DESIGN OF TECHNOLOGY FOR THE RYE-WHEAT BREAD "KHARKIVSKI RODNICHOK" WITH THE ADDITION OF POLYFUNCTIONAL FOOD ADDITIVE "MAGNETOFООD"

Bread is a staple food that is consumed on a daily basis [1], so its quality must meet all the medical and biological requirements [2]. These indicators depend on a number of factors, the main of which is the quality of basic and additional raw materials used in the production of bread [3]. The industry processes up to 50 % of the total volume of flour with decreased properties [4], large bread-making factories employ continuous technologies that have a number of shortcomings, including those affecting the quality of bread [5]. There is still a not sufficiently satisfied need of the population in products with medical-dietary and prophylactic effect, especially in the environmentally-stressed areas, as well as the need in in bread with long shelf life [6]. One of the directions for improving existing, as well as designing new, technologies of food products is the development of methods for obtaining and use of food additives – enrichment agents and improvers. This will ensure: – improvement in the quality and nutritional value of products; – increase in the output of finished products; – in some cases, improvement of functional-technological indicators and longer storing of food products. In recent years, in order to create required functional-technological properties of bread, new technologies have been developed, which involve flour improvers, food additives, enrichment agents with a different principle of action, with various technological techniques applied. These innovations are necessitated, first, by the proliferation of DESIGN OF TECHNOLOGY FOR THE RYE-WHEAT BREAD "KHARKIVSKI RODNICHOK" WITH THE ADDITION OF POLYFUNCTIONAL FOOD ADDITIVE "MAGNETOFООD"


Introduction
Bread is a staple food that is consumed on a daily basis [1], so its quality must meet all the medical and biological requirements [2]. These indicators depend on a number of factors, the main of which is the quality of basic and additional raw materials used in the production of bread [3]. The industry processes up to 50 % of the total volume of flour with decreased properties [4], large bread-making factories employ continuous technologies that have a number of shortcomings, including those affecting the quality of bread [5]. There is still a not sufficiently satisfied need of the population in products with medical-dietary and prophylactic effect, especially in the environmentally-stressed areas, as well as the need in in bread with long shelf life [6].
One of the directions for improving existing, as well as designing new, technologies of food products is the development of methods for obtaining and use of food additives -enrichment agents and improvers. This will ensure: -improvement in the quality and nutritional value of products; -increase in the output of finished products; -in some cases, improvement of functional-technological indicators and longer storing of food products.
In recent years, in order to create required functional-technological properties of bread, new technologies have been developed, which involve flour improvers, food additives, enrichment agents with a different principle of action, with various technological techniques applied. These innovations are necessitated, first, by the proliferation of single-phase accelerated techniques for dough preparation; second, by the unstable quality of flour and raw materials, specifically, of those with prophylactic effect; third, by the extension of product range; fourth, by improvement in the quality of finished products, by increasing nutritional value and better resistance against microbial spoilage; fifth, by longer shelf life of bread and bakery products [6].
Improvers are the natural or synthetic substances that make it possible to adjust functional properties of food products; to intensify technological process of bread production. They also regulate the rheological properties of dough, alter organoleptic and functional-technological indicators. Specifically, they enhance the color and flavor of products, improve their shape and volume, improve the structure and properties of crumb, increase the degree of freshness of bread, etc.
It is necessary to purposefully use the improvers in order to improve the basic and additional raw materials.
At present, an important task in the production of bread and bakery products is the search for alternative raw materials. Such raw materials should alter technological properties, have rich chemical composition and various structural components. They would not only activate biotechnological processes in the production of bread but also save raw materials used in bread making. Most importantly, they would improve chemical composition and quality of the finished product.
The intensity of the course of biotechnological processes during bread production depends on the quality of rye and wheat flour, rye sourdough and the yeast used. Quality of rye sourdough depends on many factors, but to a greater extent on the composition of nutrient medium in which the cultivation of a given semi-finished product takes place. One of the techniques to improve composition of the nutrient medium for the cultivation of rye sourdough is the introduction of supplements-improvers into composition [2,3,5].
