Abstract: The Momordica charantia seed proteins were extracted and separation by polyethylene glycol/ammonium sulfate aqueoustwo-phase system. The factors affecting system distribution coefficients, recycling rate, and extracting agents were investigated and the optimal conditions of M. charantia seed proteins extraction were confirmed. Under the conditions of mass fraction of PEG6000 as 22% and (NH₄)₂SO₄ as 25%, the smallest distribution coefficient obtained as 0.089 and the recovery was 96%. The results of SDS-PAGE showed that M. charantia seed protein were polymer globulin of 12S (327 KD) with major subunits 50 KD, 43 KD, and 10 KD, which were connected with disulfide bonds by low molecular weight protein subunits (<35kD). The results of antimicrobial activities analysis showed that the proteins had strong inhibition to testing bacteria and fungi, whose MIC were far below the value of sodium benzoate, and which were very stable under the environment of low temperature, acid, ultraviolet, and inorganic salt. In addition, the test also showed total antioxidative activity and clearance on •OH free radical of the proteins were obvious. Therefore, the M. charantia seed proteins had the significant antioxidant capacity and broad-spectrum antimicrobial activity.

Key words: Momordica charantia seed protein, aqueous two-phase system, extraction and separation, antimicrobial activities, antioxidant activity.