The present invention provides a koji fermentation composition in which the amount of citric acid produced is reduced without losing the acidic protease activity and xylanase activity of Koji koji, and a method for producing the same. The koji fermented composition is obtained by inoculating and culturing black koji mold on tea leaves.黒麹菌を用いた際に、黒麹菌の酸性プロテアーゼ活性やキシラナーゼ活性は失わずに、クエン酸生成量を低減させた麹発酵組成物及びその製造方法を提供する。麹発酵組成物は、茶葉に黒麹菌を接種し、培養することにより得られる。