Providing the population with high-quality food products of increased nutritional and biological value is an urgent issue of today, due to a violation of the nutritional status, and a lack of several essential nutritional factors. In this regard, the concept of creating new food products, chemically balanced, enriched with functional components, and ensuring their immutability, health safety after technological processing, as well as during storage, is becoming increasingly important (Sukhenko et al., 2017).

The current state of nutrition of the Ukrainian population requires the development and implementation of production technologies based on natural raw supplies and expected composition, for now, it is represented by products that do not meet the human needs for the key nutrition factors. In Ukraine, there is an increase in the volume of cultivation and fishing in freshwater facilities, the product range of which is limited to live and chilled fish. Organoleptic parameters of freshwater fish and their nutritional value require streamlining of technologies for its processing by combining it with vegetable raw products (Golembovskaya and Lebskaya, 2015).

Carp are the fish that are mostly grown in the water farms of Ukraine. This type of fish contains a lot of protein with all essential amino acids, biologically effective fatty acids, but the flesh of this fish has a low percent, or no dietary fiber, and lacks several trace elements essential in nutrition following the requirements of modern nutritionology concepts. Besides, freshwater fish have a low taste property, which indicates the feasibility of their improvement (Mushtruk et al., 2020a). There are aromatic root vegetables, grown in Ukraine, which are only partially used in the technology of fish products. Previous studies have found that the use of vegetable raw products in the technologies of freshwater hydrobionts, including aromatic root vegetables, facilitates the harmonization of organoleptic indicators, and obtaining food products with functional ingredients.

However, systemic studies in the activation of the maturation processes of freshwater fish in the composition of preserves have not been conducted. Thus, the development of the technology of preserves made of freshwater fish and aromatic root vegetables is an urgent issue, the solution of which will facilitate the production of high-quality and healthy biologically valuable fish products from the Ukrainian raw products and expand the range of products including freshwater fish.

The analysis of current trends in fish production technologies allows to identify the following key directions that are related to the technologies of multicomponent food products, improvement of technologies of preserves made of low maturity hydrobionts, the enrichment of the recipe composition, pretreatment of raw products in various ways, the application of physico-chemical and biotechnological techniques for the production of conventional foods made of fish such as canned food, preserves, pâté, salted, dried, culinary products and washed minced products for surimi production (Shanina et al., 2020).

The record shows that the use of enzymatic agents during fish salting makes it possible to obtain good quality products from immature fish species. It is possible to use expensive enzymatic agents in the production of fish preserves, made of plant and microbial raw supplies, for example, culture liquid H. Mediteranei to soften pollock flesh or the proteolytic enzyme preparation Sal Intersor EC for the production of fish fillet preserves.

These scientists' works highlight the fact that some marine hydrobionts contain highly active complexes of proteolytic enzymes that can be widely used. The muscle tissue of freshwater fish has a low level of activity of its proteinases, which does not allow achieving the desired degree of maturation without additional application of proteolytic enzyme preparations that intensify this process (Shanina et al., 2019).

S. L. Chernyavskaya has developed the technology of a proteolytic enzyme preparation from zebra mussel, proving the effectiveness of using Protofermol proteolytic enzyme preparation from a zebra mussel, bivalve mollusk, without preliminary separation of the flaps to intensify the maturation process of preserves made of Baltic herring pieces (Chernyavskaya et al., 2019).

Bùi Xuân Đông has developed a new range of preserves made of fillets of pond fish species, whose enzyme system of muscle tissue was activated by injecting an enzyme preparation derived from their internal organs (Bùi, 2011).

Similar studies were conducted by T. J. Park and coauthors (Park et al., 2020), which highlighted the production of proteolytic enzyme preparations from the entrails of pond fish such as carp, silver carp, grass carp, and pike. O. P. Dvorianynova, in collaboration with other scientists, obtained an enzyme complex from the muscle tissue of pond carp, and determined the proteolytic activity of the obtained enzymes (Dvoryaninova et al., 2010). Оther authors theoretically substantiated and experimentally confirmed the expediency and effectiveness of using new methods for intensifying and regulating the maturation of preserves made of poorly maturing fish species by introducing white cabbage as a source of plant proteases, and the enzyme preparation Sal Intensor EC of proteolytic action into the formulation.

T. A. Davletshyna substantiated the mechanism of the antimicrobial drug action on microorganisms, their proteolytic and lipolytic enzymes, which reduce bacterial contamination of semi-finished products and finished fish products (Davletshina et al., 2019).

Technologies for the production of non-fish preserves, namely squid and whelk ones, which are low-maturing raw products for the production of preserves, were of considerable interest, too (Saltanova and Malinovskaya, 2012). The technology of making preserves using these shellfish involves the pretreatment of raw products by blanching, or the use of gamma radiation to soften the flesh.

