Functional Fortification of Tibicos with Lemon Catnip (Nepeta cataria var. citriodora) Hydrolate: Fermentation Kinetics, Health-Promoting Potentials and Sensory Evaluation

The development of plant-based synbiotic beverages is gaining increasing attention as consumers seek sustainable, functional alternatives to dairy products. This preliminary study investigated the fortification of tibicos (water kefir) with lemon catnip (Nepeta cataria var. citriodora) hydrolate, an aromatic distillation byproduct rich in bioactive terpenoids. After 72 h-fermentation of tibicos, physicochemical, microbiological, health-promoting and sensory parameters were evaluated. Both control and fortified beverages exhibited typical fermentation kinetics, including a decrease in pH, reduction of soluble solids, and accumulation of organic acids. Lactic acid bacteria count remained stable, while yeast proliferation was slightly reduced in the hydrolate-fortified sample, consistent with the known yeast-sensitive nature of certain hydrolate-derived terpenoids. Importantly, hydrolate fortification significantly enhanced antioxidant capacity (DPPH: +34%; ABTS: +39%; RP: +38%). Enzyme-inhibitory activities also increased significantly in the hydrolate-fortified samples (α-Amylase and α-Glucosidase inhibition rates increased by 9% and 11%, respectively). ACE inhibition similarly increased from 32% to 44%, indicating an enhanced antihypertensive potential. HMG-CoA reductase inhibition increased from 31% to 42%, showing improved hypolipidemic activity. Sensory evaluation indicated improved sensory acceptability, imparting citrus–floral notes that balanced the acidic profile of tibicos. These findings highlight the potential of valorizing lemon catnip hydrolate as a functional fortifier in non-dairy synbiotic beverages.