Kikunae Ikeda

A physical chemist known for inventing Ajinomoto. Born in Kyoto on September 8, 1860, he graduated from the Department of Chemistry at the Faculty of Science, Tokyo Imperial University in 1889 (Meiji 22), became a professor there in 1901 (Meiji 34), and retired in 1923 (Taisho 12). In 1899, while still an assistant professor, he studied under F. W. Ostwald at the University of Leipzig in Germany, which was the mecca of physical chemistry at the time. On his way back to London, he stayed there for a while, and his interactions with Natsume Soseki are well known. Soseki, who was mentally and physically unstable at the time, respected Ikeda's character, erudition, and insight, and found great comfort in him. Ikeda participated in the founding of the Institute of Physical and Chemical Research in 1917 (Taisho 6), and later became a senior researcher there. After retiring from the university, he led an unusual life of research, having a laboratory in Germany for five years, and also setting up a laboratory in his home where he studied aromas and odors with five other researchers until the year of his death. During his tenure as a professor at Tokyo Imperial University, he had the idea that in addition to the four tastes of sweetness, sourness, bitterness, and saltiness, there must be an "umami" taste. He encouraged his janitors to extract "umami" from large quantities of kelp, and eventually discovered that the main component was monosodium glutamate. This is what we know as "Ajinomoto" today. During his studies in Germany, he was influenced by Ostwald's energy monism, but was not devoted to it. He died in Tokyo on May 3, 1936.

[Tsurutaro Nakagawa]

"Lectures by Professor Kikunae Ikeda" by Hayashi Taro (published in Chemistry History Research, No. 13, 1980, Uchida Rokakuho Shinsha)

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

「味の素」の発明などで知られる物理化学者。元治(げんじ)元年9月8日、京都に生まれ、1889年（明治22）東京帝国大学理科大学化学科を卒業、1901年（明治34）同教授、1923年（大正12）退職した。助教授在職中の1899年に、当時の物理化学のメッカであったドイツのライプツィヒ大学のF・W・オストワルトのもとに留学。帰途しばらく滞在したロンドンでの夏目漱石(そうせき)との交流はよく知られている。心身ともに不安定であった当時の漱石は、池田の品性、博識、見識に敬意を覚えつつ大いに慰められた。池田は1917年（大正6）理化学研究所創立に参画、のち主任研究員にもなった。大学退職後はドイツに5年間研究室をもったり、自宅に実験室を設けて5名の研究者と死の年まで香気、臭気の研究をするなど、異色の研究生活を送った。東京帝国大学教授在職中、物質の味には甘味、酸味、苦味、塩から味の四味のほかに、「うま味」があるはずとの着想をもち、用務員を督励して大量のコンブから「うま味」を抽出、ついにその成分の本体がグルタミン酸ナトリウムであることをつきとめた。これが今日の「味の素」である。なお彼はドイツ留学中、オストワルトのエネルギー一元論の影響は受けたが、傾倒することはなかった。昭和11年5月3日東京にて死去した。

［中川鶴太郎］

『林太郎著『池田菊苗先生の講義』（『化学史研究』第13号所収・1980・内田老鶴圃新社）』

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