Abstract

Poster Presentations

Day 1, May 15（Mon.）　　Room P (Foyer, Room 1004-1007)

1P-27　　PDF

Determination of carbon stable isotope ratios of free amino acids in commercial soy sauce samples

(Akita Pref. Univ.)
^oKohei Sasaki

Soy sauce is seasoning made from soybean and wheat. Soy sauce can have amino acid seasonings added, but soy sauce with seasonings used without mentioning them on the label is considered problematic in globally. Therefore, identification of soy sauce raw materials is becoming increasingly important. In 2004, liquid chromatography and isotope ratio mass spectrometry (LC-IRMS) were developed, which is mainly used as an approach to ensure reliability and traceability of agricultural products. A method for measuring the (δ¹³C) composition of amino acids using LC-IRMS was established in 2006.
In this study, the δ¹³C of free amino acids for each soy sauce composition was analyzed by LC-IRMS for the first time. As the results, the average δ¹³C of glutamic acid in pure soy sauce was -25.96 ± 2.67‰. Soy sauce with amino acid seasoning was -20.29 ± 4.41‰. Soy sauce with amino acid seasoning was +5.26‰ heavier than pure soy sauce. Therefore, soy sauce with seasoning is thought to contain amino acid seasonings of C4 plant origin, such as corn. This method is considered to be an effective method to detect the addition of amino acid seasonings in soy sauce.