Effects of distillation process on antioxidant activity of Japanese traditional spirits rice-shochu

In this study we investigated the effects of the distillation process on the antioxidant activity of Japanese traditional spirits “riceshochu”, particularly focusing on DPPH (1, 1-diphenyl-2-picrylhydrazyl) radical scavenging activity and lipid peroxidation inhibitory activity. Using polished rice, white-koji (Aspergillus kawachii) and S-2 yeast (Saccharomyces cerevisiae), we prepared rice-shochu using both vacuumand atmospheric-distillation processes. The lipid peroxidation inhibitory activity of vacuum-distilled shochu was 8.2 (± 0.4) μM BHT eq., whereas that of atmospheric-distilled shochu was 12.3 (±0.7) μM BHT eq., representing a significant difference (p<0.01). However, DPPH radical scavenging activity of vacuum-distilled shochu was 3.9 (± 1.2) μM Trolox eq., whereas that of atmospheric-distilled shochu was 3.4 (±0.1) μM Trolox eq., representing no significant difference (p<0.01). Furthermore, we analyzed the absorption spectra of both types of shochu and observed a common absorption maximum at 260 nm. Notably, the absorption values of the atmospheric-distilled shochu were higher than that of vacuum-distilled shochu. In addition, HPLC analysis of potential components with absorption maximum at 260 nm identified two peaks in the atmospheric-distilled shochu that were not detected in the vacuum-distilled shochu.