Sourdough fermentation and red lentil protein enrichment as sustainable valorization of pasta by-products to make new pasta

This study explored the potential of using pasta by-products-based sourdough, with or without red lentil protein isolate (RLPI) enrichment, for pasta making. <i>Fructilactobacillus sanfranciscensis</i> A1, <i>Lacticaseibacillus rhamnosus</i> Fc3-6, and <i>Lacticaseibacillus casei</i> Fc1-13 were used as sourdough starters, while various fermentation times were screened during backslopping to achieve the target pH (approximately 4.6). Twenty percent of newly formulated sourdoughs were mixed with semolina flour for pasta making and evaluated for technological, textural, and biochemical properties. Confocal laser scanning microscopy showed that the new pasta had a similar microstructure compared to the traditional semolina counterpart. RLPI-enriched sourdough pasta showed superior amino acid profiles and optimal protein and starch digestibility. The enrichment of RLPI ensured a unique phenolic compound profile (catechin, salicylic acid, naringenin, and kaempferol), potentially enhancing the antioxidant value of new pasta. Although a slightly longer optimal cooking time, RLPI-enriched sourdough pasta showed favorable sensory attributes, including improved color perception, while preserving textural properties. Sourdough fermentation allowed RLPI to enrich pasta with recycled pasta by-products, promoting the sustainability of the food system.