Spectral analysis of edible oil mixture components especially for detecting Soya oil in olive oil

摘要

The components of edible oil mixtures are determined by irradiating a sample over a sample path length of greater than 8 mm and measuring the spectral distribution in the 800-1500 nm wavelength range. Preferred Features: The spectral distribution is measured in the 1300-1500 nm wavelength range (corresponding to the first harmonic of the O-H vibration, the combined C-H vibrations and the second harmonic of the C=O vibration), the 1150-1250 nm wavelength range (corresponding to the second harmonic of the O-H vibration, especially for detecting Soya oil addition) or the 800-1100 nm wavelength range (corresponding to the third harmonic of the C-H vibration). The spectral distribution may be measured continuously using a grating or prism or spectral values may be measured at points using individual filters. The spectral distribution may be measured in the extinction mode or spectral absorption or transmission values may be converted into extinction values. The spectral distribution can be determined by comparison of spectra with and without a sample.