<；P>；PROBLEM TO BE SOLVED: To provide a method for producing an antioxidant from kefir: fermented milk, a method of identifying the same, and a diabetes treating agent, a tissue repairing agent having DNA repairing action and a health food each using kefir. <；P>；SOLUTION: The antioxidant production method by using kefir comprises a first process for obtaining a supernatant by precipitating milk fat component by centrifuging the kefir, a second process for obtaining an outer liquid of molecular weight 1,000 or less by dialyzing the supernatant with a dialyzing film of molecular weight cut-off 1,000, a third process for obtaining a separated liquid by removing precipitate generated by neutralizing with an alkali a concentrated liquid generated by concentrating the outer liquid, a fourth process for obtaining an inner liquid of a molecular weight 100 or more by dialyzing the separated liquid with a dialyzing film of molecular weight cut-off 100, and a fifth process for identifying and fractionally collecting an antioxidant substance by using an on-line HPLC (high-performance liquid chromatography) method； the method of identifying the antioxidant； the antioxidant； the diabetes treating agent； and the tissue repairing agent having DNA repairing action； are provided. <；P>；COPYRIGHT: (C)2009,JPO&INPIT
