Development of a composite bread exploiting common bean (Phaseolus vulgaris L.) fermented flour with lactic acid bacteria

Legumes are sustainable and nutritionally valuable crops, yet their consumption is limited by antinutritional factors including lectins, phytic acid, and raffinose-family oligosaccharides (RFOs) impairing nutrient absorption and causing gastrointestinal discomfort. The study investigates the development of bread enriched with 25% fermented common bean (Phaseolus vulgaris L.) flour by exploiting lactic acid bacteria (LAB) fermentation from three different strains: Lentilactobacillus buchneri LBC01, Lacticaseibacillus rhamnosus LRH01, and Leuconostoc lactis LN01. Antioxidant activity and digestibility, but also technological aspects, including dough rheology, loaf volume, volatile organic compound profile, and shelf-life, were evaluated. Notably, LAB fermentation improved dough leavening and reduced staling within 24 h, enabling a higher incorporation of legume flour. Ln. lactis increased bread volume by 15% compared to Saccharomyces cerevisiae. RFOs were not detected in either the fermented flours or the resulting breads. The inclusion of fermented bean flour significantly enhanced antioxidant capacity, with radical scavenging activity nearly tenfold higher than that of the wheat bread. Analysis of volatile compounds showed that enriched bread exhibited the highest overall volatile content. 2-pentylfuran—associated with “beany” aroma—was elevated in breads containing fermented bean flour (FBF), while diacetyl and acetoin (contributing buttery and caramel notes) were most abundant in breads fermented with L. rhamnosus. Microbial proteolysis contributed to improved protein digestibility, and FBF breads also showed increased starch hydrolysis. Overall, LAB fermentation offers a viable approach for producing legume-enriched breads with superior nutritional quality, improved technological performance, and extended shelf life, while effectively mitigating common challenges associated with the use of legume-based ingredients.