Influence of roasting time and extraction conditions on quantity of chlorogenic acid in coffee

Abstract

The HPLC method is now commonly used for fractional determination of chlorogenic acid (Chl). We determined the quantity of Chl (5-CQA+3-CQA) contained in raw coffee beans, and examined the influence of different roasting times and extraction conditions (temperature, device, water). The results were as follows: (1) Raw coffee beans contained 4.5 to 6.0% of Chl. This Chl was reduced by roasting, that is, about 60% of Chl was lost by mild roasting, 60 to 70% by moderate roasting, 70 to 80% by moderate to strong roasting, and 90 to 99% by strong roasting. (2) The influence of temperature on the extraction of Chl was slight, but the quantity of Chl extracted tended to be slightly higher at 95.DEG.C., followed in a descending order by 90.DEG.C. and 85.DEG.C.. (3) The quantities of Chl extracted by a spirit lamp siphon and paper drip were the same, while that extracted by an electric coffee maker was smaller. (4) The quantities of Chl extracted with distilled water and soft water were the same, but that extracted with hard water was smaller.