Development and characterization of seriguela (Spondias purpurea) water kefir: metagenomic insights and functional potential of a spray-dried probiotic powder.

Water kefir is a fermented probiotic beverage suitable for those with lactose intolerance, dairy allergies, or vegan diets. Adding fruits during fermentation can modulate microbial dynamics, sensory attributes, and biochemical composition, thereby enhancing functional properties. In this context, Spondias purpurea (seriguela), a bioactive-rich fruit native to the Americas, represents a promising yet underexplored substrate for the development of functional beverages. Therefore, this study investigated the composition of seriguela and its application in water kefir production, followed by physicochemical and metagenomic characterization and the evaluation of spray-dried formulations. Seriguela fruits exhibited an acidic pH (3.63), the presence of coumarins, steroids, and tannins, and remarkable antioxidant activity. Seriguela-flavored kefir maintained microbial levels comparable to those of traditional kefir (7.1 and 6.8 log CFU/mL for bacteria and yeasts, respectively), promoting a predominance of Komagataeibacter saccharivorans, Acetobacter aceti, A. lovaniensis, Liquorilactobacillus mali, Clostridium pasteurianum, and yeasts from the Saccharomyces genus. This change in the microbiota of seriguela-flavored kefir indicates a more homogeneous fermentation with pronounced acetic characteristics and probiotic potential. Furthermore, the spray-dried kefir demonstrated good physical properties, remarkable resistance under simulated gastrointestinal conditions, and moderate stability during refrigerated storage throughout 30 days (75.7% and 82.9% of survival for bacteria and yeasts, respectively, enumerated on De Man, Rogosa & Sharpe agar and potato dextrose agar), highlighting its potential as a stable probiotic product. Overall, these results demonstrate the suitability of seriguela as a functional ingredient in water kefir and confirm spray-drying as a viable strategy for producing stable fermented powders with potential health-promoting properties.