MONITORING ON PLANT LEAF WATER POTENTIAL USING NIR SPECTROSCOPY FOR WATER STRESS MANAGEMENT

The performance of the calibration model with temperature compensation for on-plant leaf water potential (LWP) determination in tomato plants was evaluated. During a cycle of water stress, the on-plant LWP measurement was conducted. The result showed that the LWP values under water stress and recovery from water stress could be monitored well. It showed that a real time monitoring of the LWP values using NIR spectroscopy could be possible.   Keywords: water stress, real time monitoring of leaf water potential, NIR spectroscopy, plant response-base

Penentuan Kandungan Padatan Terlarut Buah Jeruk BW secara Tidak Merusak Menggunakan Near Infrared Spectroscopy

Buah jeruk BW sangat terkenal di Provinsi Lampung. Untuk mengoptimalkan sistem pengkelasan buah jeruk BW diperlukan sebuah metode yang dapat mengukur kandungan padatan terlarut (KPT) buah jeruk BW secara tidak merusak produk. Pada penelitian ini, dilakukan pemeriksaan terhadap potensi metode near infrared (NIR) spectroscopy pada pengukuran KPT buah jeruk BW secara tidak merusak. Sebanyak 86 sampel, masing-masing 43 buah sampel untuk membangun model kalibrasi dan uji validasi digunakan pada penelitian ini. Spektra buah jeruk diambil dengan menggunakan spectrometer portable yang beroperasi pada panjang gelombang 300-1100 nm. Spektra diambil pada dua posisi yang berbeda pada teknik diffuse reflectance. Unscrambler digunakan untuk menginvestigasi hubungan antara spektra dan KPT buah jeruk BW dengan membangun model kalibrasi. Hasil penelitian ini menunjukkan model kalibrasi terbaik diperoleh pada smoothing spektra pada panjang gelombang 700-990 nm dengan R2=0.92 dan SEC=0.36. Validasi model menunjukkan model kalibrasi memiliki nilai bias dan SEP yang kecil. Dengan menggunakan tingkat kepercayaan 95%, uji t-test menunjukkan tidak terdapat perbedaan yang nyata antara KPT yang diukur menggunakan refraktometer dan KPT yang diprediksi oleh NIR spectroscopy

PENGGUNAAN METODE SOFT INDEPENDENT MODELLING OF CLASS ANALOGY DAN UV-VIS SPECTROSCOPY UNTUK MEMBEDAKAN KOPI BUBUK ROBUSTA ASAL JAWA DAN SUMATERA SECARA CEPAT

Penelitian ini merupakan aplikasi penggunaan metode UV-VIS spectroscopy dan SIMCA untuk membedakan kopi bubuk robusta asal Sumatera dan Jawa. Pengambilan spektra sampel larutan kopi yang sudah disaring dan diencerkan, dilakukan dengan menggunakan UV-VIS spectrometer (Genesysâ„¢ 10S UV-Vis, Thermo Scientific, USA). Model SIMCA dibangun untuk masing-masing kelas yaitu model SIMCA kopi robusta Sumatera dan model SIMCA kopi robusta Jawa. Hasil prediksi menunjukkan bahwa seluruh sampel prediksi berhasil dikelompokkan secara benar sesuai dengan kelasnya masing-masing menggunakan model SIMCA yang dibangun, kecuali sampel S14aPA yang gagal dikelompokkan sebagai kopi robusta Sumatera. Berdasarkan hasil analisis plot discriminant power diperoleh kesimpulan bahwa secara umum kontribusi panjang gelombang antara 200–350 nm lebih tinggi dibandingkan dengan panjang gelombang 350–600 nm. Beberapa panjang gelombang dengan kontribusi sangat tinggi (nilai discriminant power tinggi) dan terlihat sebagai puncak pada plot adalah 245 nm, 253 nm, 264 nm, 316 nm dan 327 nm.Â

