Abstract
In the context of increased waste generation and the need for sustainable solutions, several approaches have been investigated as pre-treatment of food waste to improve the nutritional, functional, and technological properties before to re-inclusion in food production. In this perspective, this thesis revealed the latest insights into the potential of tailored fermentation to recycle bread waste, pasta regrind, and brewer’s spent grain. Within the bread waste context, bread waste-based sourdoughs made by combining protease and Lactiplantibacillus plantarum B2 alone or in combination with Saccharomyces cerevisiae E3 were used, at different percentages, for bread making. Although a slightly acidic pH and a low leavening power, due to the denatured proteins and gelatinized starch in the bread waste, the breads had textural attributes, smell, acidic taste, and overall acceptability that were better sensorially perceived compared to the control. From the standpoint of pasta regrind recycling, pasta waste-based sourdough, with or without red lentil protein isolate (RLPI) enrichment, were used for pasta making. Twenty percent of newly formulated sourdoughs were mixed with semolina flour for pasta making and evaluated for technological, textural, and biochemical properties. 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 by-products, promoting the sustainability of the food system. Finally, the starter-assisted fermentation of brewer's spent grain (BSG) using Fructobacillus fructosus PL22 and Wickerhamomyces anomalus GY1 generated the highest number of unique peptides, with only one previously identified as antioxidant peptide, found in BSG fermented with F. fructosus. The metabolic shifts among the starters were associated with enhanced antifungal and antioxidant properties, as well as improved skin protection, indicated by increased proliferation of human keratinocytes, superior wound healing, and elevated filaggrin (FLG) gene expression. Overall, this thesis shed light on the power of fermentation to transform agricultural by-products into valuable resources, addressing waste management and enhancing health benefits.