Yeast Fermentation on Nutritional & Bioactive Properties in Chickpea Protein...

Microbial fermentation of legume proteins and legume-based ingredients is increasingly recognized as an effective strategy for developing innovative food products with improved nutritional and functional properties. Accordingly, this study aimed to comparatively evaluate the effects of fermenting chickpea protein isolate (CPI) using the lactic acid bacterium Lactobacillus helveticus, the bacterium Bacillus subtilis, and the yeast Kluyveromyces marxianus on its antioxidant capacity, nutritional quality, and protein molecular weight distribution. Microbial growth occurred predominantly within the first 24 h and differed significantly among microorganisms, with B. subtilis (2.7 ± 0.1 log CFU/mL increase) showing the highest and L. helveticus (0.9 ± 0.1 log CFU/mL increase) showing the lowest increase. Despite the reduction in certain amino acids, fermentation increased the essential-to-total amino acid ratio in all samples, with the greatest enhancement observed in Bacillus-fermented products. While antioxidant activity markedly enhanced following B. subtilis fermentation in DPPH, ABTS, and CUPRAC assays, K. marxianus and L. helveticus did not induce significant changes compared to the control sample, with total phenolic content remaining statistically unchanged across all groups. Fermentation also reduced phytic acid content from 44.5 μg/100 mL in the control sample to 38.3 μg/100 mL (14%) with B. subtilis, 30.5 μg/100 mL (31%) with K. marxianus, and most markedly to 13.3 μg/100 mL (70%) with L. helveticus, while condensed tannins exhibited only minor reductions, decreasing from 3.20 to 2.68 mg catechin/100 mL.