In general, processing and manipulation with foods and food raw materials have significant influence on their physical properties. The article is focused on thermophysical parameters measurement of selected foods and food raw materials. There were examined thermal conductivity and thermal diffusivity of selected materials. For detection of thermal parameters was used instrument Isomet 2104, which principle of measurement is based on transient methods. In text are presented summary results of thermal parameters measurement for various foods and food raw materials as: granular materials -corn flour and wheat flour; fruits, vegetables and fruit products -grated apple, dried apple and apple juice; liquid materials -milk, beer etc. Measurements were performed in two temperature ranges according to the character of examined material. From graphical relations of thermophysical parameter is evident, that thermal conductivity and diffusivity increases with temperature and moisture content linearly, only for granular materials were obtained non-linear dependencies. Results shows, that foods and food raw materials have different thermal properties, which are influenced by their type, structure, chemical and physical properties. From presented results is evident, that basic thermal parameters are important for material quality detection in food industry.

Božiková M., Hlaváč P., Híreš Ľ., Hlaváčová Z., Valach M., Vozárová V., Malínek M. (2017): Temperature effect on various biooils physical parameters. Res. Agr. Eng., 63: 145-151.The article deals with thermal and rheological properties of two selected biooils (PL 64S -sample No. 1, and PL 04N -sample No. 2). For thermal parameters measurements, Hot wire method was used, for detection of rheological parameters rheometer Anton Paar MCR 102 was used and the density was measured by densimeter DM 40. For both biooil samples, two series of thermophysical parameters measurements were made. In the first series thermal conductivity and thermal diffusivity were measured at constant laboratory temperature. The second series was focused on identification of thermophysical parameters changes during temperature stabilisation. The parameters as dynamic viscosity, kinematic viscosity and density were measured in the temperature range (20-50°C). For samples with constant temperature basic statistical characteristics were calculated -standard deviation and probable error in %. For relations of thermal and rheological parameters to temperature nonlinear dependencies were obtained. The polynomial functions of the second degree were used for thermal parameters and exponential functions for rheological parameters.