Prediksi Kandungan Kafein Biji Kopi Arabika Gayo dengan Near Infrared Spectroscopy

Rini Rosita, I Wayan Budiastra, Sutrisno -

Abstract


Abstract

Caffein is one of the important quality indicator of coffee. Caffein content usually determined by chemical method. Alternative method such Near Infrared Spectroscopy (NIRS) is needed to determine caffein content of coffee rapidly and nondestructively. Applications of NIRS to predict caffein content of coffee were carried out in coffee powders and liquid not in coffee beans. The objective of this study was to assess NIRS method to predict caffein content of arabica coffee bean. Coffee bean samples were placed in petri dish with 2 and 3 layers. The reflectances are measured BY FT-NIR Spectrometer in wavelengths of 1000 – 2500 nm, followed by determination of caffein content by chemical method. Some pre-processing NIRS data such as normalization between 0 and 1 (n01), first derivative of Savitzky-Golay 5 points (dg1), second derivative of Savitzky-Golay 5 points (dg2), combination n01 and dg1, combination n01 and dg2, and PLS calibration to increase accuracy of NIRS prediction. The best prediction is obtained by second derivative and 5 factors PLS with 3 layers of coffee beans with the high R = 0.97 and RPD (5.93), low of SEP and CV (0.007%, 1.76%). This study demonstrated that NIR spectroscopy had excellent potential analysis to determine caffein content of coffee beans.

Abstrak

Kafein merupakan salah satu indikator mutu terpenting dari kopi. Biasanya kandungan kafein kopi ditentukan dengan metoda kimia. Metoda alternatif seperti Near Infrared Spectroscopy (NIRS) diperlukan untuk penentuan kandungan kafein biji kopi secara cepat dan nondestruktif. Hingga saat ini, aplikasi NIRS untuk penentuan kandungan kafein dilakukan pada kopi bubuk atau kopi cair dan bukan pada biji kopi. Tujuan penelitian ini adalah mengkaji metoda NIRS untuk memprediksi kandungan kafein biji kopi arabika gayo. Biji kopi diletakkan dalam cawan petri dengan 2 dan 3 tumpukan. Reflektan biji kopi diukur menggunakan FT-NIR Spectrometer pada panjang gelombang 1000 – 2500 nm. Dilanjutkan dengan penentuan kandungan kafein kopi dengan metode kimia. Beberapa pra-pengolahan data NIRS seperti normalisasi antara 0 – 1 (n01), derivatif pertama Savitzky-Golay 5 point (dg1), derivatif kedua SavitzkyGolay 5 point (dg2), kombinasi n01 dan dg1, dan kombinasi n02 dan dg2 serta kalibrasi dengan PLS dilakukan untuk meningkatkan akurasi metoda NIRS. Prediksi NIRS terbaik diperoleh dengan pra-PLS dengan 3 tumpukan dengan koefisien korelasi (R = 0.97) dan RPD (5.93) yang tinggi, SEP dan CV yang rendah (0.007%, 1.76%). Penelitian ini membuktikan metode NIRS berpotensi untuk analisis kandungan kafein biji kopi.


Keywords


Coffee bean, caffein, second derivative Savitzky-Golay 5 points, NIRS, PLS

Full Text:

PDF

References


[BPS] Badan Pusat Statistik. 2014. Statistik Ekspor Impor Komoditas Pertanian 2001-2013. J Statistik Ekspor Impor Komoditas Pertanian

-9578.

Alessandrini, L., S. Romani, G. Pinnavaia and M.D. Rosa. 2008. Near infrared spectroscopy: An analytical tool to predict coffee roasting degree. J Analytica Chimica Acta. 625: 95–102.

Andasuryani, Y.A. Purwanto, IW. Budiastra and K. Syamsu. 2013. Determination of catechin as main bioactive component of gambir (Uncaria gambir Roxb) by FT-NIR Spectroscopy. J Medicinal Plant Research 7(41): 3076-308.

Burdan, F. 2015. Content of caffeine in coffee and in nutritional and medical products. J Phytochemistrv 31: 1271-1272.

Chen, H., Q. Song, G. Tang, Q. Feng and K. Lin. 2013. The combined optimization of SavitzkyGolay smoothing and multiplicative scatter

correction for FT-NIR PLS models. ISRN Spectroscopy: 1-9.

Cozzolino, D., W.U. Cynkar, N. Shah, R.G. Dambergs and P.A. Smith. 2009. A brief introduction to multivariate methods in grape and wine analysis. International J Wine Research 1: 123-130.

Downey, G., E. Sheehan, C. Delahunty, D. O'Callaghan, T. Guinee and V. Howard. 2005. Prediction of maturity and sensory attributes

of Cheddar cheese using near-infrared spectroscopy, J Dairy 15: 701-709.