PENDUGAAN KANDUNGAN PADATAN TERLARUT BUAH SAWO MENGGUNAKAN NIR SPECTROSCOPY

Penelitian ini ditujukan untuk mengevaluasi penggunaan NIR spectroscopy dalam proses pendugaan kandungan padatan terlarut (KPT) buah sawo dengan cara tidak merusak bahan. Pada penelitian ini dilakukan investigasi hubungan antara spektra NIR yang diambil tanpa merusak buah sawo dan KPT buah sawo. Sebanyak 110 buah sawo (Achras zapota L) digunakan untuk penelitian ini yang terbagi atas 55 sampel untuk pengembangan persamaan kalibrasi dan 55 sampel untuk uji validasi. Spektra untuk setiap sampel diambil menggunakan VISNIR USB4000 spektrometer dengan teknik absorbance pada dua titik berbeda. KPT buah sawo diukur menggunakan digital refraktometer. Persamaan kalibrasi dibangun dengan menggunakan teknik regresi The Partial Least Squares (PLS). Persamaan kalibrasi dapat digunakan untuk menduga kandungan padatan terlarut buah sawo dengan koefisien korelasi (r) antara nilai KPT aktual dan prediksi sebesar 0,92, standard error of prediction (SEP) sebesar 1,17, dan bias sebesar 0,08. Persamaan kalibrasi ini juga menghasilkan nilai RPD yang tinggi yaitu sebesar 2,35. Dapat disimpulkan bahwa metode NIR spectroscopy telah berhasil mengukur KPT buah sawo dengan tanpa merusak bahan yang diuji.Kata kunci: NIR spectroscopy, kandungan padatan terlarut, teknik absorbance, persamaan kalibrasi, standar kesalahan pendugaa

PENENTUAN KEASAMAN BUAH NENAS VARIETAS CAYENNE SECARA TIDAK MERUSAK MENGGUNAKAN SHORT WAVELENGTH NEAR INFRARED (SW-NIR) SPECTROSCOPY

The acidity of pineapple fruit is one of the most important quality parameter determining the consumer acceptance. The objective of this research was to establish a nondestructive determination of acidity in cayenne pineapple fruit using short wavelength near infrared (SW-NIR) spectroscopy. In this research, a number of 124 samples, consisting of 64 samples for calibration and 60 samples for validation sample set were used, respectively. The spectra of pineapples were acquired at one position for each sample in absorbance mode using a portable spectrometer operated at 300-1100 nm. The acidity of pineapples was measured using titration method. Using the Unscrambler, statistical software for multivariate calibration, a correlation between the spectra and the acidity of pineapples will be investigated. Then, a calibration model for determining the acidity of pineapples will be developed. The result showed that the best calibration model was identified for second derivative spectra in the wavelength range of 700-970 nm with R2 = 0.95. Standard error of prediction (SEP) = 0.048 and standard error of calibration (SEC) = 0.024. The validation result showed that its calibration model had low bias. By a 95% confidence t-test there were no significance differences between the acidity measured by the titration method and that predicted by SW-NIR spectroscopy. Keywords:    pineapple, absorbance mode, acidity, near infrared spectroscopy, calibration mode

PENENTUAN BAHAN KERING BUAH SAWO SECARA TIDAK MERUSAK MENGGUNAKAN NIR SPECTROSCOPY

This work was conducted to develop a new measuring system for nondestructive dry matter prediction in sawo fruit using short wavelength near infrared (SW-NIR) spectroscopy. In this research, a number of 100 sawo fruits were used as samples. Spectra were acquired using a portable spectrometer (VIS-NIR USB4000, The Ocean Optics, USA) with 100 ms integration time and 50 scans for number of scanning. Dry matter was measured using oven drying. The calibration and validation model was developed using the partial least squares (PLS) regression method. The result showed that the best calibration model could be developed for original spectra in the wavelength range of  700-990 nm with F= 8, r = 0.92, SEC = 0.68 and  SEP = 0.86. Keywords:   Absorbance mode, dry matter, nondestructive method, sawo fruit, SW-NIR spectroscopy

Penentuan Kandungan Padatan Terlarut Buah Jeruk BW Secara Tidak Merusak Menggunakan Near Infrared Spectroscopy

