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The content ratio of whey proteins to casein can serve as an indicator of milk quality as well as criterion for the presence of milk proteins adulteration, if it exceeds 0.25. The actual task is to produce an effective and portable sensor for the named ratio. The applicability of an inexpensive portable near infrared spectrometer for the specified task was tested in this work. The streams of backscattering and transmission light in the samples of the restored milk were acquired in the form of optical density spectra for a wavelength range of 800-1065 nm using a new two-channel CCD spectrometer. It was calibrated on the content of fat, casein and whey proteins using partial least squares regression. Another objective was to develop a cost-effective way to obtain a set of reference samples with various concentrations of three components that are needed to create the calibration models or to test them. Testing the calibration designed for the measurement of fat, casein and whey proteins in drinking milk showed root mean squared errors of prediction of 0.09% wt, 0.12% wt and 0.06% wt, and correlation coefficients of 0.90, 0.82 and 0.89, respectively. The value of the 95th percentile for the ratio of whey proteins to casein was found to be ± 0.06, which is sufficiently low for practical use of the method. A comparison of models, one of which was built using the proposed "custom" set of 35 samples and the other which was based on a random set of 81 samples, showed similar acceptable results. Thus, the proposed method is suitable for cost reduction without loss of calibration quality.

Several partial least squares (PLS) calibration models were performed on spectra of standards of restored milk measured with two different types of near infrared spectrophotometers (800-1080 nm); the most reliable instrument was chosen using a self-made PLS program, ISCAP, the efficiency of which was evaluated with the Quant2 OPUS program. Then ISCAP was applied to develop and test a method of moisture prediction in milk powder based on diffuse reflection spectra received in a NIR spectrometer (1100-1700 nm) equipped with a remote fibre-optic probe The reference moisture was determined by thermo-gravimetric analysis.

Circular dichroism (CD) and absorption spectra of toluene solutions of crude oils, collected from two different reservoirs, have been measured in the spectral range, where the optical activity of crude oil solutions is due to the aggregation of asphaltene molecules and for asphaltene concentrations up to values over the critical micelle concentration (cmc). Concentration dependences of CD and the absorption signal in the maximum of the registered CD band (410 nm) in the range of low asphaltene concentrations are described by linear functions. Micelle formation of asphaltenes in crude oil solutions leads to a sharp increase of the CD signal and a violation of the linear concentration dependence of the absorption signal. A further increase of the asphaltene concentration is accompanied by saturation of the CD signal, which is possibly due to the formation of a stable phase by micelles in solution.