METHOD TO ANALYSE MILK AND SOUR-MILK DRINKS

摘要

FIELD: physics, measurements.;SUBSTANCE: proposed method comprises defining the availability and concentration of artificial flavoring agents and acidity of the said products using a matrix of four piezo-sensors with base frequency of oscillation of 8 to 20 MHz. First of all, the films of acetone solutions of tri-oktylfosfinoxide, di-cyclohexano-18-crown-6, 4-aminoantipyrine and adipinate polyethylene glycol are applied onto the electrode surface so that, after drying the piezo-sensors at 40 to 50°C for 15 to 20 min, the film coat weight makes 10 to 25 mcg. The dried piezo-sensors are placed inside the detection cell. Then, a sample of milk or sour-milk drink is taken to be placed into weighing bottle with polyurethane membrane on the cover and cured for 10 min. now, the syringe is used to pump out through the membrane some 3 cm³ of equilibrum gas phase of the sample to be injected into the detection cell. The piezo-sensor oscillation frequency is recorded during 1 min. Using the differential algorithm, a total analytical signal in the form of kinetic "weight aromograms" is generated , while the sample equilibrium gas phase matrix analytical signal is subtracted from analytical signals of equilibrium gas phase matrix of the samples under analysis. Geometrical characteristics of the "weight aromograms" of the analysed samples are compared to the data base proceeding from the results of analysing flavoring agent samples-standards. The availability of artificial flavouring agent and its content are estimated by the shape and area of the "weight aromograms". Note the sample acidity is defined from the maximum analytical signal of piezo-sensor with the film of acetone solution of adipinate polyethylene glycol and from the curve of dependence of the maximum analytical signal (ΔF, Hz) on the product acidity (K, °T).;EFFECT: fast analysis, accuracy of measurements, reliability of results, simple processing of results and decision-making, defining quality of products in one measurement of acidity.;3 dwg, 2 tbl, 1 ex