Development and validation of chromatographic methods to quantify organic compounds in green coffee (Coffea arabica) beans

Abstract

Coffee is one of the oldest and most consumed beverages. The raw material for obtaining a good quality coffee drink is the grain. Bioactive compounds and organic acids in coffee beans are reflections of a series of attributes that, together, confer to the coffee peculiar flavor and aroma. This study aimed to identify trigonelline, chlorogenic acid, caffeine and organic acids in green coffee beans, and to validate the chromatographic method using High-Performance Liquid Chromatography (HPLC). Coffea arabica green coffee beans were used in this experiment. Trigonelline, chlorogenic acid, caffeine, and organic acids were identified and quantified by HPLC. Selectivity, linearity, limit of detection, limit of quantification, precision, and accuracy were used to validate the methods. Three bioactive compounds (trigonelline, chlorogenic acid, and caffeine) and seven organic acids (oxalic, citric, malic, quinic, succinic, lactic, and acetic acids) were quantified in the samples. The mean values for trigonelline, chlorogenic acid (5-ACQ), and caffeine ranged from 1.28 to 1.66, 3.47 to 4.73 and 1.26 to 1.59 g 100g-1, respectively. The values of organic acids, as well as the phenolic compounds, agree with those reported by the literature for green coffee beans of C. arabica. The validation parameters allowed the method to be considered linear, exact, and precise. Therefore, it resulted in a method reliable for studies of the composition of food matrix or quality control of green coffee beans.