Therefore, in order to improve bread baking technologies, it is of practical interest to apply various additives. Food additives would enable enrichment of nutrient mixtures in order to cultivate rye sourdough with necessary substances. It contributes to the improvement of biotechnological quality indicators of rye sourdough, as well as ryewheat dough. In addition, the use of additives and improvers in bread-making technology makes it possible to intensify technological process of production and improve quality of the finished product.
Given this, it is a relevant task to introduce the polyfunctional food supplement "Magnetofооd" into a formulation composition in order to create new functional-technological properties of rye-wheat bread. "Magnetofооd" is an ultra-thin powder with a particle size of 30−60 nm and with a large specific surface, high activity and specific properties: restoring, antioxidant, bacteriostatic, sorption, complexing, emulsifying, moisture-retaining, fat-retaining, moisture-binding. It is an additional source of easily digestible iron (II) [7][8][9].

Literature review and problem statement
An analysis of the scientific literature shows that nutritional supplements are used in the practice of bread making in order to extend product range and improve quality of bread and bakery products, to regulate parameters of technological processes. They can be divided into several groups: -derived from plant and animal raw materials (products from seeds of legumes, fruit powders, dairy products, etc.); -obtained chemically (antioxidants, synthetic vitamins, etc.); -obtained using microbiological synthesis (enzyme preparations); -resulting from processing natural materials (modified starch).
We shall consider these groups separately and in more detail.
Each group has certain advantages and disadvantages. The advantages of the first group, in whose composition plant supplements are most widely used, are a complex composition, balanced constituents of individual components, as well as the presence of compounds in the most physiologically digestible form. Enrichment of vegetable, fruit and herbal additives with biologically active substances promotes the increase of viscosity of dough, reduction of its adhesion, improvement of the pliability of dough to mechanical treatment; improvement in specific volume, porosity and shape stability of bread [10][11][12][13][14][15]. Disadvantages include narrow orientation and the absence of comprehensive effect.
With the aim of enriching bread with food fibers, specialists employ technologies of bread with added hardly-digestible polysaccharides (bran cereals, peas, sunflower seeds, wheat germs, oatmeal, banana and apple powders, buckthorn shroud) as well as the ethers of cellulose [12][13][14][15].
However, their effect on technological indicators of dough semi-finished products and finished products is insignificant.
Thus, in order to enrich bakery products with plant protein, specialists use soybeans and products of processing [16,17]. Technologies of dietary products in bread and bakery industry widely utilize residual products of beer brewing: salt-laden barley grain, beer pebble and remaining beer yeast [2,6]. The disadvantages of using such additives include low threshold of antioxidant and antimicrobial effect.
There are known bread technologies with the additives of animal origin based on milk and certain products of its processing, which positively affect the properties of dough and the quality of bread [10,[18][19][20][21]. Disadvantages include substantial friability and insufficient elasticity of crumb.
Bread baking industries apply supplements-improvers for the regulation of technological properties of dough. They are divided into several groups [22]: -improvers with oxidative effect; -improvers based on modified starches; -improvers with surface-active properties; -improvers of fermentative nature; -mineral improvers.
The following improvers with oxidative effect have gained the most practical application in the technology of bread preparation: potassium bromate, ascorbic acid, azodicarbonamide, calcium and benzoyl peroxides [22]. The disadvantages of these additives are a low functionality in terms of texture and physical-chemical properties of baked goods.
Some technologies involve modified starches (extrusion, oxidized, swelling, phosphate, esterified), which makes it possible to improve specific volume and looseness of bread crumb. The elasticity of crumb and the color of bread are also improved. Shelf-life of finished products is prolonged [22]. These improvers, however, do not possess antioxidant properties.
Enzyme supplements (amylolytic, proteolytic, cellulolytic, pentosanes, β-galactosidase, lipoxygenase) are most efficiently applied in the technologies for processing dough with reduced fermentative activity [23]. The shortcoming of using such additives is the fact that they do not ensure sufficient output of finished products.
