– Faculty of Systems Science and Technology, Department of Management Systems Engineering –
Associate Professor Hiroto Kawashima of the Department of Management Systems Engineering, Faculty of Systems Science and Technology, along with Momoka Suto, who graduated from our graduate school in 2020, published a research paper titled “Discrimination for Sake Brewing Methods by Compound Specific Isotope Analysis and Formation Mechanism of Organic Acids in Sake” in the international academic journal Food Chemistry on February 1, 2022.
Ms. Suto is currently employed at the Japan Analytical Center, a public interest incorporated foundation.
Journal: Food Chemistry
Paper Title: Discrimination for Sake Brewing Methods by Compound Specific Isotope Analysis and Formation Mechanism of Organic Acids in Sake
Authors: Momoka Suto, Hiroto Kawashima
Website: https://doi.org/10.1016/j.foodchem.2022.132295
Comment from Momoka Suto:
This time, I reported on the discrimination of sake brewing methods in the international food science journal Food Chemistry. In this research, I established the analytical method during my first year of the master’s program (reported in Analytical and Bioanalytical Chemistry), and then collected and analyzed 49 types of sake mainly from Akita Prefecture using this method during my second year. I wrote the paper gradually while working after graduation, using weekends and available time to complete it. Writing while working was somewhat challenging, but I am relieved that it was eventually accepted.
I am grateful to Professor Kawashima, research assistant Raku Fujishima, and other members of the laboratory for their support. I also hope this research serves as a way to give back to Akita Prefecture, which is famous for its sake.
Comment from Associate Professor Hiroto Kawashima (Department of Management Systems Engineering, Faculty of Systems Science and Technology):
Organic acids in sake play an important role by contributing to flavor, color, aroma, and controlling microbial activity. In recent years, there has been an increase in distinctive sake products made by changing the quantity and balance of organic acids using yeasts that produce large amounts of malic acid or koji mold that produces large amounts of citric acid.
The main organic acid in sake is lactic acid, which inhibits the growth of unwanted yeast. There are two methods for producing the sake starter mash (shubo): the kimoto method, which uses lactic acid generated by lactic acid bacteria, and the sokujo method, which adds brewing lactic acid artificially to prevent unwanted yeast growth. Because the sokujo method greatly reduces labor, it has become the most common production method in recent years.
In this study, using liquid chromatography/isotope ratio mass spectrometry (LC/IRMS), we performed compound-specific analysis of organic acids in 49 sake samples mainly from Akita Prefecture, and established a method to discriminate between kimoto and sokujo brewing methods. Our method achieved an 87.8% accuracy in distinguishing these two methods. Furthermore, we elucidated the formation mechanisms of organic acids from the perspective of stable isotopes. This study represents the world’s first report of these findings.
Momoka Suto, who conducted this research, has published eight papers in international journals (five as first author). She has produced an impressive amount of research achievements for a master’s student and was awarded “Outstanding Graduate Student Research.” Her perseverance and steady progress are invaluable qualities for research, and I believe this is her greatest strength. She continues her research activities at the Japan Analytical Center where she works, and I hope she will advance her research further. I also hope that current students at our university will be inspired by the achievements of alumni like her.
This research was supported by KAKENHI Grant-in-Aid for Scientific Research (A) and our university president’s project “Industry-Academia Collaboration Promotion Project.” We also deeply appreciate the cooperation of Mr. Furuki and Mr. Baisho of Akita Shurui Seizo Co., Ltd. (Takashimizu), as well as various domestic sake manufacturers, who provided samples and valuable information.
Additionally, the Kawashima Laboratory has published two papers related to sake: one proposing criteria to identify the addition of brewing alcohol in sake, and another establishing an analytical method for carbon stable isotope ratios of organic acids in sake (as listed below).
★Momoka Suto During Her Studies★
Awarded for Outstanding Research Achievements!
