Prediction Model of Moisture , Fat, and Free Fatty Acid Content of Physic Nut (Jatropha curcas L.)

Artikel Jarak Pagar Berita Perkebunan

ESTATE CROPS NEWS – Physic nut is a potential source of biodiesel. It is high in fat content, above 40% and has not been usesed for other purposes. Moisture, free fatty acid, and fat content are the chemical compounds and determinant factor for physic nut seed quality. The objective of this study was to develop a method to predict chemical composition of physic nut by NIR spectroscopy and PLS calibration. The study was conducted using three provenances of physic nut, i.e. IP-3A, IP-3M, and IP-3P, with 85 samples each.

The wavelengths of near infrared reflectance ranged from 1000 to 2500 nm, and measured by NIR Flex Solids Petri Apparatus. Approximately ⅔ of total samples were used for developing calibration equation, while ⅓ of total samples for performing validation. Pre-treatment of spectrum data was done by applying normalization, first derivative of Savitzky–Golay 9 points, and as well as their combination. The results showed that NIR spectroscopy performed acceptable prediction for moisture and fat content.

Correlation coefficients (r) between the reference method and NIR prediction were 0.96 for moisture content, 0.92 for fat content, and 0.89 for FFA and the consistency of the model were 94.85% for moisture content, 82.56% for fat, and 87.80% for FFA. Prediction of coefficient of variability (PCV) of the three models ≤10 % shows that the models are reliable. Ratio of standard error prediction to deviation (RPD) for moisture content has the potential to be used for screening (RPD=3.30) though the fat content model has rough screening (RPD=2.06). (/Lady C.E. DH. Lengkey, I Wayan Budiastra, Kudang B. Seminar, and Nambang S. Purwoko)

Key words: NIR, physic nut, moisture, fat, free fatty acid contents.


Download full text: perkebunan_Jurnal-Lady.-ed-6_.pdf

Source: Jurnal Littri ICECRD Vol. 19 No. 4, 2013

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