Stable Isotope Analysis for Tracing the Geographical Origin of Processed Eel

We determined the stable carbon, nitrogen and oxygen isotopic compositions (δ13C, δ15N and δ18O) of processed eels (Shirayaki and Kabayaki) in order to demonstrate the effect of the processing process on their stable isotopic compositions. There were no significant change in the δ13C, δ15N and δ18O values between eels and processed eels. We examined processed eels from Japan (n = 84), China (n = 30), and Taiwan (n = 10) to trace their geographical origin. The Japanese eels had lower δ18O values (+ 8.9 ± 1.4‰) than the Chinese (+ 12.9 ± 1.8‰) and Taiwanese eels (+ 13.1 ± 2.2‰). A principal component analysis using carbon, nitrogen and oxygen isotopic compositions of Japanese, Taiwanese and Chinese processed eels showed a difference tendency. Thus, stable carbon, nitrogen and oxygen isotope analyses would probably be a useful tool for tracing the geographical origin of processed eels.