Akuisisi Spektrum Near Infrared Reflectance pada Biji Kakao - Zulfahrizal, Zulfahrizal; Sutrisno, Sutrisno; Seminar, Kudang B.; Munawar, Agus A. (Jurnal Tanaman Industri dan Penyegar, 2013)
Akuisisi spektrum Near Infrared Reflectance Spectroscopy (NIRS) untuk produk olahan kakao telah banyak dilakukan dalam berbagai penelitian namun untuk biji kakao utuh masih belum dilakukan. Tujuan yang ingin dicapai dalam penelitian ini adalah mengembangkan teknik akuisisi spektrum NIRS untuk mendeteksi tingkat fermentasi biji kakao dan menentukan selang panjang gelombang yang mengandung informasi kualitas biji kakao secara nondestruktif. Penelitian ini dilakukan di Pusat Penelitian Kopi dan Kakao Indonesia, Jember-Indonesia dan Georg August University of Göttingen di Göttingen-Jerman pada Juli 2012 sampai Februari 2013. Penelitian menggunakan Multiplicative Scatter Correction (MSC) dan Standard Normal Variate (SNV), Savitzky-Golay smoothing (SGs) dan derivative pertama (D1), derivative kedua (D2) sebagai metode koreksi spektrum dan Principal Component Analysis (PCA) sebagai metode pengolah data spektrum. Hasil penelitian menunjukkan bahwa akuisisi spektrum NIRS pada biji kakao tumpukan mampu menggantikan akuisisi NIRS pada biji kakao individu. NIRS juga diketahui mampu membedakan tingkat fermentasi pada biji dan bubuk kakao. Melalui studi ini ditemukan juga selang panjang gelombang yang dapat mengidentifikasikan kualitas kakao sehingga dapat digunakan untuk penelitian selanjutnya dalam pengembangan model identifikasi kualitas kakao.Kata Kunci: Biji kakao, NIRS, metode nondestruktifNear Infrared Reflectance Spectroscopy (NIRS) spectra acquisition for processed cocoa products has been widely applied in various studies. The application of this method for whole intact cocoa beans is however scarce. The objectives of this research were to develop a spectral acquisition technique of NIRS to detect fermentation level of cocoa beans and determine the wavelength range interval containing cocoa bean quality information nondestructively. This research was performed in Indonesian Coffee and Cocoa Research Institute, Jember-Indonesia for fermentation treatment and Georg-August University of Göttingen, Germany for spectra acquisition. These were conducted from July 2012 to February 2013. Multiplicative Scatter Correction (MSC), Standard Normal variate (SNV), Savitzky-Golay Smoothing (SGS) and spectra transformation into its first and second derivative (D1 and D2 respectively) were used as spectral pre-processing method whilst principal component analysis (PCA) was applied as a method of data processing. The results showed that NIRS spectrum acquisition on bulk of cocoa beans could replace NIRS acquisition on the individual beans. NIRS is able to distinguish the fermentation stages both in cocoa beans and cocoa powder. The study also found several NIR wavelength range interval associated with cocoa quality so that it can be used for further studies to develop cocoa quality attributes prediction models.