METHOD OF DETERMINING CRYOSCOPIC TEMPERATURE AND WATER ACTIVITY IN FOOD PRODUCTS Russian patent published in 2011 - IPC G01N33/02 

FIELD: physics.

SUBSTANCE: thermoelectric sensor is placed at the centre of a sample and the temperature value is monitored in time during the cooling-freezing process. A microprocessor based on a mathematical algorithm on cryoscopic temperature of food products during the cooling-freezing process determines water activity via numerical differentiation of the function/relationship of the time instant at which the current temperature value of the product changes with discreteness of ±0.1°C, depending on the current temperature of the product. The time instant of change in the discrete temperature value at the centre of the analysed sample is measured with accuracy of up to ±0.01 seconds or higher while measuring duration of the cooling-freezing process of the product. The current temperature value of the analysed sample is measured with resolution of ±0.1°C and accuracy of up ±(0.1-0.2)°C. In other words, the thermal image of cooling-freezing of the analysed sample of the product is captured in real time.

EFFECT: high accuracy with higher intensity of the cooling-freezing process of the analysed sample while simultaneously decreasing its mass for measurement.

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