The effect of ultrasound on the feed mixture of sunflower cake and whey

Abstract

At present, secondary products of the main production in the form of cake, oil meal, bran and whey are widely used for feeding cattle. Despite the presence of protein, fats, carbohydrates, minerals and fiber in their composition, there is a problem of low assimilability of these nutrients. Moreover, secondary products are often unsafe in terms of microbiological parameters. To solve this problem, various physical and mechanical impacts are used. The paper presents the results of the study of an ultrasound effect on the feed mixture of sunflower cake and whey. Ultrasound is wave oscillations with frequencies higher than 20 kHz. Ultrasound waves propagate in solid, liquid and gas media, have a high mechanical energy and cause several physical, chemical and biological phenomena. When ultrasound impacts a mixture, bubbles are formed and large amounts of energy are emitted upon their collapse. This energy is expended on destruction of large particles of cake with particle sizes of 1370.8–2776.6 µm in the dry cake and up to 1.8–300.0 µm in the suspension. The overwhelming majority (60–75%) of particles have sizes of 11 to 30 µm when duration of the ultrasound treatment is 20–30 min. This can be seen in the photographs of the mixture under a microscope. With that, the homogeneous gel-like mass containing protein, fat, fiber and sugars is formed from a simple mixture of components, which significantly improves the process of assimilation of structured nutrients of cake by animals. A decrease in the protein content from 10.20% to 6.65% has been revealed in the suspension with a component ratio of 1:4 to 1:8. Temperature-time regimes for ratios of the cake/whey components have been established. The optimal temperature was 60–70°C, treatment time was 20 min. A temperature was lower in the mixture with a ratio of 1:8 for all time periods due to a decrease in viscosity of the formed suspension. Microbial inactivation occurs under the impact of ultrasound, which is important for animal health and productivity. As a result of the statistical processing of process indicators, a range was established for optimal values of variable factors at which a decrease in the microbiological contamination of the mixture takes place.