Cheonggukjang, Korea’s traditional fermented soybean paste, contains the highest proportion of bioavailable isoflavones among processed soybean foods. (Image courtesy of Pixabay/CCL)
SEOUL, May 22 (Korea Bizwire) – A new government study has found that cheonggukjang, Korea’s traditional fermented soybean paste, contains the highest proportion of bioavailable isoflavones among processed soybean foods, highlighting its superior health benefits.
According to research released Thursday by the Gyeonggi Institute of Health and Environment, cheonggukjang leads in the proportion of non-glycosylated (aglycone) isoflavones—compounds more easily absorbed by the human body—at 38.49%.
These compounds are known for mimicking estrogen’s beneficial effects, such as lowering the risk of cardiovascular disease, osteoporosis, and hormone-related cancers.
Other soybean products followed far behind, with biji (soy pulp) at 15.14% and podubu (soy skin) at 13.05%.
Isoflavones are naturally found in soybeans primarily in glycoside (bound) form, which is less readily absorbed. They must be converted into the aglycone form to be effectively utilized by the body. While total isoflavone content is important, researchers emphasized that absorption efficiency is the key to physiological benefits.
In terms of total isoflavone content, dry soybean products ranked highest. Raw soybean powder topped the list with 3,209.65 mg/kg, followed by puju (dried tofu skin) at 2,953.39 mg/kg and roasted soybean powder at 2,596.70 mg/kg. Moist products like tofu (495.93 mg/kg), biji (412.88 mg/kg), sundubu (soft tofu, 410.85 mg/kg), and soy milk (233.27 mg/kg) contained significantly less.
Kim Ki-chul, director of the Food and Drug Research Division at the institute, said, “This study not only measured the total isoflavone content in common soy foods, but also analyzed their usable forms—providing valuable insight to help consumers make more informed dietary choices.”
The findings come amid growing public interest in plant-based nutrition and functional foods, particularly as Korea’s aging population increasingly turns to dietary options for preventive health care.
Lina Jang (linajang@koreabizwire.com)
