Optimization of an EPS-enriched gluten-free sorghum bread with improved technological properties and eubiotic potential: evidence from an in vitro colonic model

The growing demand for healthy and appealing gluten-free products has prompted research into alternative cereals like sorghum and targeted fermentation strategies. Hence, this study aimed at developing a gluten-free sorghum sourdough bread enriched in exopolysaccharides (EPS) and evaluating its technological, nutritional, and eubiotic potential using the MICODE in vitro colon model. Sorghum doughs were fermented with four selected lactic acid bacteria strains and in situ EPS production was optimized, with Leuconostoc pseudomesenteroides DSM20193 showing the highest yield (3.29 g/100 g). The resulting sourdough was incorporated into gluten-free corn-based bread formulations and compared with non-fermented control breads. EPS-enriched bread exhibited improved technological properties, including increased specific volume (up to 78%), reduced hardness (almost 50%), and enhanced sensory acceptability, moreover, fortification with fermented sorghum also determined a reduced starch hydrolysis index compared to corn breads. In vitro colonic fermentation demonstrated that EPS-enriched bread upheld microbiota eubiosis while promoting beneficial bacteria groups such as Bifidobacteriaceae, Lactobacillales, and second-generation probiotic like Faecalibacterium prausnitzii, ibidem reducing opportunistic groups including Clostridium cluster I and Enterobacteriaceae. Ecological indicators confirmed enhanced prebiotic activity and eubiotic effects compared to control breads without sorghum or with sorghum flour. Overall, the combination of sorghum and EPS-producing strains represents a promising strategy to develop functional gluten-free products with improved health-related properties.