Oranges Citrus sp var. chokun BW are very famous in Lampung Province. To optimize the grading  system of these oraanges, a nondestructive method to measure the soluble solids content (SSC) was needed. In this study, a nondestructive method using near infrared (NIR) spectroscopy for determining the SSC of fresh oranges was investigated. A number of 86 samples, 43 samples for both calibration and validation sample set, were used respectively. The spectra of oranges were acquired at two positions for each sample in diffuse reflectance technique using a portable spectrometer operated at 300-1100 nm. The SSC of oranges were measured using the refractometer. Using the Unscrambler, statistical software for multivariate calibration, a correlation between the spectra and the SSC of oranges was investigated. Then, a calibration model for determining  the SSC of oranges was developed. The result showed that the best calibration model was identified for smoothing spectra in the wavelength range of 700-990 nm with R2=0.92 and SEC=0.36. The validation result showed that its calibration model had low bias and low SEP. By a 95% confidence t-test there were no significance differences between the SSC measured by the refraktometer and that predicted by NIR spectroscopy.ABSTRAKBuah jeruk BW sangat terkenal di Provinsi  Lampung. Untuk mengoptimalkan sistem pengkelasan buah jeruk BW diperlukan sebuah metode yang dapat mengukur kandungan padatan terlarut (KPT) buah jeruk BW secara tidak merusak produk. Pada penelitian ini, dilakukan pemeriksaan terhadap potensi metode near infrared (NIR) spectroscopy pada pengukuran KPT buah jeruk BW secara tidak merusak. Sebanyak 86 sampel, masing-masing 43 buah sampel untuk membangun model kalibrasi  dan uji validasi digunakan pada penelitian ini. Spektra buah jeruk diambil dengan menggunakan spectrometer portable yang beroperasi pada panjang gelombang 300-1100 nm. Spektra diambil pada dua posisi yang berbeda pada teknik diffuse reflectance. Unscrambler digunakan untuk menginvestigasi hubungan antara spektra dan KPT buah jeruk BW dengan membangun model kalibrasi.  Hasil penelitian ini menunjukkan model kalibrasi terbaik diperoleh pada smoothing spektra pada panjang gelombang 700-990 nm dengan R2=0.92 dan SEC=0.36. Validasi model menunjukkan model kalibrasi memiliki nilai bias dan SEP yang kecil. Dengan menggunakan tingkat kepercayaan 95%, uji t-test menunjukkan tidak terdapat perbedaan yang nyata antara KPT yang diukur menggunakan refraktometer dan KPT yang diprediksi oleh NIR spectroscopy

Luwak Coffee Classification Using UV-Vis Spectroscopy Data: Comparison of Linear Discriminant Analysis and Support Vector Machine Methods

UV-Vis spectroscopy has been used as a promising method for coffee quality evaluation including in authentication of several high-economic coffee types. In this paper, we have compared the abilities of linear discriminant analysis (LDA) and support vector machines classification (SVMC) methods for Luwak coffee classification. UV-Vis spectral data of 50 samples of pure Luwak coffee and 50 samples of pure non-Luwak coffee were acquired using a UV-Vis spectrometer in transmittance mode. The results show that UV-Vis spectroscopy combined with LDA and SVMC was an effective method to classify Luwak and non-Luwak coffee samples. The classification result was acceptable and yielded 100% classification accuracy for both LDA and SVMC methods. However, due to the simplicity and volume of the required calculation, in this present study LDA method is superior to SVMC method

Studies on the Use of Nondestructive Method Using VIR-NIR Spectroscopy for Color Determination of Blood Oranges Flesh

In this research, the potentiality of using NIR spectroscopy and chemometrics for nondestructive determination of blood oranges flesh was investigated. Spectra of intact blood oranges fruit were acquired using a VIS-NIR MMS1 portable spectrometer in absorbance mode. The RGB of blood oranges cut flesh was measured using image processing software.  The calibration and validation models were developed using PLS regression using original spectra. The calibration results showed that the developed calibration models were promising with correlation r=0.82 for red component (R) determination and r=0.81 for green component (G) determination, respectively. Keywords: blood oranges, NIR spectroscopy, RGB color, absorbance mode, nondestructive metho

Klasifikasi Madu Berdasarkan Jenis Lebah (Apis dorsata versus Apis mellifera) Menggunakan Spektroskopi Ultraviolet dan Kemometrika

In this research, spectral data in UV region (200-400 nm) alongside PCA and SIMCA chemometrics were used to classify two types of honey obtained from different honeybees (Apis dorsata versus Apis mellifera). A total of 200 Durian monofloral honey samples from Apis dorsata and 120 samples for Longan monofloral honey from Apis mellifera were prepared. Therefore, spectral data were recorded based on the following parameters: range of acquisition 200-400 nm, transmittance mode, and interval 1 nm. In addition, the original spectra were transformed using three different algorithms: moving average smoothing with 11 segments, standard normal variate (SNV), and Savitzky-Golay 1st derivative with 11 segments and 2 ordos. The result of PCA using transformed spectra in the range of 250-400 nm explained the possibility of clearly separating Durian and Longan honey along the PC1 axis, with 98% variance, while the SIMCA showed a 100% proper classification rate for all prediction samples. In addition, several important wavelengths were identified alongside high x-loadings values at 270 and 300 nm. These results were closely related to the absorbance of important phenolic compounds in honey, including benzoic, salicylic, and aryl-alyphatic acids. The results demonstrate a probability to establish simple and low-cost honey authentication systems, using UV spectroscopy and chemometrics on free-chemical in sample preparations. Keywords: authentication, Apis dorsata, Apis mellifera, SIMCA, UV spectroscop