生咖啡豆在不同烘焙條件下焙炒後所調製咖啡之成分分析

Abstract

在國產咖啡豆樣品中，烘焙終點溫度愈高，則取樣調配所得咖啡之中pH值即愈高，且有機酸含量會隨著溫度的上升而下降。總酚含量也會隨著溫度的上升而下降。在色澤方面，終點烘焙溫度愈高，L值愈低，而a值及b值則愈高，但超過210℃以上，則a值及b值受溫度的影響則會趨緩。以210℃為烘焙終點溫度，取樣所得之咖啡中咖啡因含量最高。有機酸中以quinic acid含量最高，含量隨著烘焙溫度的上昇而下降，而formic acid以及fumaric acid含量則偏低。在儲藏期間，無論何種烘焙終點溫度，其pH值及色澤皆無明顯差異，咖啡因及總酚含量則會稍微上升。Oxalic acid及Malic在儲藏間變化不明顯，Quinic acid及Citric acid含量在儲藏期間稍稍上升。與進口豆之比較，進口豆在相同的烘焙終點溫度下，以國產豆經烘焙後調製所得咖啡之pH值、總酚含量、a值、b值、咖啡因含量及香氣成分較低，L值則無明顯之差異。將國產及進口生咖啡豆以230℃及250℃熱裂解兩分鐘的處理中，國產之生咖啡豆之香氣總量較少，但此這些成分皆為極性較低之成分，尚無法代表全部之咖啡香氣。六種有機酸不會在何種烘焙終點溫度之處理中，皆以台灣豆之有機酸含量最高。國產咖啡豆經不同烘焙條件焙炒後以真空包裝及LDPE夾鍊袋包裝儲藏四週後調製咖啡中，以真空包裝袋包裝之樣品有較低之總酚以及較高之pH值，但兩者差異不明顯，且有機酸部分也有類似pH值之趨勢。真空包裝袋包裝以210℃為烘焙終點溫度的國產豆，儲藏四週後咖啡因含量明顯低於以LDPE夾鍊袋包裝儲藏四週之樣品。

In the domestic coffee bean sample, the higher roasting terminal temperature, the higher pH value, and the content of organic acid will drop with rising of temperature. The content of total phenol will drop with rising of temperature too. In color, the higher roasting terminal temperature, the lower L value is, but the a value and b value are getting higher. But the roasting terminal temperature exceeds more than 210℃, then a value and b value are affected by temperature and will go down. Regard 210℃ as the roasting terminal temperature, the content of caffeine is highest in coffee. In organic acid the content of quinic acid is most high, the content drops as roasting temperature is rising, and formic acid and fumaric acid content are low. During storing, no matter which kind of roasting terminal temperature, the pH value and color of sample all there is not obvious difference, the content of caffeine and total phenol will rise. It is not being obvious that the content of oxalic acid and malic get change during storing, the content of quinic acid and citric acid will rise slightly during storing. Compare with the import coffee beans, under the same roasting terminal temperature,the pH value, content of total phenol, a value, b value, content of caffeine and aroma compounds of domestic beans are relatively low, L value does not have obvious difference. When domestic and import raw coffee bean with pyrolysis at 230℃ and 250℃ for two minutes, the aroma compounds of the domestic raw coffee bean is less in total amount, but the composition with lower for polarity composition, it is still unable to represent all coffee flavor. Six organic acids in where kind roasting terminal temperature, the content of organic acid in domestic coffee bean is most high. The domestic coffee after different roasting terminal temperature, then insert a bag of packaging to store 4 weeks with vaccum packaging and LDPE zip gag, have lower total phenol and higher pH value with the sample of the vacuum then packing with the LDPE zip bag, but the two difference is not obvious, and the organic acid part has trend similar to pH value. The domestic coffee bean of packing with the vacuum bag regards 210℃ as the terminal temperature, the content of caffeine is obviously lower than packing with the LDPE zip bag when storing for 4 weeks.