Comparative effects of dairy and plant-based milk addition on physicochemical, functional, and sensory properties of coffee beverage

This study evaluated how the type of milk matrix (whole milk) and plant-based matrices (soy, almond, and coconut), together with their proportions with coffee (70:30, 50:50, and 30:70), influence the physicochemical, colorimetric, rheological, bioactive, and sensory properties of the beverages. As the amount of matrix increased, pH rose, titratable acidity decreased, and soluble solids (°Brix) increased, especially in whole milk, which reached 10.13 °Brix due to its higher lactose and total solids content. The values of L, C, h°, and WI also increased with greater matrix content; whole milk produced beverages with higher brightness and whiteness, whereas almond and coconut matrices produced darker beverages with more stable color. The plant-based matrices, especially almond and soy, showed antioxidant capacity values ranging from 13.77 to 14.22 mg TE/g and total phenolic content values reaching a maximum of 23.17 mg GAE/g in the 50:50 mixture with almond milk, reflecting matrix- and ratio-dependent responses . UHPLC analysis showed that chlorogenic acid (5-CQA) and caffeine (CAF) decreased as the proportion of milk matrix increased, while caffeic acid (CFA) was more frequently detected in formulations with higher matrix content. Regarding rheology, soy beverages exhibited the highest viscosities (up to 9.37 mPa·s) and a more pronounced pseudoplastic behavior as matrix concentration increased. Sensory acceptance was evaluated using a 9-point hedonic test with 60 untrained consumers. Significant differences in sensory scores were observed among formulations ( p < 0.05). Whole milk and almond formulations showed higher numerical scores when coffee was predominant (70:30) or balanced (50:50). In contrast, soy and coconut showed higher numerical scores in mixtures with higher matrix content (30:70), with coconut 30:70 reaching the highest overall acceptance 7.42. Pearson correlation analysis revealed that overall acceptance was primarily associated with flavor, while °Brix, titratable acidity, viscosity, and key bioactive compounds showed matrix-dependent associations with sensory perception. Overall, plant-based matrices elicited bioactive and sensory responses comparable to those of whole milk in specific formulations under the experimental conditions evaluated.