Abstract
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.