Improving Heat Transfer Coefficient During Double-sided Meat Frying

Improving the energy efficiency of technological processes and equipment for heat treatment of meat and meat products is a relevant scientific task. A prerequisite for the development of new energy and resource-saving equipment for frying meat is the study of the mechanism of heat transfer in the surface layers of the product.The aim of the work was to determine the effect of the value of the logarithmic mean temperature difference (LMTD) on the value of the heat transfer coefficient k during ouble-sided frying of organic meat products by the physical and electrophysical methods.The study has proved that the LMTD between the frying surface temperature and the temperature of liquid on the capillary meniscus surface depend on the frying surface temperature. An increase in the frying surface temperature from 393 K to 423 K reduces the LMTD between the frying surface temperature and the temperature of liquid on the meniscus surface from 10 K to 6 K. The specified method of calculating the coefficient of heat transfer through vapor layers takes into account the change in the contact area of the meniscus liquid with the frying surface during evaporation and the area of the meniscus surface in the vapor condensation during double-sided frying of pork under pressure. The study has proved the dependence of the heat transfer coefficient on the LMTD between the temperature of the frying surface and the temperature of liquid on the meniscus surface. The calculated actual coefficient of heat transfer from the frying surface to the product is k423=3800 W/(m2 K) for the LMTD =10 K and k393=3800 W/(m2 K) at K.The theoretically substantiated duration of double-sided frying of organic meat under compression is completely identical to the real one

Determining the Content of Macronutrients in Berry Sauces Using A Method of IR-spectroscopy

This paper has substantiated the possibility of using an IR spectroscopy method to study patterns in the chemical composition of wild and cultivated raw materials with the addition of algae as iodine-containing supplements.It has been found that the IR spectra of sauces based on the mashed blueberry and sea buckthorn or cranberry with or without algae demonstrate a set of absorption bands attributed to the respective types of oscillations. The valence fluctuations in the hydroxyl groups in the molecules of organic acids, carbohydrates, flavonoids are observed at 3,365 cm -1 to 3,400 cm -1 ν(ОН). The bands of valence and deformation fluctuations of the ‒CH double bond of polyunsaturated fatty acids manifest themselves in the range of 3,005 cm-1 and722 cm-1. The bands of 2,925 cm-1, 2,855 cm-1 belong to the asymmetric and symmetric valence oscillations of the n(С–Н) carbon skeleton in -CH2-. The presence of the carboxylic, amino-, and fatty acids is indicated by the following absorption bands: 1,746 cm-1 ‒ ν (C=O) valence fluctuations in the protonated carboxyl group ‒COOH; 1,545 cm–1 ‒ νas(C=O; 1,415 cm–1 ‒ νs(C=O) ‒ the asymmetric and symmetric valence fluctuations of the СОО-groups; and 1,240 cm–1 ‒ the valence fluctuations of ν(C‒O). The presence of flavonoids is confirmed by the presence of bands at 1,380 cm-1 and 1,050 cm-1 ‒ the deformation δ(O‒H) and symmetrical fluctuations of O‒H groups. The fluctuations of pyranose cycles of pectins are manifested in the range of 1,163 cm– 1.It is noted that the composition of berry raw materials and sauces include polyunsaturated fatty acids, anthocyanins, flavonoids, organic acids, and pectin substances.An analysis of the IR spectra of berry sauce samples with the addition of algae has shown that the use of these additives in sauce technologies ensures a significant increase in the content of the physiological and functional ingredients and improves the hydrophobic properties of the raw material