Mineral supplements-improvers (ammonium salts of orthophosphoric acid, sodium and potassium orthophosphates) are employed in bread making mainly to improve the activity of yeast. Their use stabilizes the rheological properties of dough, increases the volume of bread, improves porosity of crumb and eliminates its stickiness [24]. The disadvantage of these additives is the insufficient functionality in terms of specific volume, porosity and shape stability of bread.
There is known positive effect of calcium salts on the activation of flour amylases and other enzyme preparations, as well as the additives of calcium acetates and propionates to prevent molding and potato disease of bread [25]. These improvers, however, do not provide sufficient structural-mechanical and physical-chemical indicators.
In recent years, the process of bread production has commonly involved complex improvers that contain several components with different functional properties. The composition consists of enzyme preparations, antioxidants, surface-active substances, mineral salts, supplements with dietary and preventive effect. These supplements positively affect carbohydrate and protein complex of flour; the vital activity of yeast; the process of gas formation during dough fermentation, and the rheological properties of dough semi-finished products. The result is the improvement in quality indicators of bread and bakery products: an increase in the specific volume of bread, in porosity and structural-mechanical properties of crumb, shape stability of bread, and inhibition of the staling of finished products at storing [24][25][26]. The shortcomings include a low threshold of antioxidant and antimicrobial effects.
Modern food technologies widely employ functional ingredients obtained from industrial by-products (skin, hoof, feathers, offal, seeds, bran, whey, etc.). These supplements, however, are characterized by narrow orientation and do not demonstrate comprehensive effect [27,28].
Bread containing wheat flour is a food with low antioxidant capacity. In recent years, bread making technologies have followed a global trend to enrich bread with phenolic antioxidants of plant origin [29,30]. The disadvantages of these additives are a low functionality in terms of texture and physical-chemical properties of baked goods.
Bread technologies use additives based on wheat with a low content of glycemic index (GI) in order to improve health of consumers [31]. The yield and structural-mechanical indicators of finished products, however, do not improve.
The use of essential oils as natural antimicrobial agents for bakery products was reported [32]. In this case, the elasticity and porosity of crumb do not improve.
Various supplements are proposed for use in baking technologies in order to improve quality indicators of bread (especially gluten-free): soy, chickpeas, eggs, enzymes, hydrocolloids, microalgae, etc. [33][34][35][36]. These supplements have a number of disadvantages: -chickpeas exert a negative effect on bread quality due to the loss of solubility at baking; -adding microalgae does not significantly affect hardness and elasticity of dough semi-finished products; -some do not improve shape stability, yield, acidity and moisture-content of crumb.
The dietary supplement "Gemovital" is used in the technology of rye-wheat bread, rye-wheat crackers and gingerbread for enriching them with valuable protein and iron in the form easily digestible for the human organism. The main task of "Gemovital" is physiological effect on the organism. The functional-technological properties of dough and finished products are not much affected by "Gemovital" [37][38][39].
An analysis of recent studies and publications [27][28][29][30][31][32][33][34][35][36] on the development of new advanced technologies for bread and bakery products production reveals profound changes in traditional technologies of bakery products. In recent years, technologists have increasingly paid attention to innovations in the direction of improving biological value; functional-technological, physical-chemical and organoleptic indicators; creating bread and bakery products with dietary and medicinal-preventive properties.
Leading direction in the technology of bakery products is the inclusion of compounds of varying nature to formulations that are related to food additives and improving additives. This opens up almost unlimited possibilities for the use of food additives in the production of functional food products.
In order to create new functional-technological properties in the technologies of bread and bakery products, it is possible to suggest using the polyfunctional food supplement "Magnetofооd" -a nanopowder with large specific surface and high activity. The composition of this supplement includes oxides of two-and three-valent ferrum. This food additive possesses a number of properties: biological compatibility with living organisms, affinity to the protein, bacteriostatic action, high thermal stability. In food systems, "Magnetofооd" exhibits regenerative, antioxidant, sorption, complexing, emulsifying, moisture-retaining, fat-retaining, moisture-binding properties, and can also act as an additional source of easily-digestible iron [7][8][9]].
