农业工程学报
農業工程學報
농업공정학보
Transactions of the Chinese Society of Agricultural Engineering
2015年
18期
247-255
,共9页
何余勤%胡荣锁%张海德%娜娜%蔡涛%彭健%许英豪
何餘勤%鬍榮鎖%張海德%娜娜%蔡濤%彭健%許英豪
하여근%호영쇄%장해덕%나나%채도%팽건%허영호
主成分分析%识别%农产品%咖啡特征香气%焙烤%SPME-GC-MS%电子鼻%分类
主成分分析%識彆%農產品%咖啡特徵香氣%焙烤%SPME-GC-MS%電子鼻%分類
주성분분석%식별%농산품%가배특정향기%배고%SPME-GC-MS%전자비%분류
principal component analysis%identification%agricultural products%coffee characteristic aroma%roasting%SPME-GC-MS%electronic nose%classification
为研究咖啡香气与焙烤条件的联系，进一步提供合理的加工条件生产特定香气的咖啡，减少咖啡多样化的生产成本。以海南阿拉比卡咖啡豆为试材，利用固相微萃取的气质联用（solid phase microextraction-gas chromatographic-mass spectrometric，SPME-GC-MS）结合电子鼻对不同焙烤温度处理6 min的咖啡挥发性化合物和特征性香气进行检测。结果表明：咖啡中总共检测出43种化合物，咖啡在30（室温）、80、100℃时挥发性组分主要为醇类、醚类与胺类以致香气不足，随着温度继续升高，逐渐热解生成芳香化合物，咖啡在120℃时开始出现糠醛、吡嗪与吡咯等，呋喃、醛类、吡嗪和吡咯的含量均在140℃时达到峰值，吡唑和咪唑只在160℃时产生且质量分数为2%～3%；电子鼻传感器T30/1、70/2、PA/2、P30/2与LY2/AA能有效地分析咖啡香气变化，主成分分析（principal component analysis，PCA）与判别因子分析（discriminant factorial analysis，DFA）有效地区分了不同焙烤程度的咖啡香气，层序聚类分析（hierarchical cluster analysis， HCA）成功将咖啡分为未焙烤、浅度焙烤、中度焙烤和深度焙烤四类。结果表明，随着焙烤温度的上升，咖啡中芳香醛、酚类、呋喃、吡嗪、吡咯和咪唑等挥发性化合物不断增加，进而改变咖啡的特征性香气，SPME-GC-MS结合电子鼻技术能实现咖啡挥发性组分、香气表型和焙烤程度三者之间有机地结合，以用于对咖啡焙烤程度的区别，该研究结果为生产某些特定香气咖啡的工艺提供科学依据和技术支持。
為研究咖啡香氣與焙烤條件的聯繫，進一步提供閤理的加工條件生產特定香氣的咖啡，減少咖啡多樣化的生產成本。以海南阿拉比卡咖啡豆為試材，利用固相微萃取的氣質聯用（solid phase microextraction-gas chromatographic-mass spectrometric，SPME-GC-MS）結閤電子鼻對不同焙烤溫度處理6 min的咖啡揮髮性化閤物和特徵性香氣進行檢測。結果錶明：咖啡中總共檢測齣43種化閤物，咖啡在30（室溫）、80、100℃時揮髮性組分主要為醇類、醚類與胺類以緻香氣不足，隨著溫度繼續升高，逐漸熱解生成芳香化閤物，咖啡在120℃時開始齣現糠醛、吡嗪與吡咯等，呋喃、醛類、吡嗪和吡咯的含量均在140℃時達到峰值，吡唑和咪唑隻在160℃時產生且質量分數為2%～3%；電子鼻傳感器T30/1、70/2、PA/2、P30/2與LY2/AA能有效地分析咖啡香氣變化，主成分分析（principal component analysis，PCA）與判彆因子分析（discriminant factorial analysis，DFA）有效地區分瞭不同焙烤程度的咖啡香氣，層序聚類分析（hierarchical cluster analysis， HCA）成功將咖啡分為未焙烤、淺度焙烤、中度焙烤和深度焙烤四類。結果錶明，隨著焙烤溫度的上升，咖啡中芳香醛、酚類、呋喃、吡嗪、吡咯和咪唑等揮髮性化閤物不斷增加，進而改變咖啡的特徵性香氣，SPME-GC-MS結閤電子鼻技術能實現咖啡揮髮性組分、香氣錶型和焙烤程度三者之間有機地結閤，以用于對咖啡焙烤程度的區彆，該研究結果為生產某些特定香氣咖啡的工藝提供科學依據和技術支持。
위연구가배향기여배고조건적련계，진일보제공합리적가공조건생산특정향기적가배，감소가배다양화적생산성본。이해남아랍비잡가배두위시재，이용고상미췌취적기질련용（solid phase microextraction-gas chromatographic-mass spectrometric，SPME-GC-MS）결합전자비대불동배고온도처리6 min적가배휘발성화합물화특정성향기진행검측。결과표명：가배중총공검측출43충화합물，가배재30（실온）、80、100℃시휘발성조분주요위순류、미류여알류이치향기불족，수착온도계속승고，축점열해생성방향화합물，가배재120℃시개시출현강철、필진여필각등，부남、철류、필진화필각적함량균재140℃시체도봉치，필서화미서지재160℃시산생차질량분수위2%～3%；전자비전감기T30/1、70/2、PA/2、P30/2여LY2/AA능유효지분석가배향기변화，주성분분석（principal component analysis，PCA）여판별인자분석（discriminant factorial analysis，DFA）유효지구분료불동배고정도적가배향기，층서취류분석（hierarchical cluster analysis， HCA）성공장가배분위미배고、천도배고、중도배고화심도배고사류。결과표명，수착배고온도적상승，가배중방향철、분류、부남、필진、필각화미서등휘발성화합물불단증가，진이개변가배적특정성향기，SPME-GC-MS결합전자비기술능실현가배휘발성조분、향기표형화배고정도삼자지간유궤지결합，이용우대가배배고정도적구별，해연구결과위생산모사특정향기가배적공예제공과학의거화기술지지。
The aim of the study is to investigate the relationships between coffee aroma and banking conditions so as to provide theory reference for accurately selecting reasonable processing conditions for special fragrance of coffee and reducing the production cost of coffee diversification. The Hainan Arabica coffee was used as material, and we made use of the solid phase microextraction-gas chromatographic-mass spectrometric (SPME-GC-MS) and the electronic nose to detect the volatile compounds and characteristic aroma of coffee processed under several baking temperatures