Rehydration Beverages Made from Quercus sideroxyla Infusion, Probiotics, and Prebiotics: Antioxidant and Anti-Inflammatory Potential

High rehydration beverage consumption represents a significant opportunity for the integration of biotic products that offer the potential to improve body composition and intestinal health. <i>Quercus sideroxyla</i> (IQS) infusions contain polyphenolic compounds with antioxidant and anti-inflammatory properties, and in combination with probiotic strains and prebiotic materials, they offer a promising alternative for generating designer beverages for physically active people. These beverages were formulated using a combination of IQS, agave fructooligosaccharides (FOS), microencapsulated probiotics of <i>Akkermansia muciniphila</i> and <i>Bifidobacterium longum</i>, electrolytes, and glucose. Stable microencapsulated probiotics were obtained by spray drying, using agave gums (PD > 10) and gum arabic as wall materials. The beverage formulations were generated with different percentages of FOS (A:1.6%, B:1.2%, and C:0.8%). The phenolic profile of the beverages was determined by LC-MS/MS, indicating a difference in the concentration of compounds, highlighting changes associated with the addition of FOS compared with IQS. Sensory analyses indicate a preference for the beverage with the highest FOS concentration. The antioxidant potential of the formulations, determined by ABTS, DPPH, and ORAC, showed no differences between the drinks; however, analyses indicate a positive correlation with quinic acid, t-cinnamic acid, quercetin 3-O-glucoside, and total phenolic content, suggesting a synergistic effect. The drinks with higher FOS content exhibited a higher anti-inflammatory potential (EMA). Therefore, it can be concluded that a rehydrating drink with a higher FOS content offers a prebiotic effect with potential anti-inflammatory activity and, according to the panelists, is a suitable drink for evaluating its effects on body composition and intestinal health in people who have recently started physical activity.