Digestibility and modulation of the infant gut microbiota of a spreadable prototype formulated with fermented Rochet beans

[EN] Childhood and adolescent overweight and obesity are growing problems today, not only causing immediate complications but also paving the way for adult-onset diseases such as type II diabetes and certain cardiovascular conditions. Among the dietary factors contributing to early overweight and obesity, the consumption of snacks stands out, as most of these products have low nutritional quality due to their high content of simple carbohydrates and saturated fats. In this context, this study proposes the development of new snack products based on legumes traditionally present in the Mediterranean diet as a healthy and environmentally sustainable alternative. Prior to this work, different snack bars were developed using nutritionally and functionally improve fava beans through fermentation with Pleurotus ostreatus. Solid-state fermentation with this fungus got to enhance protein digestibility. Thus, the objective of this work is to evaluate the nutritional quality, digestibility and impact over the microbiota of a spreadable prototype formulated with fermented and non-fermented Rochet beans, hazelnuts, dates, olive oil and cocoa. The proximal composition of the beans fermented with P. ostreatus and their spreadable product was determined. The degree of proteolysis and glycolysis was evaluated. Additionally, the non-digestible fraction used as the substrate for the colonic fermentation was characterized by the extraction of, bacterial DNA and through 16sRNA gene sequencing For the colonic fermentation study faecal samples of 10-year-old girls with overweight and normal-weight (control) were characterized, and they were evaluated for each case, changes produced at phylum level as the metabolic activity, production of short-chain fatty acids (GC-FID) and ammonium levels (quantitative kit). The results revealed that SSF with Pleurotus ostreatus not only enriched the nutritional profile of the beans improving their digestibility and increasing the protein content, but also induced changes in the girls’ microbiota. Specifically, there was a significant increase in SCFAs production, particularly butyric and propionic acids, in overweight participants. This effect was associated with shifts in the relative abundance of Firmicutes. All prototypes demonstrated the ability to reduce ammonium generation, a metabolite linked to epithelia damage, though responses varied among the girls. The complexity of the microbiota became evident when analysing microbial behaviour patterns, the same treatments produced distinct effects depending on each girl’s baseline microbiota. While ingredients like cocoa and hazelnuts in the spreadable formulations could modified these effects, the findings support the use of fermented Rochet beans as a functional ingredient.