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Subcritical Water Hydrolysis of Pumpkin Leaves and their Antioxidant Activities

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Abstract
Enhanced production of individual phenolic compounds by subcritical water hydrolysis of pumpkin leaves was investigated at various temperatures ranging from 100°C to 220°C for 20 min and at various reaction times ranging from 10 min to 50 min at 160°C. Caffeic acid, p-coumaric acid, ferulic acid, and gentisic acid were major phenolic compounds in the hydrosate of pumpkin leaves. All phenolic compounds except gentisic acid showed the highest yield at 160°C, and gentisic acid showed the highest yield at 180°C. The cumulative amount of individual phenolic compound gradually increased by 48.1, 52.2, and 78.4 μg/g dry sample at 100°C, 120°C, and 140°C, respectively, and then greatly increased by 1,477.1 μg/g dry matter at 160°C. The yields of caffeic acid and ferulic acid showed peaks at 20 min while those of cinnamic acid, p-coumaric acid, p-hydroxybenzoic acid, and procatechuic acid showed peaks at 30 min. Antioxidant activities such as 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) values gradually increased with hydrolysis temperature, and were ranged from 6.77 to 12.42 mg ascorbic acid equivalents/g dry matter and from 4.25 to 8.92 mmol Fe2+/100 g dry matter, respectively. L and b values were gradually decreased as hydrolysis temperature increased from 100°C to 140°C. At high temperatures (160°C to 220°C), L and b values were decreased suddenly and were leveled off. a value showed peak at 160°C and then decreased as temperature increased from 160°C to 220°C. These results suggest that subcritical water hydrolysis of pumpkin leaves was strongly influenced by temperature and may enhanced production of phenolic compounds and antioxidant activities.
페놀 화합물의 생산을 증진시키기 위해 호박잎을 아임계수 처리 온도((100-220°C, 20 min)와 처리 시간(10-50 min, 160°C)을 달리하여 가수분해하였다. 호박잎 가수분해물의 주요 페놀 성분은 caffeic acid, p-coumaric acid, ferulic acid와 gentisic acid이었다. 대부분의 페놀 화합물은 160°C에서 최고 함량을 보였으나 gentisic acid의 경우는 180°C에서 최고 함량을 나타내었다. 총페놀 화합물의 양은 100°C, 120°C, 140°C에서 각각 48.1, 52.2, 78.4 μg/g dry matter로 가수분해 온도의 증가에 따라 점차 증가하는 경향을 보였으며, 160°C에서 1,447.1 μg/g dry matter로 최고 함량을 나타내었다. 그러나 160°C 이상의 온도에서는 총페놀 화합물의 수율은 감소하는 경향을 보였다. Caffeic acid와 ferulic acid는 20 min에서, cinnamic acid, p-coumaric acid, p-hydroxybenzoic acid, 그리고 protocatechuic acid는 30 min에서 가장 높은 함량을 보였다. 항산화 활성은 온도 증가에 따라 DPPH는 6.77-12.42 mg ascorbic acid equivalents/g dry matter, FRAP은 4.25-8.92 mmol Fe2+/100 g dry matter 값을 보였다. 색차 분석에서는 L과 b 값이 가수분해 온도가 100-140°C로 증가했을 때는 서서히 감소하는 경향을 보였으나, 높은 온도 (160-220°C)에서는 급격하게 감소하는 경향을 보였다. a 값의 경우 100-160°C에 이르기 까지 서서히 올라가고 160°C에서 최고점을 나타냈지만, 온도가 증가할수록 감소하는 경향을 보였다. 이상의 결과로부터 호박잎의 아임계수 가수분해물은 가수분해 시간보다는 온도의 영향이 더 큰 것으로 나타났으며, 페놀 화합물 함량과 항산화 활성을 증가시키는데 도움을 줄 것으로 추정되었다.
Author(s)
고정연
Issued Date
2016
Awarded Date
2016. 8
Type
Dissertation
URI
http://dcoll.jejunu.ac.kr/jsp/common/DcLoOrgPer.jsp?sItemId=000000007659
Alternative Author(s)
Ko, Jeong-Yeon
Department
대학원 식품공학과
Advisor
임상빈
Table Of Contents
Abstract 1
1. Introduction 2
2. Materials and methods 4
2.1. Materials 4
2.2. Subcritical water hydrolysis 6
2.3. Determination of phenolic compounds by GC/MS 8
2.4. Determination of antioxidant activity 9
2.5. Color measurement 10
2.6. Statistical analysis 10
3. Results and discussion 11
3.1. Yields of phenolic compounds 11
3.2. Antioxidant activities 15
3.3. Color values 18
4. Conclusion 21
국문요약 22
References 23
Degree
Master
Publisher
제주대학교 대학원
Citation
고정연. (2016). Subcritical Water Hydrolysis of Pumpkin Leaves and their Antioxidant Activities
Appears in Collections:
General Graduate School > Food science and Engineering
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