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The article presents the results of biotesting food protein gels and ready-to-eat gel-based fish products. Axenic culture of ciliates Tetrahymena pyriformis was used as an indicator organism, which are known to have similar metabolic processes with cells of higher organisms. The ability of unicells to use intact proteins as a nutrient substrate determines their use in assessing the biological value of food. In the course of research, using a test-organism T. pyriformis , the rational temperature of heat treatment of food protein gel was equal to 85°C. Such temperature provides high rates of the ciliates population in the cultivating environment, the number of cells in which was counted and amounted to 2.3 × 106 cells/ml. In addition, the finished product has a high bioavailability ratio of 160% relative to the non-thermoprocessed product (i.e., raw). Biotesting ready-to-eat fish products enriched with protein from different fish in the Pacific basin made it possible to carry out a comparative characteristic of their biological value. It was determined that ready-to-eat fish products from giant grenadier, in which pollock served as enricher, have the highest index of the relative biological value - 101.4%, which is confirmed by studying the protein content of the products. At the same time, gels from the muscular tissue of giant grenadier without protein enrichers possess high indices of bioavailability and effectiveness of the protein when compared with product samples that contain protein enricher. However, this phenomenon causes the rapid depletion of the nutrient medium after 48 hours and further death of the T. pyriformis population. Thus, biotesting using the simplest allows for a comparative assessment of ready-to-eat fish product quality by simply counting the number of ciliates by experience in culture media. A graphical analysis of the data obtained throughout the life cycle of a T. pyriformis population allows to quickly and accurately assess the viability of ciliates, the degree of assimilation of the nutrient substrate, and draw conclusions about the biological value of the product.

Application conditions of the ACTIVA® TG-TI transglutaminase combined with setting agents (gelatine and chitosans of various modifications) are substantiated for moulded food processing from waterlogged fish raw materials targeted by deep-water fishery, i.e. giant grenadier (Albatrossia pectoralis). It was shown that combining different setting agents ensures time reduction of gel formation with a minor change in their development and melting temperatures. Adding an enzyme preparation leads to the formation of thermostable gels with a 1.5-fold increased strength. When forming gels from the grenadier muscle tissue in the presence of setting agents of different concentrations, the quality of soluble muscle proteins reduces, most prominently with gelatine and chitosan ascorbate. Physicochemical parameters of the structured gels prepared from the muscle tissue of giant grenadier (moisture retention capacity, tensile strength, water activity) and their organoleptic profiles were measured. Based on the results, we have shown that adding 3% of gela-tine, 0.06% of high-molecular chitosan and 1% of transglutaminase may be employed for processing moulded fish products. The digestibility of the protein components in obtained samples did not depend on fermentation. The overall protein deposition was between 0.38 and 0.56% of the sample mass. The total biological value of samples ranged from 78 to 134% when studying their effect on the growth of T. pyriformis testing culture.

Introduction. The research features a detailed sensory evaluation of mass fishing objects belonging to different families, namely: the Macrouridae represented by the giant grenadier (Albatrossia pectoralis), the Herrings represented by the Pacific herring (Clupea pallasii), and the Salmons represented by the Keta salmon (Oncorhynchus keta). The research objective was to study the possibility of increasing the information content of the verbal description of fish raw materials in combination with a quantitative assessment of individual sensory indicators. Research objects and methods. The paper introduces the concept of detailed verbal description of group parameters of raw and heattreated muscle tissue. The description can increase the information capacity of sensory studies. The concept of extended description of fish raw material was added to the main sensory properties that describe color, smell, taste, and consistency. They include data on the properties of local areas with subcutaneous layer, dark muscles, fat layers, etc. Such a detailed verbal description gives an in-depth view of the sensory properties, which is part of general information on the functional and technological properties of the fish and a key factor in designing new developed products. To improve the objectivity of sensory research, the authors employed the method of quantitative evaluation. Results and discussion. The results were summed up as data on the significance coefficients established by experts, ranked, and expressed as a percentage. The significance coefficient is a method of quantitative regulation of the share of each sensory indicator in the general sensory evaluation. The research showed that the greater the number of group sensory indicators that characterize the object, the smaller and more similar their coefficients of significance, which dramatically reduces application opportunities. Therefore, significance coefficient proved a convenient means of measurement and visual presentation. However, the research was limited by the experimental conditions. Conclusion. The study of the fish raw materials established, identified, and described individual sensory indicators that involved about twenty lexical units for raw material and thirty units for heat-treated muscle tissue. The individual sensory indicators characterized color, smell, and taste. They differed in the presence of several degrees of gradation and fit into a vertical three-level (sometimes two-level) classification. Group touch indicator of the consistency describes mostly single-level unit indicators with 4–6 lexical units. As a result, the detailed description of sensory properties of fish raw materials included 2–3 times more lexical units compared to the traditional description of fish raw materials in the special reference literature.