Tracing Raw Materials of Commercially-supplied Mirin by Carbon Stable Isotope Analysis

In this study, we determined the carbon stable isotope ratios of the extract (δ13CEx) and alcohol (δ13CAlc) in commercially-supplied Mirin in order to confirm them as a potential index for verifying the raw-material origins. The δ13CAlc values of the Mirin, to which brewing alcohol was added (−14.6±4.0‰), are significantly higher than that of the Mirin, to which Shochu was added (−26.0±1.7‰). The δ13CEx values of the Mirin are significantly higher by sugar addition (+sugar; −17.1±3.3‰, −sugar; −26.1±1.0‰). Old-style Mirin, which was made from rice, koji, and Shochu shows lower δ13CAlc and δ13CEx values (δ13CAlc; −25.8±1.1‰, δ13CEx; −26.6±0.9‰) than those of new-style Mirin, which includes brewing alcohol and sugar as raw materials (δ13CAlc; −16.3±0.8‰, δ13CEx; −19.8±0.7‰). Mirin-like seasonings (fermentation seasoning and Mirin-type seasoning) and Akumochizake used like Mirin were also analyzed; their δ13CAlc and δ13CEx showed higher values upon the addition of brewing alcohol and sugar, respectively. These results suggest that the δ13CAlc and δ13CEx values in commercially supplied Mirin are useful for the confirmation of sugar, brewing alcohol, and Shochu addition as raw-material origins.