Lactic Acid Bacteria (LAB) are among the representative probiotics that have been used for a long time in fermented food. Although there are many studies on detecting the radical scavenging activity of LAB, few studies have been conducted on the environmental factors that improve scavenging activity. This study investigated the environmental factors affecting the DPPH radical scavenging and various antioxidant activities of Kimchi-derived Lactobacillus plantarum K-21 with antihypertensive and radical scavenging activities. The optimal conditions for scavenging DPPH radicals were glucose 2%, bactopeptone 0.5%, Tween 80 0.05%, L-cysteine 0.05%, and an initial pH 6.5 at 35℃. Under optimal conditions, the DPPH radical scavenging activity was 94.8±2.2%, which was 1.5 times higher than that of the basic medium. In addition, L. plantarum K-21 had other antioxidant activities; ABTS radical scavenging (93.6±1.5%), hydroxyl radical scavenging (8.5±0.9%), metal chelating (65.9±0.5%), NO scavenging (53.1±19%), SOD-like (25.1±1.5%), and reducing power (11.7±1.4%) activities were detected. Therefore, L. plantarum K-21 may act not only as a starter for lactic acid-fermented foods with improved functionality but also as a drug for various diseases caused by oxidative stress.

Abstract
1. 서 론
2. 재료 및 방법
    2.1. 사용 균주 및 배양조건
    2.2. 실험균주의 DPPH 라디칼 제거능에 대한 환경요인의 영향
    2.3. 라디칼 제거 활성 및 항산화 활성 측정법
3. 결과 및 고찰
    3.1. DPPH 라디칼 제거능을 위한 환경요인 최적화
    3.2. 최적조건에서 시간에 따른 DPPH 라디칼 제거활성
    3.3. 실험균주의 다양한 라디칼 제거 및 항산화 활성
4. 결 론
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