How wine blending influences their biological activity: A case study of Cabernet Sauvignon and Merlot coupages

Blending different grape varieties or wines is essential in winemaking to enhance sensory attributes, but could potentially impact the biological activity of the final product. This study investigates the polyphenolic profile and bioactivities of monovarietal wines Cabernet Sauvignon (CS) and Merlot (M), their blends in three different ratios (CS1M1, CS3M1, CS1M3), as well as one commercial coupage (CSM). Enzyme inhibition (α-amylase, α-glucosidase, lipase, tyrosinase), antioxidant properties (inhibition of AAPH-induced ROS generation in U937 cells and lipid peroxidation), and anti-inflammatory properties (inhibition of PGE₂ production in U937 cells) were assessed. Results revealed quantitative differences in seventeen polyphenols, with dominant gallic acid (41.1-69.7 mg/L) and catechin (15.3-24.5 mg/L), but no straightforward correlation with bioactivity. All samples showed considerable bioactivity, but the potency varied significantly, indicating that the bioactivity of each blend is unique and cannot be reliably predicted. Further research is suggested to identify an optimal polyphenolic profile for maximum positive effects.