Desenvolvimento e estabilidade de kefir de água saborizado

Abstract

The growing demand for functional beverages has encouraged the development of artisanal options with health-promoting properties. This study aimed to develop, optimize, and characterize a naturally carbonated water kefir flavored with grape juice, evaluating its physicochemical, microbiological stability, and sensory quality. The optimal fermentation conditions (F1) were determined using a Central Composite Rotational Design: 24 h at 30 °C with 6.5% brown sugar, ensuring a safe pH reduction. Grape juice was selected as the flavoring agent through sensory analysis, and a Mixture Design coupled with Desirability Function determined the ideal formulation as 50% kefir water, 46.4% grape juice, and 3.6% water, resulting in high overall acceptability. During 42 days of refrigerated storage (4 °C), progressive sugar consumption was observed, along with an increase in total phenolic compounds and antioxidant activity (FRAP), stability in ABTS activity, and a decline in DPPH. Lactic acid bacteria counts remained stable during storage, while acetic acid bacteria and yeast populations decreased. The pH (~3.30) and alcohol content (~1.86 °GL) remained constant. The developed kefir proved to be a promising alternative in the artisanal functional beverage market