Comparative Study On Characteristic Components Of Coffee Beans From Different Regions And Varieties

Coffee beans are the kernels of the small evergreen coffee trees of the genus Rubiaceae.Its origin is Ethiopia in Africa.It is known as the three major beverages in the world along with tea and cocoa.The coffee beans are mainly produced in Yunnan,Hainan and Taiwan in our country.This paper explored the effects of different varieties,different producing areas and different processing methods on the content of coffee beans,and provided theoretical basis for the construction of quality standard system of coffee beans in China.In this study,a high performance liquid chromatography-mass spectrometry(HPLC-MS)method was established for the first time to detect 10 specific components of coffee beans,such as caffeic acid,chlorogenic acid,fumaric acid,gallic acid,succinic acid,anhydrous citric acid,L-malic acid,DL tartaric acid,D-(-)quinic acid and trigonelline.Arabica and Robusta coffee beans from different producing areas were selected,and five producing areas of Pu'er,Baoshan,Dehong,Dali and Lincang in Yunnan Province were selected.Three different processing methods,sun-dried,waterwashed and honey-treated,were used to study coffee beans.Combined with chemometrics analysis method,the influence of different factors on its quality index was analyzed.The content of carbohydrates and volatile substances in different varieties of green coffee beans were higher,which were higher than 183.55mg/g.The caffeine content of Robusta coffee beans was 1.65 times that of Arabica.The variable values of coffee beans from Baoshan and Dali were higher in Yunnan,Among them,samples from Baoshan contained the highest carbohydrate and volatile substances content,which were 290.95 mg/g and 212.40 mg/g,respectively.Different processing methods have great influence on the contents of caffeine,chlorogenic acid,trigonelline and volatile matter.The caffeine content of coffee beans processed by water washing method was 13.67 mg/g,which was higher than that of other processing methods.Roasted coffee beans from Italy,Kenya,Brazil,Panama,Yunnan,Hainan and Taiwan were selected and carry out component detection.Chlorogenic acid and trigonelline were the main flavor compounds in coffee beans.The content of chlorogenic acid and trigonelline in Panama was the highest,which were 20.58 mg/g and 29.26 mg/g,respectively;The chlorogenic acid content of coffee bean in Taiwan was the lowest,7.14 mg/g;The content of cucurbitacin in coffee beans from Hainan was the lowest,9.48 mg/g.Through principal component analysis and cluster analysis,it was found that the flavor content of coffee bean samples was greatly affected by the region,and the coffee bean samples from Panama had obvious uniqueness.