An analysis of information sources [2, 3, 5, 6, 10-15, 17-26, 29-36] reveals the lack of data on the technology of bread making using polyfunctional food additives, specifically of the nanopowder type, which improve technological parameters of semi-finished products and quality of bread. The discovered properties of the additive "Magnetofооd" allow us to recommend it for improving functional-technological indicators of rye-wheat bread.

The aim and objectives of the study
The aim of present work is to design the technology of rye-wheat bread with the addition of polyfunctional food supplement "Magnetofооd".
To achieve the aim, the following tasks have been set: -to investigate the effect of the food additive "Magnetofооd" on physical-chemical parameters of the experimental samples of rye-wheat dough; -to investigate the effect of the food additive "Magnetofооd" on technological indicators of the experimental samples of rye-wheat dough; -to investigate the effect of the food additive "Magnetofооd" on physical-chemical and technological indicators of the experimental samples of the bread "Kharkivski rodnichok"; -to investigate the effect of the food additive "Magnetofооd" on organoleptic indicators of the experimental samples of the rye-wheat bread "Kharkivski rodnichok".

1. Examined materials and equipment used in the experiment
We investigated in the present study the effect of the polyfunctional food supplement "Magnetofооd" on physical-chemical, technological and organoleptic indicators of rye-wheat dough and the finished product.
The examined materials and equipment used in the experiment, as well as techniques for determining organoleptic, physical-chemical and technological indicators, are described in detail in paper [40].

Results of study of the effect of the food additive "Magnetofооd" on quality indicators of the experimental samples of wheat-rye bread
We studied effect of the polyfunctional food supplement "Magnetofооd" on rye-wheat bread on model systems. The base formulation that we chose to examine is the rye-wheat dough formulation, which is used for making the bread "Darnytski" (Table 1) [41].
Two techniques were applied to introduce the polyfunctional food supplement "Magnetofооd": 1) the food additive "Magnetofооd" was introduced in a dry form when kneading the dough in the amount of 150 g per 100 kg of flour; 2) the food additive "Magnetofооd" was introduced in the form of OMS (oil-magnetofооd suspension) in the amount of 350 grams per 100 kg of flour when kneading the dough. The optimal quantity of the food additive "Magnetofооd" and OMS was chosen experimentally.
OMS was used for better distribution of the polyfunctional food supplement "Magnetofооd" and for obtaining a homogeneous structure of dough and bread.  Fig. 1 shows duration of the fermentation of rye-wheat dough in the experimental samples whose formulation is given in detail in Table 1. Table 1 Formulation of experimental samples of the rye-wheat bread "Darnytski" and "Kharkivski rodnichok" with the food additive "Magnetofооd"  Results of research into physical-chemical indicators of the experimental samples of rye-wheat dough are given in Table 2. Data from Table 2 show that moisture content and acidity of the dough were different in experimental samples. Moreover, introduction of the food supplement "Magnetofооd" to rye-wheat dough helps to reduce moisture content and acidity of the dough: -by 1.0 % and 2.7-4.0 %, respectively (for the dough prepared using wheat flour of grade 1 and pressed yeast); -by 5.8 % and 7.1-8.2 %, respectively (for the dough prepared using wheat flour of grade 2 and pressed yeast with low amylolytic activity).
The introduction of the food additive "Magnetofооd" also affects the yield of the dough. Indicators of the yield for the experimental samples of rye-wheat dough are shown in Fig. 2.
By analyzing experimental data in Fig. 2 we can conclude that the use of the food additive "Magnetofооd" leads to an increase in the yield of dough.
