Determination of the quality of composite flour mixtures

. This article presents the results of the analysis of wheat and lentil grains grown in the conditions of Uzbekistan. The chemical composition, protein content and amino acid content of lentils were determined. It is clearly stated how the analysis is carried out, what methods and formulas are used. In this regard, the study of the physicochemical characteristics of local varieties of lentil grain seems to be relevant. In recent years, much attention has been paid in the republic to the expansion of wheat and lentil grain sown areas. Such types of leguminous crops are the main sources of obtaining flour. The composition of fodder meal prepared using local lentil grains was analyzed. At the same time, the influence of the technology for obtaining composite mixtures from wheat and lentil flour on the composition of the product was studied. The quality indicators and physico-chemical characteristics of the composite mixture were established when the output amount of composite flour was introduced and simultaneously with the introduction of new technology. Classification of compound flour prepared on the basis of local varieties of lentils. The chemical composition was studied separately for each variety and the effect of composite flour on quality indicators was analyzed.


Introduction
In Uzbekistan, special attention is paid to the cultivation of lentils. Such types of grain are characterized by high quality indicators and physicochemical characteristics [1][2][3].
The indicators of local varieties of lentil grain depend on the agrotechnological measures of their cultivation and the use of various types of mineral fertilizers [4][5][6]. In this regard, the study of the physicochemical characteristics of local varieties of lentil grain seems to be relevant. In recent years, much attention has been paid in the republic to the expansion of sown areas. Such types of leguminous crops are the main sources of obtaining flour. Compilation of composite mixtures of flour from these types of raw materials seems to be topical issues. Composites are characterized by high biological value. One of the ways to create products that provide a healthy diet is to enrich them with vitamins, minerals, protein and dietary fiber [7,8].
The most important role among nutrients belongs to proteins, the main function of which is to supply the human body with amino acids necessary for the synthesis of the body's own proteins [9]. Proteins are a plastic material [10]. Leguminous crops are characterized by a high content of protein substances in their composition [1][2][3]. Some of them are used for the production of flour [4,5].
Local varieties of lentil grain are raw materials for the production of high quality flour. In this regard, research aimed at the production of flour from lentil grains seems relevant. In addition to proteins, dietary fiber is also important. Vegetable dietary fibers are a complex of biopolymers, including cellulose, hemicellulose, pectin substances, lignin [11]. The role of dietary fiber in nutrition is diverse.
Given the above, the main direction of research was aimed at the development of composite flour mixtures based on wheat baking flour, enriched with complete protein, dietary fiber and minerals from lentil seeds. The purpose of the work is aimed at obtaining composite flour mixtures from wheat and lentil grains.

Materials and methods
The objects of the study were lentil seeds of the Sarbon variety, ground to a powder state with a particle size of 400-500 μm, baking wheat flour of the highest, first, second, wallpaper varieties and composite flour mixtures based on them.
In the study of the chemical composition of crushed lentil seeds, the following indicators were determined: mass fraction of water -according to GOST R 54951; proteinby the Kjeldahl method; fat -by extraction method with preliminary hydrolysis of a sample according to GOST 13496.15; dietary fiber -according to GOST 13496.4; ash -according to GOST 27494; minerals: calcium according to GOST 26570; magnesium according to GOST 30502; tryptophan content -according to GOST 13496.21. The coefficient of rationality of the amino acid composition of proteins was calculated using the Lipatov method [12,13].

Results and discussion
The choice of lentils was due to the fact that it has a high nutritional and biological value. Lentil seeds are distinguished by a high protein content (21.3-36.0%), balanced in amino acid composition. In seed proteins, the main fractions are globulins (85.9%), and the proteins are complete in nature. Lentils are rich in minerals, including potassium, calcium, magnesium, zinc, iron, copper, and selenium. In addition, lentil seeds are characterized by a high content of vitamins: β-carotene, PP, B1, B2, B6. Lentil seeds are used both in the daily diet and in medical, children's and vegetarian food [12]. Wheat baking flour of various grades was chosen as the most demanded raw material in the production of many food products. When assessing the biological value of the protein, the following indicators were used.
Utility coefficient of the j-th essential amino acid α j The coefficient of rationality of the amino acid composition R c , which numerically characterizes the balance of essential amino acids in relation to the physiologically necessary norm (standard). In the case when С min ≤ 1, the coefficient of rationality of the amino acid composition can be calculated using the following formula: The indicator of "comparable redundancy" of the content of essential amino acids (σ), which characterizes the total mass of essential amino acids that are not used for anabolic needs in such an amount of the protein of the evaluated product, which is equivalent in terms of their potentially utilizable content to 100 g of the reference protein: In the above formulae, the following designations are accepted: C j -fast j-th essential amino acid of the evaluated protein in relation to the physiological norm (standard); C minthe minimum score of essential amino acids of the evaluated protein in relation to the physiological norm (standard); A j -the mass fraction of the j-th essential amino acid in raw materials, g/100 g of protein; and, A ej -the mass fraction of the j-th essential amino acid corresponding to the physiologically necessary norm (standard), g/100 g of protein.
At the first stage of the study, the chemical composition of crushed lentil seeds was determined and a comparative analysis was carried out with wheat baking flour. The chemical composition of the components of composite flour mixtures is presented in Table  1. As can be seen from the data given in Table 1, in wheat flour, regardless of its variety, as well as in crushed lentil seeds, carbohydrates and proteins predominate. At the same time, the content of proteins in crushed lentil seeds is 24.7%, which is 2.4-2.1 times higher than the content in wheat flour (10.3-11.5%). In addition, crushed lentil seeds are superior to wheat flour in the content of dietary fiber, minerals, including calcium and magnesium. Table 2 shows the amino acid composition of the components of the composite flour mixture. From the data in Table 2 it follows that the proteins of wheat baking flour are not complete. The coefficient of rationality of the amino acid composition (R c ), which numerically characterizes the balance of essential amino acids in flour proteins, is significantly lower (0.47; 0.45; 0.53; 0.58) in relation to the physiologically necessary norm (1.0) and in comparison with proteins of crushed red lentil seeds (0.79). In addition, wheat flour proteins differ in the values of the "comparable redundancy" index of the content of essential amino acids (σ) (40.3; 43.6; 32.5; 26.0), which significantly exceed the standard (0). When developing composite flour mixtures, we were guided by the basic principle of the process of creating a new product with an increased biological value of the protein. Analysis of the data presented in Table 2 shows that the addition of crushed lentil seeds to wheat flour makes it possible to create a product with a high content of protein (18.9-17.0%), dietary fiber (11.32-8.6%) and minerals (2.21-1.9%), including calcium and magnesium. At the same time, compared with wheat varietal flour (Table 2), the Ca:Mg:P ratio in composite flour mixtures is closer to the optimal one. The developed composite flour mixtures differed in organoleptic characteristics from baking wheat flour in smell and color. Composite flour mixtures had the following color characteristics: based on wheat baking flour of the highest and first grades -creamy with the inclusion of small red particles; wheat baking flour of the second grade -creamy with a grayish tinge with the inclusion of small gray particles; Whole wheat baking flour -creamy with a grayish tint with noticeable particles of grain shells and with the inclusion of small particles of yellow color.

Conclusions
Thus, a comparative analysis of the chemical and amino acid compositions of baking wheat flour and crushed lentil seeds showed a significant superiority of the latter in terms of protein content and its biological value, dietary fiber and minerals, including calcium and magnesium. These facts served to select lentil seeds, ground to a powder state with a particle size of 400-500 microns, as a component in the development of composite flour mixtures based on wheat baking flour with high nutritional and biological value.