The effectiveness of processing fish preserves with orange juice, which helps them mature, has been highlighted. The use of orange juice as a dietary supplement provides the product with functional properties, as it enriches the preserves with biologically active substances, C, PP, B vitamins, beta-carotene, as well as potassium, calcium, iron, and selenium.

The considered fish raw products’ technologies speak for the prospects for improving the preserves technologies, as products that preserve the natural properties of raw products to a greater extent due to the absence of heat processing.

Thus, the change in the structure of fishing, the general trend of reducing the catch of conventional marine fish species, an increase in the number of freshwater fish as aquaculture objects makes it necessary to improve complex technologies for processing raw products and expand the range of freshwater fish food products. One of the promising ways to address these issues is to develop the technology of freshwater fish preserves enriched with vegetable ingredients, based on the principles of food combinatorics. The use of aromatic root vegetables is one of the priority areas of research in the future.

Previous research has shown that the use of vegetable raw materials (Rodak and Fil, 2016; Pobedash, 2020; Paska et al., 2020; Fedorova and Kuzmenko, 2015; Shubina et al., 2019; Fedorova and Dasheev, 2017; Shubina et al., 2017) and, including spicy-aromatic roots, in the technology of freshwater aquatic organisms contribute to the harmonization of organoleptic characteristics.

The results of studies of the chemical composition of carp preserves and aromatic root vegetables are shown in Table 1. It should be noted that the mineral composition of the test samples differs from that of the control sample, which is due to the content of minerals in vegetable additives (ginger, horseradish, parsley), which in combination with fish raw products enrich the preserves. If we compare with the studies (Shulgina et al., 2017; Alekseeva, 2019) of other authors who do not add vegetable raw materials, we get a much lower mineral content of an average of 1.4%.

The fatty acid composition was determined in preserves with sunflower oil and a mixture of sunflower oil and linseed oil in a ratio of 1:1. Similar studies (da Silva et al., 2019; Lansing et al., 2018; Fernandez et al., 2019; Eveleva and Cherpalova, 2019; Brazhnaya, 2016) describe similar studies, but the authors used different types of oils (sunflower and olive, soybean and sunflower, corn and others) and the ratio of oils (1:2, 1:3, 1:5 and 1:10). The fatty acid composition of preserves with sunflower oil is shown in Table 2.

According to experimental data, the content of all FA groups in the preserves studied is exceeded in all groups, but the control sample, in which the sum of saturated acids approaches the recommended amount. Among saturated acids, palmitic acid is dominant, the content of which in experimental samples with various aromatic root vegetables exceeds the control sample by 5%.

The fatty acid composition of preserves with sunflower and linseed oil is shown in Table 3.

Analyzing the data presented in Table 3, it was found that the content of saturated and monounsaturated FA compared to the recommended amount in the experimental samples is lower, but the enrichment of preserves takes place due to the high content of polyunsaturated FA, namely linoleic acid the linseed oil is rich in.

The results of indicators of biological effectiveness of lipids of preserves made of carp and aromatic raw products with sunflower oil and sunflower-and-linseed oil are shown in Table 4.

It should be particularly noted that the high content of fatty acids of the ω₃ family in the lipids of preserves, which we have found, speaks for their high biological efficiency (Mushtruk et al., 2020a; Barboza et al., 2020; Golembovskaya, 2020).

The characteristics of the effect of aromatic root vegetables on the mineral composition of preserves made of freshwater carp fish are shown in Table 5.

Based on these results, the level of all mineral elements is significantly increased in preserves with aromatic root vegetables, compared to the control sample and studies by other authors (Dementeva and Bogdanov, 2017; Petrik, 2016; Abramova and Goferber, 2017), which speaks for the expediency of adding aromatic root vegetables to this product to enrich it with essential mineral elements and obtain a healthy food product of high value.

Taking into account the different needs of a human body for minerals, we have calculated the level of macro- and microelements to meet daily needs provided that 200 grams of preserves are consumed (Figure 2).

The control sample was characterized by a lower degree of meeting the daily requirement for most trace elements, which can be explained by a less balanced mineral composition of fish raw products.

These data speak for the fact that the degree of manganese supply provided that the preserve with ginger is consumed is the highest and makes up 85% of its daily requirement, respectively. Preserves with horseradish and parsley meet the need for this element by 5% and 15%, while in the control sample it is absent.

Preserves with ginger are also rich in ferrum and potassium – 39% and 38%, respectively. Comparing them with other samples, we can conclude that they are most enriched with minerals due to the addition of ginger.

Determination of the content of toxic elements in the composition of preserves is one of the essential characteristics of their health safety (Table 6).

According to the results of Table 6, it was found that the addition of aromatic root vegetables to the composition of preserves is not accompanied by an increase in the level of toxic elements, which guarantees their health safety and suitability for consumption.

