ENRIQUECIMENTO DE KEFIR COM CULTURAS DE BACTÉRIAS AUTÓCTONES COM POTENCIAL PROBIÓTICO PRÉ-CARACTERIZADO

Introduction: Kefir is a fermented food rich in beneficial microorganisms, recognized for its probiotic potential and unique sensory characteristics. Its microbiota is composed of lactic acid bacteria, acetic acid bacteria, and yeasts, which interact during fermentation to form a viscous-textured product, slightly carbonated, with a characteristic aroma. The growing interest in functional foods has stimulated studies aimed at enriching kefir with specific strains to enhance its health benefits. In this context, the hypothesis of this work is that the addition of autochthonous bacteria previously characterized as potential probiotics could increase the functionality of kefir without compromising its original properties. Aims: The objective of this study was to evaluate the technical feasibility of enriching kefir with bacterial cultures isolated from the kefir itself, while maintaining the continuous use of the grains, and to verify the effects on physicochemical parameters and sensory characteristics. Materials and methods: Previously selected bacterial strains (7 and 8) were cultivated, adjusted to three concentrations (10⁸, 10⁶, and 10⁴ CFU/mL), and inoculated into kefir for fermentation, with control samples. The process was conducted for 30 hours, monitoring pH, density, and viscosity at defined intervals. At the end, color, odor, and grain weight were evaluated. Results: The pH showed a linear decrease during fermentation, regardless of the addition of strains. Density remained constant over 24 hours, and viscosity increased in the first 12 hours, stabilizing between 24 and 30 hours, with no significant differences between treatments. The main change was observed in the grain weight, influenced by both strain and concentration, with strain 7 at lower concentrations promoting greater weight gain. No visual or olfactory differences were detected among the samples. Final considerations: Enrichment of kefir with autochthonous strains potentially probiotic proved technically feasible, maintaining its original fermentative and sensory characteristics. The positive interaction observed in the grain weight increase suggests a possible synergy between the added strains, indicating potential for the development of differentiated functional kefirs. For future studies, it is recommended to include detailed microbiological analyses at the end of fermentation and controlled sensory tests.

Keywords: Kefir; Probiotic bacteria; Enrichment; Fermentation; Physical-chemical analyses.