Arachidonic Acid (ARA, C20:4, n-6) is an essential structural component of the central nervous system. The ARA content in brain and nerve tissue is around 40% to 50% of the polyunsaturated fatty acids (PUFA) and can even reach as high as 70% in nerve endings. It is considered an essential component in both prenatal and postnatal human development. While it can be synthesized, the process is complicated. There is a demand for ARA in the form of powdered oil because studies show that the ARA concentration in bottle-feeding infants is lower than that in breastfeeding infants. The average content of ARA in human milk is 0.5% to 0.7% and it is accepted that ARA can be used as a supplement for infant formula milk powder. Determination of ARA is usually carried out by GC, which is very time-consuming, expensive, and labor-intensive to use in an industrial setting. There is a need for a cheap, real-time method to determine ARA in powdered oil and NIR spectroscopy has been examined as a method for this purpose.
- Arachidonic Acid (ARA)
Near-Infrared Spectroscopy and Partial Least-Squares Regression for Determination of Arachidonic Acid in Powdered Oil – Yang, Nie, Li, et al., Lipids (2010) 45: 559-565
One hundred ARA powdered oil samples were prepared with different concentrations as weight percentages. Spray drying was used to vary the concentration from 10% to 34%. Absorbance spectra were collected using an FT-NIR spectrometer from 10000 cm-1 to 4000 cm-1 with 16 cm-1 resolution and sixty-four scans per average. Four spectra were collected for each sample and averaged into one spectrum which were used for the data analysis. GC was used as the reference method to determine ARA concentration in the samples.
|ARA||R2 = 0.965|
Various spectra pretreatments and selected wavelength ranges were used for model parameters and the best results gave a correlation coefficient of 0.965. A validation set of samples showed a good comparison between values predicted by the NIR calibration model and the GC reference method. The result that NIR spectroscopy can be applied with a calibration model to determine the ARA content in powdered oil.
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