Abstract
The development of fermented plant-based beverages requires careful selection of microbial starters and substrates to optimize nutritional quality, bioactive compound profiles, and functional properties. This phd thesis explores how microbial-plants interactions influence the nutritional quality, functional property, and sensory characteristics of dairy alternatives. Firstly, water kefir-derived microbial ecosystems, including Leuconostoc mesenteroides, Lacticaseibacillus paracasei, Lactiplantibacillus plantarum, and Pichia bruneiensis, were successfully applied to multi-plant beverage formulations. Fermentation with Lc. paracasei alone or ternary lactic acid bacteria (LAB) cultures achieved superior microbial growth, strong acidification, enhanced proteolysis, and significant release of phenolic compounds including chlorogenic acid, epicatechin, catechin, and rutin. The ternary LAB culture uniquely degraded phytic acid, while P. bruneiensis improved beverage stability by minimizing syneresis. Secondly, complementary investigations using chestnut-persimmon and quinoa flours fermented with freeze-dried strain ( Lacticaseibacillus casei Lyofast BGP 93 provided by SACCO S.r.l. ) demonstrated high LAB viability (>8 log CFU/mL) and stable acidification. Matrix-dependent biochemical shifts were observed: chestnut-persimmon beverages retained higher polyphenol stability and balanced aroma profiles with aldehyde suppression, while quinoa beverages maintained diversified flavonoid profiles and accumulated lipid-derived volatile compounds. Both formulations showed reduced antinutritional factors and improved protein digestibility following fermentation. In the third study, an innovative approach using synthetic co-cultures within self-generated cellulose scaffolds (SC-CS) demonstrated that L. plantarum, Levilactobacillus brevis, and Schizosaccharomyces pombe could be stably co-cultured with Komagataeibacter xylinus, forming mixed-species biofilms. These SC-CS preserved microbial composition across multiple fermentation cycles and influenced phenolic and volatile compound profiles through microbial interactions and cross-feeding mechanisms. Collectively, these findings establish that strategic pairing of specific microbial starters with diverse plant substrates enables the creation of functional, nutritionally enhanced, and sustainable plant-based beverage alternatives with tailored sensory and health-promoting properties.