Characterization of Flavor Compounds from Hops ( <i>Humulus lupulus</i> L.) Variety Polaris Contributing to the Cooling Sensation: Mechanistic Insight Involving Three Flavor Compounds

A variety of hops (<i>Humulus lupulus</i> L.), also known as Polaris, imparts a unique minty flavor to beer. This study focused on the minty cooling sensations (initial and after tastes) in Polaris beer. Using selectable one-dimensional or two-dimensional gas chromatography-olfactometry/mass spectrometry analysis, 1,8-cineole, 2-acetylpyrrole, and methyl <i>trans</i>-geranate were identified as candidate compounds. Their effect on beer flavor, including the cooling sensation, was assessed using sensory techniques. The sensory tests indicated that the combined effect of all three compounds could contribute to the cooling sensation in Polaris beer, and that methyl <i>trans</i>-geranate was found to be more effective in inducing the aftertaste than the initial taste. In conclusion, a new mechanism involving these three flavor compounds is proposed for the development of a cooling sensation. The characteristics of 1,8-cineole, 2-acetylpyrrole, and methyl <i>trans</i>-geranate in different hop varieties are also discussed.