전자코를 이용한 브라질 커피의 결점두와 비결점두 차이 비교
Discrimination between defective and non-defective Brazilian coffee beans using electronic nose
- 주제(키워드) 도움말 coffee , flavor , physico-chemical , e-nose , Brazil , Arabica
- 발행기관 강릉원주대학교 일반대학원
- 지도교수 도움말 윤정로
- 발행년도 2019
- 학위수여년월 2019. 8
- 학위명 석사
- 학과 및 전공 도움말 일반대학원 식품가공유통학과
- 실제URI http://www.dcollection.net/handler/kangnung/000000010456
- UCI I804:42001-000000010456
- 본문언어 한국어
초록/요약 도움말
The quality of coffee bean depends on the harvest time, processing method, storage and manufacturing method. If the proper storage conditions and distribution conditions are not maintained, the quality will change easily. Therefore, the defective coffee bean can be produced quite often when processed improperly at the harvest time on the farm. Methodology to discriminate defective coffee in green bean have been developed in many ways. However, discrimination of the defects in the roasted bean is currently insufficient except for chromaticity and cupping. In this study, it was conducted to find out whether the electronic nose could be used as an objective indicator in assessing coffee grade. Analysis of the green beans revealed that the moisture contents of insect damaged bean (I), unripe bean (U), sour bean (S) and non-defective bean (ND) were 8.38, 8.54, 8.16, and 9.29%, respectively indicating that non-defective bean was significantly different (p<0.05) from 3 defective beans in moisture content. For roasted coffee beans, physicochemical analysis such as moisture content, bulk density, total phenolic content, antioxidant activity, caffeine, chlorogenic acid, trigonelline, etc. as well as electronic nose was conducted. The moisture content and bulk density of roasted bean were in the range of 1.04-1.31% and 0.317-0.335 g/cm3, respectively. Other parameters analyzed after roasting showed no significant differences at 5% level: caffeine (10.52-11.02 mg/g ), chlorogenic acid (5.16-5.59 mg/g), trigonelline (7.81-8.18 mg/g), total acidity (0.95-1.02%) and soluble content (1.5-1.6 °Bx) The feasibility of employing e-nose was tested for discrimination between defective and non-defective coffees after roasting and grinding. Defective (insect damaged, unripe and sour) and non-defective coffee beans were roasted at 205℃. Separation of the coffee samples into four groups (I, U, S and ND) by principal component analysis (PCA) was possible only when the samples were supplied to e-nose in the extracted form, not in the power form. Separation of defective and non-defective coffee beans was tested by PCA using different proportion of defective beans such as 100%, 50%, 30% and 10% vs. non-defective bean. Out of 4 different proportion, 50% defective beans of 3 kinds (insect damaged, unripe and sour) along with non-defective bean showed the best separation having discrimination index, 81. Discriminant function analysis (DFA) also provided separation of the sample into 4 groups successfully. On DFA plot, test sample having 10% defective bean positioned next to the reference bean (30% defective) toward non-defective bean which was positioned opposite side of the defective beans. In conclusion, separation of defective beans and non-defective bean is successful in both PCA and DFA. However, it is not easy to detect defective bean from unknown samples.
more목차 도움말
Ⅰ. 서론 ·································································································· 1
1. 연구 배경 ·························································································· 1
2. 연구 목적 ·························································································· 6
Ⅱ. 재료 및 방법 ····················································································· 8
1. 실험재료 ··························································································· 8
1.1. 생두 샘플 ···················································································· 8
1.2. 시약 ···························································································· 8
2. 실험 방법 ························································································ 11
2.1. 수분 ·························································································· 11
2.2. 색도 ························································································ 11
2.3. 로스팅 및 분쇄 ··········································································· 11
2.4. 총 중량손실(Weight loss, %) ······················································· 11
2.5. 디벨롭 시간 비율(Development time ratio, DTR) ·························· 12
2.6. 겉보기 밀도 ·············································································· 12
2.7. 카페인, 클로로겐산 및 트리고넬린 ··············································· 12
2.7.1. 표준 검량선 ·········································································· 12
2.7.2. 시료 추출 및 HPLC ······························································ 12
2.8. 총 페놀 함량 ·············································································· 14
2.9. DPPH 라디칼 소거활성 ······························································· 14
2.10. 총 산도 및 pH ········································································ 14
2.11. 당도 ························································································ 15
2.12. 전자코(E-nose) ········································································ 15
2.12.1. 추출 ·················································································· 15
2.12.2. Heracles Ⅱ E-nose를 이용한 프로필 ··································· 15
2.12.3. 휘발성 및 향기 화합물의 동정 ··············································· 18
2.13. 통계 ························································································ 18
2.13.1 Alpha Soft 소프트웨어를 이용하여 전자코 분석 ······················ 18
2.13.2. PCA ·················································································· 18
2.13.3. DFA ·················································································· 18
Ⅲ. 결과 및 고찰 ··················································································· 19
1. 생두의 물리적 특성 ·········································································· 19
2. 로스팅, 총 중량손실률 및 DTR ·························································· 21
3 원두의 물리적 특성 ··········································································· 24
4. 원두의 화학적 특성 ·········································································· 26
4.1. 카페인, 클로로게산, 트리고넬린 및 당도 ········································ 26
4.2. 총 산도(TTA)와 pH ···································································· 30
4.3. 총 페놀 함량(TPC), 라디칼 소거 활성(RSA) ··································· 30
5. 전자코(E-nose) 분석 ········································································ 32
5.1. Kovats standard(mixture of C6-C16 alkanes) ····························· 32
5.2. Sensor 선택 ·············································································· 32
5.3. PCA 분석 ·················································································· 32
5.4. DFA 분석 ·················································································· 41
Ⅳ. 결론 ································································································ 51
참고문헌 ······························································································· 52
