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Kyoto Univ. researcher seeks firms to help bring healthy moth feces tea to market

Chongshicha, a tea made from insect feces which looks and tastes rather like black tea, is seen in this image provided by Takeshi Maruoka.

KYOTO -- A postgraduate student at Kyoto University wants to make it commonplace for us to warm our cups with chongshicha -- literally insect feces tea -- a brew that uses excrement from leaf-chomping moth larvae.

    Because the flavor and aroma of the tea varies depending on the leaves and the insects producing the droppings, Takeshi Maruoka has tried 40 different combinations, and analyzed their constituent parts.

    "Tea from the leaves of sakura or apple trees have a fruity aroma. They have merit as health teas, too, and because they don't need to be heated up during production, they're better for the environment," he said. Day and night, he continues his research in hopes of commercializing the brews.

    Maruoka is a second-year master's course student in agriculture at the university, and lives in Kyoto's Sakyo Ward. A member of the institution's chemical ecology research laboratory, he raised gypsy moth larvae on sakura leaves using the large stockpile of caterpillars his senior colleagues had acquired. In May 2021, Maruoka tried pouring boiling water over some of the larvae's dried excrement and drinking it. He found the concoction had a similar fragrance and flavor to black tea, and he hasn't looked back since.

    Chongshicha is traditionally consumed in part of China, and teas made with feces from moth larvae fed certain leaves are highly prized. Maruoka aimed to make a more fragrant and flavorful tea, and took samples of plants and insects from several areas. He set up his operation with some 20 insect varieties including the Asian swallowtail, and seeds from 17 plant species including corn and mikan mandarin oranges. The different insects were fed the leaf varieties in the search for the ultimate combination.

    Over the next half year, Maruoka's team found two permutations they thought were truly delicious. The tea made with excrement from gypsy moth larvae that ate apple leaves had a pleasant taste, and the brew made by feeding leaves of the Japanese blue oak -- which grow acorns -- to lobster moths was found to taste similar to luxury-grade Chinese tea. Other lab researchers who taste-tested them also praised the teas.

    Chemical analysis of chongshicha showed that depending on the combination, there were large quantities of the chemical flavor components including coumarin, geraniol, and theanine that gives tea its deep flavor, and healthy polyphenols. It's thought that the larvae's digestive process also boosts the flavors and beneficial bacteria.

    The production process for sencha green tea, which is widely consumed in Japan, includes steaming the leaves and then drying them with hot air. But in the case of chongshicha, the feces are dried naturally, and to drink it all people need to do is remove the impurities and add hot water. Sakura and apple leaves are also basically caffeine-free, making it a decaf tea.

    Takeshi Maruoka, who has tested various combinations of plants and insects in his quest to make consumption of chongshicha more widespread, is seen in this image taken at Kyoto University in Sakyo Ward, Kyoto, on Jan. 7, 2022. (Mainichi/Norikazu Chiba)

    Maruoka emphasized, "I think people might give it a wide berth and think it's gross when they hear it's an insect feces tea, but we use plants and insects that have had no history of toxicity to humans when ingested orally, and they only eat the leaves, so the feces is not dirty."

    He added, "They also line up with the U.N. Sustainable Development Goals, and it's all based on combinations of insects and leaves, meaning the possibilities are endless. I'd like many people try it at least once."

    The researchers are looking for businesses to help turn the teas into commercial products. Businesses can contact Maruoka at maruoka.tsuyoshi.82n@st.kyoto-u.ac.jp (Japanese language only).

    (Japanese original by Norikazu Chiba, Kyoto Bureau)

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