Organoleptic indicators of bread quality significantly affect consumer demand. Table 3 and Fig. 3-6 show the esti-mate of organoleptic indicators of the experimental samples of rye-wheat bread "Kharkivski rodnichok" compared with control samples (by a five-point scale).   Fig. 3. Effect of the food additive "Magnetofооd" on organoleptic indicators of experimental sample 2 of the rye-wheat bread "Kharkivski rodnichok" compared with control (bread "Darnytski", prepared using wheat flour of grade 1 and pressed yeast) Experimental data in Table 3 and Fig. 3-6 show that applying the polyfunctional food supplement "Magnetofооd" in the production of rye-wheat bread "Kharkivski rodnichok" improves its organoleptic properties: taste, color, porosity and crumb state. Table 4 gives physical-chemical indicators of the experimental samples of rye-wheat bread "Kharkivski rodnichok" compared with control samples.  Table 4 show that physical-chemical indicators for the experimental samples of rye-wheat bread "Kharkivski rodnichok" with the addition of food additive "Magnetofооd" are better than for control samples without food additive "Magnetofооd".
The influence of the polyfunctional food supplement "Magnetofооd" on the yield for the experimental samples of rye-wheat bread "Kharkivski rodnichok" compared with control samples is shown in Fig. 7 Table 4 Results of research into physical-chemical indicators of the experimental samples of bread "Kharkivski rodnichok" compared with control samples Data in Fig. 7 show that the yield of bread in the experimental samples of rye-wheat bread "Kharkivski rodnichok" with the addition of food additive "Magnetofооd" is higher than that in the control samples without food additive "Magnetofооd".
Based on results of the study, we propose a technological scheme for the production of rye-wheat bread "Kharkivski rodnichok" with the addition of the polyfunctional food supplement "Magnetofооd" (Fig. 8) [34][35][36].
A distinctive feature of the new technology is the preliminary mixing of the food additive "Magnetofооd" with the wheat flour, which is used when kneading the dough [41].
The dough for preparing the rye-wheat bread "Kharkivski rodnichok" is prepared using thick leaven with moisture content 48-50 %. Table 5 gives the formulation and basic parameters for preparing dough using thick leaven [41].
When kneading the dough, a portion of leaven is mixed with a yeast suspension, a sugar-saline solution, a concentrate of leavened wort and water. Then wheat flour is introduced, preliminary mixed with the food additive "Magnetofооd". Kneading lasts for (12-15)×60 s. Dough matures for (50−60)×60 s at a temperature of 25−28 °C. Acidity of the matured dough is not less than 10−12 degrees by Neumann. At the next stage, dough is divided into pieces with a certain weight, make them round-shaped, put into molds, greased with oil, and taken to the chamber for aging over 60×60 s at a temperature of 30−32 °С and relative air humidity 75−80 %.
Cooling and storing bread after baking is carried out under conditions of a bread storing facility at relative air humidity 70−75 % [35,36,41].
In order to implement a technological process of the production of rye-wheat bread "Kharkivski rodnichok" using the food additive "Magnetofооd", it is proposed to apply the equipment, shown in Fig. 9, at the stage of dosing raw materials and mixing the additive with wheat flour. \\\\ Fig. 9. Unit for the fortification of flour with magnetofооd: 1 -storage of flour in containers; 2 -vibratory sifter unloader; 3 -device for the transportation of ingredients; 4 -bunker for supplying the flour; 5 -bunker for supplying the polyfunctional food supplement "Magnetofооd"; 6 -screw micro dozer; 7 -screw conveyor-agitator: I -flour, II -magnetofооd, III -fortified flour for kneading Technological scheme of the bread "Kharkivski rodnichok" easily fits the work of enterprises in the baking industry and can be implemented without significant changes in the organization of their work.

Discussion of results of the study of properties of the additive "Magnetofооd" in the technology of rye-wheat bread
One of the basic stages in bread production is the kneading of dough. The kneading of dough is performed in dough-mixing machines with the purpose of obtaining from the components of a formulation the dough uniform in its mass and structure. After the kneading dough undergoes fermentation. Fermentation is carried out in order to obtain dough with optimal organoleptic and rheological properties. These properties are acquired by dough as a result of alcohol and lactic acid fermentation caused by yeast cells and lactic acid bacteria. Control over dough kneading is performed based on organoleptic indicators (flavor, structure, an increase in volume, taste), moisture content and acidity. The quality of dough affects quality of bread [3,5].
