Assessment of Japanese Awamori Spirits Using UV–VIS Spectroscopy

Awamori is a traditional distilled alcohol beverage unique to Okinawa, Japan. This study evaluated the potential of ultraviolet–visible (UV–VIS) spectroscopy in the assessment and differentiation of different Awamori samples. Thirty-one Awamori samples that could be classified differently based on attributes such as their distillation methods (atmospheric distillation and vacuum distillation), aging periods (0–18 years), batches (years 2017 and 2014), and distilleries of origin were investigated by UV–VIS spectroscopy and chromatographic analysis. Principal component analysis (PCA) of UV–VIS spectra showed that Awamori of atmospheric distillation and vacuum distillation could be clearly distinguished based on low and high PC1 scores, respectively; both young Awamori (aged less than 3 years) and Awamori from the 2017 batch exhibited low PC1 scores and high PC2 scores. Wavelength ranges with high loading values that correspond to the volatile compounds which have high correlations with PC scores, such as furfural, phenethyl alcohol, vanillin, and benzaldehyde, were observed in the UV–VIS spectral profiles. These volatile compounds with unique aroma characteristics can characterize Awamori attributes. Therefore, UV–VIS spectroscopy with the aid of chemometric analysis was demonstrated as a high potential technique for the rapid and low-cost evaluation and characterization of Awamori samples.