ATR-FTIR FOR CHARACTERIZING AND DIFFERENTIATING DRIED AND GROUND COFFEE CHERRY PULP OF DIFFERENT VARIETIES (Coffea Arabica L.)

ABSTRACT This study aimed to evaluate the performance of the infrared spectrum in the range of 4000−650 cm−1 for characterizing and differentiating dried and ground coffee cherry pulp of different varieties. The spectral data were subjected to first and second derivative treatments to perform the statistical analyses. Three varieties of coffee pulp were previously characterized for color, water activity, moisture, chlorogenic acids, and caffeine. The results of principal component analysis (PCA) showed that Fourier transform infrared (FTIR) spectroscopy is a viable technique for characterizing and differentiating dried and ground coffee cherry pulp among different varieties, showing the best differentiation with treatment of data from the first derivative, which was mainly associated with the caffeine content and chlorogenic acids. This study is the first investigation of FTIR spectroscopy with attenuated total reflectance for characterizing dried and ground coffee cherry pulp from coffee varieties grown in Colombia.

摘要
本研究旨在评估波数范围为4000~650 cm⁻¹的红外光谱对不同品种干燥磨碎咖啡樱桃果肉的表征与区分性能。本研究对光谱数据进行一阶、二阶导数处理以开展统计分析。研究人员已针对色泽、水分活度、水分含量、绿原酸与咖啡因三项指标，完成对三种咖啡果肉样品的表征。主成分分析（Principal Component Analysis, PCA）结果显示，傅里叶变换红外光谱（Fourier Transform Infrared Spectroscopy, FTIR）可作为有效技术实现不同品种干燥磨碎咖啡樱桃果肉的表征与区分；其中经一阶导数处理的数据展现出最优区分效果，该处理结果主要与咖啡因含量及绿原酸相关。本研究是首次采用配备衰减全反射（Attenuated Total Reflectance, ATR）附件的FTIR光谱技术，对哥伦比亚种植的不同咖啡品种所产干燥磨碎咖啡樱桃果肉开展表征研究。