Influence of Baking Degree on the Content of Chlorogenic Acid in Coffee by High Performance Liquid Chromatography

Abstract

The effect of baking degree on the change of seven chlorogenic acid compounds in 10 different origins (origin 1: Yunnan, origin 2: Africa and America) of Cardim coffee. The content of chlorogenic acid, neochlorogenic acid, cryptochlorogenic acid, isochlorogenic acid A, isochlorogenic acid B, isochlorogenic acid C and 5-ferulicquinic acid in green coffee and baked coffee were determined by high performance liquid chromategraphy (HPLC). The optimum extraction conditions of seven chlorogenic acid compounds were optimized by response surface methodology. 100 mL 0.1% phosphoric acid solution was extracted in water bath for 30 min, and the calibration curves of the seven chlorogenic acid compounds showed good linearity with correlation coefficients of above 0.999 4 in the range of 2~150 mg/L. Limit of the detection (LOD) and the limit of the quantitative (LOQ) were 0.005~0.5 mg/g and 0.02~2 mg/g respectively. The content of chlorogenic acid in green coffee beans was the highest, followed by 5-ferulicquinic acid. With the increase of baking degree, the content of chlorogenic acid and 5-ferulicquinic acid decreased significantly (P<0.05). The content of neochlorogenic acid and cryptochlorogenic acid increased first and then decreased. The degradation rate of isochlorogenic acid A was significantly higher than that of isochlorogenic acid B and isochlorogenic acid C. The degradation rate of chlorogenic acid and 5-ferulicquinic acid was relatively stable compared with the other six kinds of chlorogenic acid. Through the study of the content changes of seven kinds of chlorogenic acid compounds under different baking degrees can further evaluate the efficacy of chlorogenic acids in coffee, and provide a reference basis for the quality control of coffee baking.

Keywords

• coffee
• chlorogenic acid content
• baking degree
• degradation; high performance liquid chromatography