The Japanese traditional pot-distilled spirit shochu has various tastes that are produced by variations in the manufacturing processes. In this study, an alcohol-stimulative taste was organoleptically evaluated using shochu samples, and the chemical components and proton nuclear magnetic resonance (1H NMR) spectra were measured. In some shochu samples, the alcohol-stimulative taste was weaker than that of the standard 15% (v/v) EtOH-H2O mixture, and the water-ethanol hydrogen-bonding structure was stronger compared to a water-ethanol solution. However, some shochu samples filtered with ion-exchange resin had a strong alcohol-stimulative taste comparable to that of the standard 15% (v/v) EtOH-H2O mixture, and the hydrogen-bonding structure was found to be similar to that of the water-ethanol solution. We also investigated the effect of MgCl2 on reducing the alcohol-stimulative taste, and it was observed most strongly with in shochu samples filtered with ion-exchange resin. The change in chemical shift values of the 1H NMR spectra was also the largest in ion-exchange resin filtered shochu samples. The sensory reduction in the alcohol-stimulative taste could be enhanced by the strengthening of the water-ethanol hydrogen-bonding structure. Shochu samples contained many components in larger quantities compared to vodkas. It was found that MgCl2 could reduce the alcohol-stimulative taste of shochu samples. Some salts, such as MgCl2, can be introduced into spirits through the water used to dilute the ethanol content before bottling the products. Our results indicated that some components, such as MgCl2, present in water used can reduce the alcohol-stimulative taste of different spirits produced worldwide.
Keywords: Alcohol-stimulative taste; Hydrogen bond; Nuclear magnetic resonance spectroscopy; Shochu; Spirit; Water; Water–ethanol.
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