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The aim of this article is to develop a method for determining the dose of radiation in the processing of chilled fish and its effect on the antioxidant activity and thermophysical characteristics of muscle tissue. Radiation processing of chilled fish was performed using a linear electron accelerator model LEA-10-10S2. The dose of radiation was determined by the method of electron-paramagnetic resonance. After being treated with ionizing radiation, the cooled fish meets the requirements of the technical regulations of TR TU 021/2011 “On food safety” and TR EAEU 040/2016 “On the safety of fish and fish products”. As a result of our research, a correlation was established between the area of the Electron Paramagnetic Resonance (EPR) signal and the absorbed dose of the radiation dose. We proved a decrease in the antioxidant activity of muscle tissue of fish with an increase in radiation dose. It is established that radiation treatment of chilled fish affects the thermophysical properties of muscle tissue.

The paper presents the study on an impact of feed additives Peak anti-stress and SPAO (SPAO-complex) with different lithium content on meat productivity and meat quality of broiler chickens. The feed additives exert a pronounced metabolic effect, have adaptogen properties and allow forming a mechanism that facilitates compensation of the expenditure of the body, which significantly increases upon stress development. It was established that the average daily gain of the broiler chickens increased by 1.8% and 4.3% on the background of using SPAO-complex and Peak anti-stress, respectively, compared to the broiler chickens that did not receive the feed additives in the daily diet. It was shown that addition of feed additives with lithium into a diet led to an improvement of the indices of broiler meat productivity and meat quality: a level of yield of the carcasses of the 1st category increased up to 56.2–79.1%, high organoleptic indices of meat were ensured, the protein content in white and red chicken meat increased and functional-technological properties of minced meat improved. The use of feed additives ensured profitability of industrial poultry production; the highest indices of profitability were established upon introduction of the feed additive Peak anti-stress into a diet — up to 8.67 rubles per each ruble of expenses. The obtained results of the study should be taken into consideration in the technological processes when raising broiler chickens.

Лазарев Владимир Александрович, доцент кафедры пищевой инженерии, кандидат технических наук, Уральский государственный экономический университет (г. Екатеринбург),

Peptides are biologically active. This quality depends on the technological modes of protein hydrolysis. The research objective was to isolate peptides from the bursa fabricii and evaluate their immunotropic effect on mice of various lines with experimental immunodeficiency and the morphofunctional state of their immunopoiesis organs, i.e., thymus and spleen. The research featured bursa fabricii hydrolysate and peptides, as well as thymus and spleen of male mice. Amine nitrogen was determined according to State Standard R 55479-2013; molecular weight of peptides was determined by gel electrophoresis. The morphometry of the thymus and spleen was calculated using VideoTesT-Morphology 5.0. The research revealed the rational modes of enzymatic hydrolysis of the bursa fabricii protein by papain with subsequent isolation of peptides by ultrafiltration. According to the content of amine nitrogen in the bursa fabricii hydrolysate, the rational concentration of the papain enzyme was 0.15%. The molecular weight of peptides after ultrafiltration of bursa fabricii hydrolysate through membranes with a 43 kDa permeability had different values and depended on the concentration of papain, hydrolysis time, and temperature. The maximal amount of 27–18 kDa peptides was isolated at 36°C (85%) when the concentration of papain was 0.15% (73%), the hydromodule was 1:3 (78%), and the hydrolysis time of the raw material was 6 h (82%). The rational technological parameters of the hydrolysis of the bursa fabricii protein were as follows: concentration of papain – 0.15%, temperature – 36°C, hydromodule – 1:3, and hydrolysis time – 6 h. In immunodeficient mice, bursal peptides prevented a decrease in total cellularity in the thymus, sustained the content of CD3+ cells, activated the maturation of T-lymphocytes and proliferation of B-lymphocytes, and reduced the immunocytotoxic effects of cyclophosphamide. The article offers a new technology for obtaining peptides with a pronounced immunotropic effect that can be used in functional food production.