The obtained results for determining the chemical composition of preserves made of carp and aromatic root vegetables (Table 1) speak for the fact that the protein content in test samples of preserves ranges from 11.68% to 11.93 %. The lowest protein content was observed in the control sample.

The fat content in the finished preserves ranged from 9.36% to 11.99%, which has a positive effect on the product's taste properties.

Determination of the moisture content in the finished preserves has shown that there is a certain fluctuation in this indicator in the range from 65.61 (preserves with horseradish) to 70.49 (control sample preserves).

In terms of mineral content, the test samples differ in comparison with the control sample. In our opinion, this is because vegetable supplements contain a wide range of minerals, which in combination with minerals contained in fish raw products enrich ready-made preserves (Lebskaya, Pavluchenko and Moisiienko, 2017; Slobodyanyuk et al., 2019).

The sum of individual groups of carp lipid fatty acids corresponds to or exceeds the recommended amount of daily need (Tsypriian, Manasar, Slobodkin, 2007).

Fatty acids play an essential part in human metabolic processes.

Therefore, the composition of fatty acids in food products is vital for ensuring normal metabolism and its correction in various disorders. Accordingly, the composition of fatty acids of the final form of a food product hinges on the characteristics of the ingredients that are used in its production. Among the results of the fatty acid composition of preserve lipids with the use of sunflower oil, MUFAs dominate (33.14 – 38.17%), with the use of sunflower and linseed oil in combination, PUFAs dominate (12.83 – 67.51%).

Changes in the fatty acid composition of preserves (Tables 2, 3) are mainly associated with an increase in the amount of polyunsaturated fatty acids that were introduced with the addition of linseed oil, which is a positive factor.

Among PUFAs, linolenic acid makes up the largest amount (59.58 – 60.09%). The record shows that this acid is vital for humans, it serves mainly as an energy supplier but plays an essential part in the treatment and prevention of cardiovascular diseases, such as coronary heart disease, hypertension, hyperlipoproteinemia, thanks to its lipidlowering, antiplatelet and hypotensive effects (Loizzo et al., 2016).

The degree of lipid fatty acids absorption hinges on the ratio of individual fatty acids and characterizes their biological effectiveness. It does not diverge from practical data. The ratio of individual classes of lipids does not correspond to the recommendations proposed by nutrition specialists. However, data on the ratio of fatty acids ω₆:ω₃ in all types of preserves speak for their high biological efficiency. The record shows that the recommended ratio of PUFAs of ω₆ family/PUFAs of the ω₃family in the diet of a healthy person is 10:1, and in cases of lipid metabolism pathology, it is 5:1 and even 3:1 (Shulgina, et al., 2017; Zheplinska et al., 2019). However, the greatest deficiency in the diet is noted for fatty acids of the ω₃ family. Therefore, the high content of ω₃ family acids in preserve lipids that we have found speaks for their high biological efficiency.

The mineral composition of preserves is characterized by a fairly high content of potassium (93.89 – 108.87 mg.100g^-1), calcium (21.69 – 28.99 mg.100g^-1), sulfur (20.23 – 26.77 mg.100g^-1) compared to the control sample. Based on the study of the mineral composition of fish raw products, the need to optimize it due to the insignificant amount or absence of some essential elements, in particular potassium, manganese, iodine, bromine, selenium, has been proven.

Conducting corresponding research would be very appropriate, as it would make it possible to enrich the recipes of preserves based on freshwater fish with a wide range of vegetable additives, increasing their nutritional value and allowing to get a product rich in such vital nutrients as carbohydrates, calcium, potassium, phosphorus, sulfur, sodium, magnesium, manganese and iron.

Studies on the chemical composition of preserves gave positive results and proved that the addition of aromatic root vegetables increases the mineral content compared to the control sample.

The biological effectiveness of the fatty acid composition of carp preserves is due to an increase in the amount of polyunsaturated fatty acids, namely linoleic acid ω₆, which was introduced with the addition of linseed oil to fish flesh, and compared with the daily requirement exceeds the recommended content.

In comparison with the control sample, in the preserves under study, the level of all mineral elements is significantly increased, which speaks for the expediency of adding aromatic root vegetables to this product to enrich it with these essential elements to obtain high-value and healthy food product. As for the content of toxic elements, preserves with aromatic root vegetables are good for health.

The chemical composition of the experimental formulations differed from the control sample with a higher protein content: 15% vs. 11%, fat: 10 – 12% vs. 9%, and minerals: 9 – 10% vs. 8%, but the energy value of the experimental preserves was higher 144 – 172 in compared with control: 131.

Studies of changes in the quality and safety of preserves during storage have determined the allowable shelf life of preserves no more than 28 days at temperatures from 0 to +4 °C.