咖啡是我国重要的热带饮料作物之一，香气不仅是影响咖啡风味的主要因素，也是评价咖啡品质的一个重要指标。前期研究中发现，我国主栽咖啡品种表现出不同的香气品质特点，而对品种间特征香气差异的化学基础物质研究较少且呈香机理尚不明晰，影响了我国咖啡品种区域化种植及产品风味稳定和质量控制。针对上述问题，本研究拟采用液液萃取、固相微萃取等前处理方法，结合气相色谱-质谱联用和二维气相色谱-高分辨飞行时间-质谱联用等技术对咖啡中香气成分进行分析；采用气相色谱-嗅觉测量法，明确其特征香气成分，应用主成分分析等方法探索品种间香气差异的化学本质；利用电子鼻技术结合化学计量学的模式识别技术建立咖啡特征香气表征和识别模型，优选最适预测模型；建立咖啡特征香气成分与感官特征的相关性数学模型，探索特征香气成分的呈香机理。研究结果为促进咖啡品种区域化种植和提高产品质量提供指导，为提高我国咖啡研究水平和咖啡产业发展提供理论参考。

Coffee is one of the most important tropical beverages in China, aromatic components is the major factor that not only influences coffee flavor, but can be used as an important index to evaluate coffee quality. Our previous studies indicated that different coffee varieties displayed different characteristics of aromatic attributes, but what reason result in aromatic difference between different varieties and the aroma composition mechanism is unclear. In allusion to above-mentioned problems, pretreatment methods such as liquid-liquid extraction, solid-phase micro-extraction combined with gas chromatography-mass spectrometry, comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry were applied to analyze the aromatic profile of coffee. Gas chromatography-olfactometry was done to identify the characteristic aromatic components, principal component analysis and other methods, etc. were employed to explore the chemical properties which lead to the difference among coffee varieties. Electronic nose technology in combination with pattern recognition technologies was utilized to construct the aromatic extract discrimination model, and the optimal model was obtained through comparison of model performances. The mathematic model was constructed to correlate the characteristic aromatic components and sensory analysis result to explore the aroma composition mechanism. Research results can promote regional plantation of coffee varieties and as a guidance to improve the quality of products and industrial development.

咖啡是我国热区主要的饮料作物之一，香气对于咖啡的品质评价至关重要，也是消费者选择咖啡的主要因素之一。不同品种咖啡的香气成分存在差异，明确不同品种咖啡间香气存在差异的化学物质基础对于咖啡品种区域化和产品风味品质稳定尤为重要。本研究通过高效液相色谱-二极管阵列检测器、气相色谱-火焰离子检测器、氨基酸分析仪、顶空固相微萃取-气相色谱质谱联用及电子鼻技术检测生咖啡豆和烘焙豆中主要风味前体物、香气物质及香气电子感官表达谱，并结合一元方差分析、主成分分析、系统聚类分析等统计学方法解析多元数据，结果表明：生咖啡豆中主要脂肪酸为亚油酸、软脂酸和花生酸，亮氨酸（0.84 g/100 g DW）、赖氨酸（0.63 g/100 g DW）和精氨酸（0.61 g/100 g)为主要的必需氨基酸，生咖啡豆中共鉴定出79种挥发性化合物；电子鼻的时间-强度动态分析图、传感器特征响应值及相对标准偏差分析表明，不同品种间存在差异的传感器主要为PA/2和T70/2；通过GC-MS对浅度、中度和深度样品分别鉴定出55种、56种和64种香气成分，七个品种样品在PCA二维投影图上除部分重叠外，其余样品能够按各自特性聚为一类，X1样品与1-羟基-2-丙酮、3,5-二乙基-2-甲基吡嗪、3-甲基吡嗪、2-乙酰基吡啶相关性较大、RY1样品与圆点位置较近，与糠酯、苯酚有相关性，但相关性不大，RY2样品与3-甲基苯酚、2,3-二甲基吡嗪、3-羟基-6-甲基吡啶相关性较大，X24-2样品与4-乙基-2-甲氧基苯酚、麦芽酚相关性较大，X26样品与苯酚、2,3-二氢-3,5-二羟基-6-甲基-4-吡喃酮、3-甲基苯酚相关性较大，X28样品与载荷4-甲基苯甲醛、3-甲基丁醛相关性较大，XCM样品与3-甲基-2-丁烯酸、2-乙酰基呋喃、麦芽酚相关性较大。通过本研究对不同品种咖啡的风味前体物及香气物质进行差异性分析，明晰品种间香气存在差异的化学物质基础对于咖啡品种选育、烘焙加工及产品风味品质调控具有重要意义。