The quality of raw materials significantly affects the duration and temperature of dough fermentation, as well as the technology of its preparation. Dough fermentation time is determined by the resulting temperature and acidity. Initial temperature of dough for the production of rye-wheat bread "Darnytski" according to production regulations should be 27 °C, dough fermentation finishes at a temperature of 30 °C. Moisture content of the dough should be 48.5 %, acidity 7-8°. Optimum dough fermentation time for the bread "Darnytski" at good starting raw material is 60 minutes, the yield of dough in this case will reach 164 % [3,5].    1 shows that we observe minimum dough fermentation time in samples 2, 3 (in this case, when the food additive "Magnetofооd" was introduced in the form of OMS, sample 3, the effect is 11 % better in comparison with the technique for introducing it in the dry form − sample 2). In control sample 4 (for dough prepared using wheat flour of grade 2 and pressed yeast with low amylolytic activity), dough fermentation time was maximum − 70 min. It was 10 minutes longer in comparison with control sample 1 (for dough prepared using wheat flour of grade 1 and pressed yeast). This time difference is associated with the use of low quality wheat flour and pressed yeast with reduced amylolytic activity. Consequently, the dough was poorly kneaded and did not reach the required temperature. In samples 5, 6 (the introduction of food additive "Magnetofооd" to which was carried out in the form of OMS, sample 5, and in a dry form, sample 6), dough fermentation time, compared with control sample 4, was 5 and 10 min. less, respectively. However, dough fermentation time for these experimental samples 5, 6 also exceeded that of control sample 1 by 5-10 min., respectively. Here, compared with experimental sample 4, we observed reduced time of fermentation, which is probably due to the activating properties of Fe 3 O 4 , which is the basic component of food additive "Magnetofооd".
Nanoparticles of the food additive "Magnetofооd" have a biological compatibility with protein components of enzymes and the capability to interact with them through activation, with improves the quality of dough via influence on ß-amylase.
When analyzing Fig. 1, it can be assumed that the use of the polyfunctional food supplement "Magnetofооd" in the production of rye-wheat bread "Kharkivski rodnichok" leads to a reduction in the time of fermentation of dough. It also makes it possible to bring the time of fermentation of dough prepared with wheat flour of grade 2 and pressed yeast with low amylolytic activity closer to control sample 1 (dough prepared using wheat flour of grade 1 and pressed yeast).
Data in Table 2 show that the introduction of food additive "Magnetofооd" significantly affect physical-chemical indicators of dough. In samples 1, 6, we obtain dough whose moisture content and acidity met the standard requirements [GOST 26983-2015]. In samples 2, 3 (the food additive "Magnetofооd" to which was introduced in the form of OMS, sample 3, and in a dry form, sample 2), moisture content and acidity of the dough were about 1.0 % and 2.7-4.0 % lower, respectively. In experimental sample 4 (the dough was prepared using wheat flour of grade 2 and pressed yeast with low amylolytic activity), we observe increasing moisture content and acidity of the dough: 6.0 % and 1.0° higher, respectively, than that in control sample 1. This may be due to the use of low-quality flour, as a result of which dough accumulates large amounts of water-soluble substances. Increasing acidity is due to the fact that in the course of their life activities acid-forming bacteria decompose glucose with the formation of lactic acid. At the same time, dough accumulates as by-products a certain amount of other organic acids: acetic, succinic, malic, citric, wine, formic [3,5]. And since the time of fermentation in this sample was longer, the content of the above acids was greater. In samples 5, 6, we used wheat flour of grade 2, pressed yeast with low amylolytic activity and the food additive "Magnetofооd". In sample 5, "Magnetofооd" was introduced in a dry form; in sample 6 -in the form of OMS. We can observe in these samples improvement of the physical-chemical properties of dough and that these indicators approach the standard requirements -control sample 1 [GOST 26983-2015]. This is probably due to the use of the polyfunctional food supplement "Magnetofооd", which reduced the time of fermentation of dough and improved its indicators. In addition, the introduction of food additive "Magnetofооd" not only slows down the processes of hydrolysis of carbohydrate and protein components of dough (the accumulation of free organic acids) but also sorbs some amount of organic acids on Fe 3 О 4 . This indicates that "Magnetofооd" improves the quality of dough.
