| 摘要 |
FIELD: measurement equipment.SUBSTANCE: they measure specific active electric conductivity of vegetable oil or melted fat at various frequencies of electromagnetic oscillations and different temperatures. To monitor quality (safety), they take a sample of investigated vegetable oil or fat, the sample is divided into two parts, one of which is exposed to oxidation on air at temperatures of 100?110°C to peroxide value of 10-12 meq/kg of active oxygen, the peroxide value of oil or fat is determined by standard methods. Then they prepare a calibration sample of vegetable oil or melted fat with content of peroxide compounds that is maximum permissible for food oil or fat (10 meq of active oxygen/kg), mixing at a certain ratio of weight the initial and oxidised sample of oil or fat, they measure in the produced calibration sample in the frequency range from 1 to 200 kHz the dependence of the specific active electric conductivity on frequency at two temperatures of measurement, by crossing of the specified dependences they find the characteristic frequency of electromagnetic field, at which the characteristic specific active electric conductivity does not depend on temperature of measurement, they assume that the produced values of the characteristic frequency and characteristic specific active electric conductivity are the maximum permissible normative values of the characteristic frequency and the characteristic specific active electric conductivity for this food oil or fat.EFFECT: development of an efficient method to monitor reduction in quality of vegetable oil during storage.2 cl, 3 dwg |
