Prediction of Caffeine Content in Java Preanger Coffee Beans by NIR Spectroscopy Using PLS and MLR Method

2nd International Conference on Agricultural Engineering for Sustainable Agricultural Production

Budiastra, I.W.^1 ; Sutrisno, S.^1 ; Widyotomo, S.^2 ; Ayu, P.C.^1

Department of Mechanical and Biosystem Engineering, Bogor Agricultural University, Indonesia^1

Indonesian Coffee and Cocoa Research Institute, Jember, Indonesia^2

关键词: Absorption wavelengths;    Caffeine contents;    Chemical measurements;    Coffee beverages;    Destructive methods;    First derivative;    NIR spectroscopy;    Nondestructive methods;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/147/1/012004/pdf
DOI  :  10.1088/1755-1315/147/1/012004

来源: IOP

【 摘 要 】

Caffeine is one of important components in coffee that contributes to the coffee beverages flavor. Caffeine concentration in coffee bean is usually determined by chemical method which is time consuming and destructive method. A nondestructive method using NIR spectroscopy was successfully applied to determine the caffeine concentration of Arabica gayo coffee bean. In this study, NIR Spectroscopy was assessed to determine the caffeine concentration of java preanger coffee bean. A hundred samples, each consist of 96 g coffee beans were prepared for reflectance and chemical measurement. Reflectance of the sample was measured by FT-NIR spectrometer in the wavelength of 1000-2500 nm (10000-4000 cm-1) followed by determination of caffeine content using LCMS method. Calibration of NIR spectra and the caffeine content was carried out using PLS and MLR methods. Several spectra data processing was conducted to increase the accuracy of prediction. The result of the study showed that caffeine content could be determined by PLS model using 7 factors and spectra data processing of combination of the first derivative and MSC of spectra absorbance (r = 0.946; CV = 1.54 %; RPD = 2.28). A lower accuracy was obtained by MLR model consisted of three caffeine and other four absorption wavelengths (r = 0.683; CV = 3.31%; RPD = 1.18).