This study was performed to evaluate the quality characteristics and antioxidant activity of Nurungji by varying the purple sweet potato powder addition time (AR: added after rice cooking, BR: added before rice cooking) and powder ratio (0, 2, 4, 6, 8%) on the prepared rice during Nurungji’s manufacturing. In both AR and BR samples, water binding capacity, soluble solid content, reducing sugar, and hardness increased with an increasing proportion of purple sweet potato powder; however, the pH and moisture content decreased. The L value and b value decreased and increased with the influence of anthocyanin in purple sweet potato powder. The total polyphenol, flavonoid, anthocyanin contents, DPPH, and ABTS radical scavenging activity were highest in Nurungji with 8% of purple sweet potato powder. Moreover, AR samples showed higher antioxidant activity than BR samples. Based on the study results above, the preparation of Nurungji with 8% purple sweet potato powder by AR process was more favorable based on the content of antioxidants and antioxidant activity.

Abstract
서 론
재료 및 방법
    재료
    누룽지 제조
    pH 및 색도
    수분함량 및 수분결합능력
    가용성 고형물 함량 및 환원당
    경도
    총 폴리페놀 함량 및 플라보노이드 함량
    총 안토시아닌 함량 측정
    DPPH 및 ABTS 라디칼 소거 활성 측정
    통계처리
결과 및 고찰
    수분함량 및 수분결합능력
    가용성 고형물 함량 및 환원당
    pH
    색도 및 경도
    총 폴리페놀 및 플라보노이드 함량
    총 안토시아닌 함량
    DPPH 및 ABTS 라디칼 소거 활성
요 약
Acknowledgements
References

• 용지은(서울과학기술대학교 식품공학과) | Ji-Eun Yong (Department of Food Science and Technology, Seoul National University of Science and Technology)
• 강성태(서울과학기술대학교 식품공학과) | Sung-Tae Kang (Department of Food Science and Technology, Seoul National University of Science and Technology) Corresponding author