Cholesterol-lowering and radical-scavenging potential of fermented black kale (Brassica oleracea var. acephala): From pilot-scale production to an in vivo study.

Vegetables are rich in bioactive compounds, including fibers and minerals, providing a conspicuous contribution to achieving health benefits. In this study, black kale (Brassica oleracea var. acephala, BK) was fermented using Saccharomyces cerevisiae LI180-7 strain at pilot scale, producing a safe and consumable product featured by improved organic acid concentration, phenols, and antioxidant activity. Thus, a pilot dietary intervention was carried out based on 26 volunteers consuming 100 g of fermented-BK 3 times weekly for one month. Fecal and blood samples were collected before (T0) and after (T1) the intervention to analyze gut microbiota, fecal metabolome, and hematochemical parameters. While overall taxonomic differences were not significant for the relative abundance, an increased prevalence of specific health-promoting genera was found at T1. Among fecal short-chain fatty acids, the decrease of acetate and the increase of butyrate and propionate concentrations suggested an enhancement in microbial cross-feeding associated with a bifidogenic effect. Higher levels of branched-chain fatty acids were also found due to the greater amino acid bioavailability featuring fermented BK. Noteworthy, a significant reduction in serum cholesterol was observed in normolipidemic individuals, and this was further confirmed in a small hypercholesterolemic subgroup. Therefore, despite the limited microbial taxonomic changes, this study highlights the potential of a fermented niche vegetable in gut microbiota modulation and health according to promising beneficial outcomes.