Naturally Caffeinated Functional Beverage Based on Grape Juice and Cryoconcentrated Yerba Mate Extract

This study investigates the impact of cryoconcentration as a nonthermal enrichment strategy on the chemical, antioxidant, mineral, and sensory properties of mixed beverages composed of grape juice (SU) and yerba mate extract. Aqueous yerba mate extract was subjected to two successive cryoconcentration stages, and the enriched fraction (EMC1.5) was blended with SU at different proportions. The resulting beverages were comprehensively characterized in terms of physicochemical parameters, instrumental color, mineral composition, bioactive compounds, antioxidant activity, methylxanthine content (caffeine and theobromine), and sensory attributes, complemented by multivariate analysis using principal component analysis (PCA). Cryoconcentration significantly increased the concentration of phenolic compounds and enhanced antioxidant capacity in formulations with higher EMC1.5 proportions, highlighting the effectiveness of this low-temperature process in preserving and concentrating bioactive constituents. In contrast, increasing the SU proportion promoted higher anthocyanin and total polyphenol levels and positively influenced sensory balance, reflecting the contribution of grape-derived pigments and sugars. Antioxidant activity varied according to the analytical method applied, suggesting differences in phenolic composition and radical-scavenging mechanisms between the matrices. Methylxanthine contents were strongly associated with EMC1.5, confirming yerba mate as the primary source of natural caffeine and theobromine. PCA indicated a separation trend among formulations according to their composition, suggesting that the SU/EMC1.5 ratio was associated with differences in chemical profile, antioxidant activity, mineral composition, and sensory perception. Overall, the results indicate that cryoconcentration and formulation proportion influence the physicochemical and antioxidant characteristics of mixed plant-based beverages, contributing to the understanding of nonthermal processing effects in food systems containing bioactive compounds.