Development of Smoothies Fermented with Kombucha Microorganisms: Sensory Characteristics, Functional Properties, and Microbiological Aspects

Smoothies and kombucha are beverages appreciated by contemporary consumers due to their appealing flavor, convenience, and perceived health benefits. This study aimed to develop fruit- and white tea-based smoothies with high sensory and functional quality, and to evaluate the effects of fermentation with kombucha microorganisms. The smoothie base (70%) was composed of 60% strawberry pulp and 40% cryoconcentrated apple juice. Ten formulations were designed using a centroid simplex approach and subjected to sensory analysis. The two most accepted by consumers (E5: 15% blackberry pulp and 15% white tea; E10: 5% blackberry pulp and 5% acerola pulp, and 20% white tea) were fermented for 10, 15, and 20 h. The formulations were evaluated through sensory analysis. Fermentation led to significant (p < 0.05) reductions in glucose, fructose, and caffeine contents, while significantly (p < 0.05) increasing acidity, total phenolic content, ascorbic acid levels, and color intensity. Moreover, the fermented smoothie exhibited higher α-glucosidase inhibitory potential. One fermented smoothie (E5 fermented for 15 h) showed desirable sensory and functional properties. Therefore, this study demonstrates the successful development of smoothies, fermented or non-fermented with kombucha microorganisms, characterized by strong functional attributes and high sensory acceptance.