for 6 min. The results showed that a total of 43 kinds of volatile compounds were detected. When the baking temperature was lower than 120℃, volatile components of coffee mainly included alcohols, ethers and amine which slightly contribute to coffee aroma. With the temperature increasing, aromatic compounds were gradually generated from the pyrolysis of coffee endogenous compounds. Furthermore, pyrazine and pyrrole of coffee volatile compounds began to appear at 120℃. The contents of furan, aldehydes, pyrazine and pyrrole, such as 2-acetyl-5-methylfuran, 2,6-diethyl-pyrazine, 5-methyl-2-furancarboxaldehyde and 1-(2-furanylmethyl)-pyrrole, all peaked at 140℃. Parazole and imidazole, whose contents were less than 3%, only were detected at 160℃. At the same time, the content of volatile compounds changed irregularly because of the pyrolysis reaction of esters, phenols and ketones. After processing at different temperatures, the fragrance was composed of a large number of complex components which were able to lead to sensor inductive effect of electronic nose. Moreover, all of the response values were significantly different according to Tukey’s multiple-range test at theP<0.05 level. However, part of the sensors of electronic nose could effectively analyze the variation of coffee characteristic flavor, such as the sensor T30/1, 70/2, PA/2, P30/2 and LY2/AA. Both the principal component analysis (PCA) and the discriminant factorial analysis (DFA) performed well when they were used to analyze coffee samples, with the first 2 principal components (PCs) explaining 100% and the first 2 factors explaining 100% of the variations of coffee aroma, which could effectively discriminate the coffee aroma with different roasting degrees. The hierarchical cluster analysis (HCA) successfully clustered the different types of coffee into 4 groups which included raw coffee, light roast coffee, medium roast coffee and dark roast coffee. The raw coffee could be divided into the first class which mainly clustered alcohol, esters and alkane. The second species, including 80℃ and 100℃ samples, was likely to cluster the first PC and the first discriminant factor, which was regarded as light roast coffee. A part of coffee may be classified as medium roast coffee at 120℃ and 140℃ owing to esters, phenols, aldehydes, amine, pyrazine and pyrrole. When processing at 160℃, volatile components of coffee mainly contained plenty of aromatic compounds such as heptyl ether, 4-ethyl-2-methoxyphenol, 5-methylfuran-2-carbaldehyde and 1-(furan-2-ylmethyl)-1H-pyrrole, in other words, this kind was categorized as dark roast coffee. It was observed that, the higher the baking temperature was, the more easily the samples were discriminated with different volatile compounds. Therefore, the relationships among the roasted coffee volatile compounds, the special fragrance and the roasting degree were determined by the SPME-GC-MS in combination with the electronic nose, which contributed to discriminate different roasting degrees of coffee. The research results can provide scientific basis and technical support for selecting the production process to roast particular aroma of coffee.
