Özet:

This paper reports the improved rotor-film evaporator with the lower arrangement of the separating space, the auger-type discharge of concentrated organic fruit and berry paste, and preheating the puree with secondary steam. The working surface of the evaporator is heated by a flexible film resistive electric heater of the radiating type with an insulating outer surface. Peltier elements installed in the device make it possible to provide low-voltage power for exhaust fans from the thermal secondary steam. The puree fed for processing is preheated by 8...10 °С by the heat from the concentrated product and secondary steam. For the experiment, fruit and berry blended puree from apples, quince, and black currants was used. The structural and mechanical properties of blended puree have been determined when the temperature changes within 55...75 °С, in particular, the effective viscosity varies in the range of 22...6 Pa∙s, the maximum shear stress ‒ 29...8 Pa. Effective regions in the fruit and berry puree concentration process have been established: Kmin=Vpaste/Vpuree=0.190; Kmax=Vpaste/Vpuree=0.725 When concentrating fruit and berry pastes with an initial solids content of 9...15 % to the resulting content (29...31 %), it is advisable to apply a surface load of 0.048...0.121 kg/m2s. By calculation, the reduction of the specific energy consumption for heating the volume of the product unit has been confirmed: a rotor-film evaporator – 547 kJ/kg over a period of 75 s, compared to the basic vacuum evaporator – 1,090 kJ/kg, respectively, over 1.08 hours. The results could be useful when designing evaporating equipment for rotor-film-type devices in order to concentrate various blends of fruit and berry raw materials under conditions of using the energy of secondary steam. Author Biographies Andrii Zahorulko, Kharkiv State University of Food Technology and Trade PhD, Associate Professor Department of Processes and Equipment Food and Hospitality-Restaurant Industry named after M. Belaev

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