建立一種氣體分析方法學：以熱脫附儀氣相層析質譜儀分析咖啡豆風味

To Establish a Methodology for Gas Analysis: Using TD-GC-MS System to Analyze Coffee Beans Aroma

栗嘉徽(Chia-Hui Li)

指導教授 ： 饒達仁

國立清華大學/工學院/奈米工程與微系統研究所/碩士(2013年)

摘要

本研究利用熱脫附儀串聯氣相層析質譜儀(TD-GC-MS)分析不同烘培程度的咖啡豆風味，並搭配Tenax-TA吸附管以及低流量的採樣幫浦進行咖啡氣味的採樣。不同烘培條件賦予咖啡豆不同的風味，這些風味成分主要是經由烘培過程中所發生的一系列化學反應而形成。我們利用GC-MS鑑定出17種咖啡豆的主要風味成分，結果顯示大部分成分都隨烘培程度而增加，但Furfurals類的成分卻隨著烘培程度下降。
　　另外，我們也提出在烘培中可能發生的化學反應機制與途徑，加以說明風味成分的變化與趨勢。咖啡豆的存放時間和量測間隔也會影響實驗結果，不同風味成分有不同的隨著存放時間的變化趨勢，而成分的分子量、沸點、與化學結構可能是影響變化趨勢的主要因素；由2-methyl-furan的變化趨勢來看，量測間隔越長，成分的下降速度較為緩慢。

關鍵字

熱脫附儀 ； 氣相層析質譜儀 ； 咖啡豆

並列摘要

This research was to demonstrate the TD-GC-MS system and realize the idea of gas measurement and analysis, roasted coffee beans were chosen as our study target. Tenax-TA adsorbent tubes and a low flow rate pump were used to collect the coffee beans aroma. Then the adsorbent tube was submitted to TD-GC-MS for analysis. Different roasting conditions would give the coffee beans aroma various smells and taste characteristics. This is due to the complex chemical reactions occurred during the roasting process. 17 major components have been identified by GC-MS. Results showed that most components in coffee beans aroma increased with roast levels, while furfurals family had a downward tendency. A mechanism of the formation of furfural was proposed to explain the decrease in furfural. Storage time and monitoring intervals were also two factors that can affect the measurement results. Components had their own specific trends of change in their intensity over the storage period. This can be due to the molar mass, boiling points, and chemical structures. As the monitoring intervals prolonged, which means less sampling frequency, we found that the intensity of 2-methyl-furan significantly decayed at a slower rate.

並列關鍵字

Thermal Desorption ； GC-MS ； coffee beans aroma

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