The maximum yield of dough was obtained in experimental samples 2, 3 (Fig. 2). They were introduced with the polyfunctional food additive "Magnetofооd" in a dry form, sample 2, and in the form of OMS, sample 3. In samples 2, 3, the yield of dough exceeded that of control sample 1 by 2.1 % and 3.7 %, respectively. In control sample 4, we used wheat flour of grade 2 and pressed yeast with low amylolytic activity. In this sample, the yield of dough was minimal, 2.1 % less than that of control sample 1. In experimental samples 5, 6 (prepared using wheat flour of grade 2 and pressed yeast with low amylolytic activity), the yield of dough compared with that of control sample 4 was higher by 3.8 % and 1.2 %, respectively. In experimental samples 5, 6, the yield of dough also met the standard requirements -control sample 1 [GOST 26983-2015]. Analyzing the experimental data, we can conclude that the use of food additive "Magnetofооd" in the production of rye-wheat bread "Kharkivski rodnichok" leads to an increase in the yield of dough. After all, in experimental sample 5 (the dough prepared using wheat flour of grade 2 and pressed yeast with low amylolytic activity), it is the application of the food additive "Magnetofооd" that made it possible to obtain the yield of dough close to that in control sample 1, while experimental samples 2, 3, 6 had a larger yield.
Physical-chemical and technological indicators of bread quality characterize strict adherence to the formulation and the procedure of technological process at a bread baking enterprise. This group includes moisture content, acidity, and porosity.
In experimental samples 2, 3, 5, 6 with the food additive "Magnetofооd", the rye-wheat bread "Kharkivski rodnichok" exhibited better physical-chemical and technological indicators compared with control samples 1 and 4. First, the moisture content and acidity of bread decreased: -by 1.0 % and by 7.1−10.7 %, respectively (for the dough prepared using wheat flour of grade 1 and pressed yeast); -by 5.9 % and by 10.0−12.5 %, respectively (for the dough prepared using flour of grade 2 level and pressed yeast with low amylolytic activity).
Second, the porosity of crumb bread grew: -by 3.4−5.1 % (for the dough prepared using wheat flour of grade 1 and pressed yeast); -by 3.6−5.4 % (for the dough prepared using flour of grade 2 level and pressed yeast with low amylolytic activity).
An increase in the porosity occurred, probably, due to the biochemical processes. The action of nanoparticles in the food additive "Magnetofооd" activates vital activity of microflora in dough semi-finished products. The result is the enhanced release of CO 2 ; thermal expansion of air bubbles and CO 2 ; the increase in the migration of ethanol that is produced as a result of the process of alcohol fermentation to the gaseous state, with further thermal expansion of its vapor [3,5]. In control sample 4 (prepared using wheat flour of grade 2 and pressed yeast with low amylolytic activity), the rye-wheat bread was inferior in terms of moisture content and porosity to all experimental samples of the bread "Kharkivski rodnichok", the acidity was maximal and corresponded to the upper limit in GOST. In samples 5, 6 (where we used wheat flour of grade 2, pressed yeast with low amylolytic activity, and the food additive "Magnetofооd"), the rye-wheat bread "Kharkivski rodnichok" met requirements of the standard. By analyzing data in Table 4 we can conclude that it was the action of the food additive "Magnetofооd" that made it possible for experimental samples 5, 6 to meet the requirements of GOST 26983-2015 for physical-chemical and technological indicators of bread quality, and for samples 2, 3 to show the best results.