Eriksson, L., E. Johansson, N. Kettaneh-Wold, C. Wikstrom and S. Wold. 2000. Design of Experiments: Principles and Applications. Umea,

Sweden: Umetrics [AB].

Hecimovic, I., A. Belscak, D. Horzic and D. Komes. 2011. Comperative study of polyphenols and caffeine in different coffee varieties affected by

the degree of roasting. J food chemistry 129: 991-1000.

Hifnalisa dan A. Karim. 2008. Studi awal varietas biji kopi arabika berdasarkan ketinggian tempat di dataran tinggi Gayo. J Agrista 162-172.

Hruschka, W.R. 1990. Data analysis: wavelength selection methods. In P. Williams and K. Norris (eds.) Near-Infrared technology in the agricultural and food industries. St. Paul, MN: American Association of Cereal Chem-ists Inc.: 35-55.

Huck, C.W., W. Guggenbichler and G.K. Bonn. 2005. Analysis of caffeine, theobromine and theophylline in coffee by near infrared spectroscopy (NIRS) compared to highperformance liquid chromatography (HPLC)

coupled to mass spectrometry. J Analytica Chimica Acta 538 (2005) 195–203.

Lengkey, L.C.Ch., IW. Budiastra, K.B. Seminar and B.S. Purwoko. 2013. Determination of Chemical Properties in Jatropha Curcas L. Seed IP-3P by Partial Least-Squares Regression and NearInfrared Reflectance Spectroscopy. J Agriculture Innovations and Research 2: 2319-1473.

Mattjik, A.S. dan IS. Made. 2006. Perancangan Percobaan dengan Aplikasi SAS dan MINITAB. IPB Press, Bogor[ID].

Maramis, R.K., G. Citraningtyas dan F. Wehantouw. 2013. Analisis Kafein dalam Kopi Bubuk di Kota Manado meggunakan Spektrofotometri UV-Vis. J Ilmiah Farmasi – UNSRAT 2: 04.

Mouazen, A.M., W. Saeys, J. Xing, J. De Baerdemaeker and H. Ramon. 2005. Near infrared spectroscopy for agricultural materials:

an instrument comparison. J Near Infrared Spectroscopy 13: 87-97.

Nicolai, B.M., K. Beullens, E. Bobelyn, A. Peirs, W. Saeys, K.I. Theron and J. Lammertyn. 2007. Nondestructive measurement of fruit and

vegetable quality by means of NIR spectroscopy: areview. Postharvest Biology and Technology 46: 99-118.

Pizarro, C., I. Esteban-Diez, A.J. Nistal and J.M. González-Sáiz. 2004. Influence of data preprocessing on the quantitative determination

of the ash content and lipids in roasted coffee by near infrared spectroscopy. J Analytica Chimica Acta 509: 217–227.

Reh, C.T., A. Gerber, J. Prodolliet and G. Vuataz. 2006. Water content determination in green coffee method comparison to study specificity

and accuracy. J Food Chemistry 96: 423–430.

Rodrigo, J.S., M.C. Sarraguça, O.S.S. Rangel António and A. Lopes João. 2012. Evaluation of green coffee beans quality using near infrared

spectroscopy: a quantitative approach. J Food Chemistry 135: 1828–1835.

Swierenga, H., A.P. de Weijer, R.J. van Wijk and L.M.C. Buydens. 1999. Strategy for constructing robust multivariate calibration models. J

Chemometrics and Intel-ligent Laboratory Systems 49: 1-17.

Williams, P. and K. Norris. 1990. Near-infrared technology in the agricultural and food industries. American As-sociation of cereal chemical, Inc. St. Paul. USA[US]: 146.

Walpole, R.E. 1995. Pengantar Statistika Edisi Ke-3. PT Gramedia, Jakarta [ID].

Zhang, X., W. Li, B. Yin, P. Chen, K. Declan, X. Wang, K. Zheng and Y. Du. 2013. Improvement of near infrared spectroscopic (NIRS) analysis

of caffeine in roasted arabica coffee by variable selection method of stability competitive adaptive reweighted sampling (SCARS). J Elsevier Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 114: 350–356.




Copyright (c) 2016 Jurnal Keteknikan Pertanian

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Alamat Redaksi: 
Jurnal Keteknikan Pertanian, Departemen Teknik Mesin dan Biosistem, Institut Pertanian Bogor, Kampus IPB Darmaga, Bogor 16680. Telp. 0251-8623026; Fax: 0251-8623026; Email: jurnaltep@yahoo.com  website: http://journal.ipb.ac.id/index.php/jtep 

 

This journal is published under the terms of Creative Commons Attribution 4.0 International License.