π–π (pi-pi) Stacking Interactions

π–π (pi-pi) Stacking Interactions are non-covalent chemical interactions that occur between aromatic rings, frequently observed in the complex chemical matrices of certain beverages.

In the context of dealcoholization and NoLo beverage manufacturing, these interactions play a crucial role in flavor retention and mitigating organoleptic-yield-loss. Specifically, certain volatile aroma compounds—such as β-phenylethyl alcohol (which imparts a rose aroma) and 2-phenylethanol—exhibit high retention rates during the extraction of ethanol.

This retention is largely due to their low volatility, high solubility in water, and their ability to form π–π stacking interactions with polyphenols present in the liquid. Because red wines possess a significantly higher polyphenolic fraction than white wines, these non-covalent bonds allow red wines to “hold onto” their complex flavor molecules more effectively during thermal or membrane dealcoholization. Consequently, white wines are far more susceptible to massive losses of ketones and lactones (up to 92% degradation) compared to their red counterparts.