The yield of bread is one of the main technical-economic indicators of performance of a bakery enterprise. The yield of bread is understood as the weight of finished products, expressed as a percentage to the weight of the utilized flour (typically per 100 kg of flour) [3,5]. Fig. 7 shows that the maximum yield of the rye-wheat bread "Kharkivski rodnichok" was obtained in experimental samples 2, 3 (with the food additive "Magnetofооd"), which was 3.3-3.6 % higher than that in GOST. Experimental samples 5, 6 (with the food additive "Magnetofооd") enable the yield of bread larger than that of control sample 4, by 4.0-4.5 %, and their yield is only 0.7-1.0 % lower than that of control sample 1. It should be noted that all experimental samples of the bread "Kharkivski rodnichok" with the addition of food additive "Magnetofооd" demonstrated the larger yield of bread than that in experimental samples of the bread "Darnytski" without added "Magnetofооd".
By analyzing obtained experimental data, we can conclude that the use of food additive "Magnetofооd" in the production of rye-wheat bread "Kharkivski rodnichok" leads to an increase in its yield. First, due to the moisture-retaining capacity of the primary component of "Magnetofооd" -Fe 3 О 4 . It helps maintain dough moisture content at the boundary level and ensures standard moisture content in bread. Second, nanoparticles of "Magnetofооd" are capable of activating the action of enzymes. This contributes to lowering the temperature and reducing the time of dough fermentation.
Thus, using the polyfunctional food supplement "Magnetofооd" leads to a significant improvement in the quality indicators of rye-wheat bread. It could be applied when using raw materials of low quality, which was implemented in the design of technology for the rye-wheat bread "Kharkivski rodnichok". Given this perspective, the research results are of interest not only for Ukraine but for the entire scientific world.

Conclusions
1. It was established that the introduction to wheat flour of the polyfunctional food supplement "Magnetofооd" helps to reduce the moisture content and acidity of dough: -by 1.0 % and by 2.7-4.0 %, respectively (for the dough prepared using wheat flour of grade 1 and pressed yeast); -by 5.8 % and by 7.1−8.2 %, respectively (for the dough prepared using flour of grade 2 and pressed yeast with low amylolytic activity).
2. It was proven that adding the food additive "Magnetofооd" helps to reduce the time of dough fermentation: -by 10.0−16.7 % (for the dough prepared using wheat flour of grade 1 and pressed yeast); -by 7.1-14.3 % (for the dough prepared using flour of grade 2 and pressed yeast with low amylolytic activity); -increases dough yield by 2.1-3.7 %. 3. It was established that the introduction of food additive "Magnetofооd" to flour: 1) helps to reduce the moisture content and acidity of bread: -by 1.0 % and by 7.1−10.7 %, respectively (for the dough prepared using wheat flour of grade 1 and pressed yeast); -by 5.9 % and by 10.0−12.5 %, respectively (for the dough prepared using wheat flour of grade 2 and pressed yeast with low amylolytic activity); 2) helps increase porosity of the bread crumb: -by 3.4−5.1 % (for the dough prepared using wheat flour of grade 1 and pressed yeast); -by 3.6−5.4 % (for the dough prepared using wheat flour of grade 2 and pressed yeast with low amylolytic activity).
It was proven that experimental samples of the rye-wheat bread "Kharkivski rodnichok" with the addition of food additive "Magnetofооd" demonstrated the yield of bread that is larger than that in control samples without added "Magnetofооd" by 3.3−3.6 %.
4. It was established that using the polyfunctional food additive "Magnetofооd" in the production of rye-wheat bread "Kharkivski rodnichok" improves its organoleptic properties: taste, color, porosity and condition of crumb, by 1-2 points on average, compared with control samples.
Based on the research results, we proposed functional scheme for a technological process of the rye-wheat bread "Kharkivski rodnichok" with the addition of polyfunctional food additive "Magnetofооd".