DETERMINATION OF PROTEIN CONTENT IN DIFFERENT BRYNZA SAMPLES

АННОТАЦИЯ

In this article, we will discuss the protein content of 4 different brynza products. The determination using the Keldal and Dumass methods was compared, and the Keldal method was chosen as the most optimal option, and the protein content in the brynza product was determined using this method.

Determining the protein content in cheese products is one of the most important metrological factors in the food industry. Through this laboratory study, the protein content in the brynza product was studied, and in what cases the protein content in the product was higher was investigated.

ABSTRACT

В статье обсуждается содержание белка в 4 различных продуктах брынзы. Сравновалось определение методом Келдаля и Дюмаса, метод Келдаля был выбран как наиболее оптимальный вариант, а содержание белка в брынзовом продукте определялось с использованием данного метода.

Определение содержания белка в сырных продуктах является одним из важнейших метрологических факторов в пищевой промышленности. Посредством данного лабораторного исследования было изучено содержание белка в брынзовом продукте и в каких случаях содержание белка в продукте было выше.

Keywords: brynza, Keldal methods, protein, nitrogen, sample.

Ключевые слова: brynza, методы Келдаля, белок, азот, проба.

Introduction. Milk and many products made from it, including various cheeses, are becoming increasingly important in the human diet. They are a very valuable source of high-quality food proteins. The digestibility of these proteins ranges from approximately 95% to 98%.

The amount and type of proteins in brynza can vary significantly depending on the type of milk used and the production process. For example, fresh cheeses, such as ricotta or spread cheese, contain more serum proteins, while mature cheeses, such as Parmigiano Reggiano and Pecorino, are rich in casein. The proteins in brynza are of high quality and contain all the essential amino acids necessary for the human body. Therefore, brynza is considered a complete (complex) protein source and is especially beneficial for those who have chosen a vegetarian diet or have a high protein requirement [1].

Additionally, the proteins in brynza are easily digestible and are an excellent choice for people of all ages, including children and the elderly. The degree of protein digestibility can vary depending on the type of cheese and its maturity. Brinza proteins are mainly divided into two main groups: casein and serum proteins. About 80% of all proteins in milk are casein, and the remaining 20% are whey proteins. Both groups have unique properties that shape the physical and nutritional properties of brynza [2].

Casein is a slowly absorbed protein that provides the body with stable and long-term amino acids. This makes it especially beneficial for maintaining muscle mass and recovery after exercise [2].

Serum protein on the contrary, is rapidly absorbed and is ideal for immediate recovery, especially after exercise. It is rich in branched-chain amino acids (BCAA), which play an important role in the synthesis of muscle proteins. Serum protein is often isolated and used as a biological supplement for athletes and people with an active lifestyle [3].

In addition, some brynzas are additionally heat-treated during the production process - this stage lasts from 45 to 50 minutes and is carried out at a temperature of 55°C. These treatments can lead to changes in the chemical composition of milk components to varying degrees, sometimes profound. Proteins play a key role in the development of human body tissues, their normal functioning, and continuous renewal. Among milk and dairy products, brynza contains more protein, that is, 100 grams of brynza contains 20-30 grams. According to the World Health Organization's nutrition guidelines, 50 grams of brynza meet 25% of the adult's daily protein requirement [5].

Proteins are complex and high-molecular-weight nitrogen compounds. Amino acids are formed on the basis of protein molecules. Proteins in milk and dairy products consist of approximately 20 different amino acids, 9 of which are irreplaceable, meaning the body cannot synthesize them independently and must be consumed with food [4-5].

Proteins in milk and dairy products are variable, and their quantity varies depending on the cow breed, feed type, location, and other factors. In the human body, milk proteins are easily digested, easily broken down, and highly absorbed.

The total protein content in milk products is 3.4%, the main part of which is casein, i.e., 2.8%. The protein content in brynza varies depending on the type, but on average, 100 grams of brynza contains 250-300 kcal, 25% fat, and 15-17% protein. The protein in brynza contains nitrogen-containing compounds and a set of essential and essential amino acids. 95-96% of the protein in brynza is formed by amino acids and 2.5-3.5% by non-protein nitrogenous compounds. 37-43% of the amino acids in brynza protein are irreplaceable, and 55-60% are replaceable [6].

The protein content in brynza products ranges from 24% to 28%. For this type of brynza, the main protein norm is taken as 25%. Determining the protein content in milk and dairy products is one of the most important analyses in food chemistry, as the protein content in the product indicates its quality and the quality of the production process. Brinza There are two widely used methods for determining protein content, which are the Keldal and Dumass methods [5-6].

The Keldal method is considered one of the most widespread classical methods. In this method, the protein content of the product is determined by the total nitrogen content in the product. The essence of the method is that the organic substances in the sample decompose by boiling in concentrated sulfuric acid, forming ammonia salts. The resulting ammonia is evaporated with alkali and sent to an acidic solution. Then the amount of ammonia is determined by the titrometric method, and based on the result, the amount of nitrogen in the analyzed sample is calculated [5-6].

A moderately ground and homogenized sample of the studied sample is taken for analysis and weighed in a test tube with an accurate weight with a maximum error of 0.1%. The sample quantity is completely transferred to the Kjeldal flask. Subsequent experiments are conducted based on methodological instructions [7].

Processing of the results: When determining the mass fraction of nitrogen (X) in the analyzed sample as a percentage by evaporating ammonia into sulfuric acid, it is calculated according to the following formula: (not paraphared)

                                                             (1)

where:

V₀ - volume of 0.1 mol/l sodium hydroxide solution used for the titration of sulfuric acid at a concentration of 0.05 mol/l in the control experiment, ml; V1 - volume of 0.1 mol/l sodium hydroxide solution used for titration of the analyzed solution, ml; K - correction coefficient to the titer of 0.1 mol/l sodium hydroxide solution; 0.0014 - the amount of nitrogen equivalent to 1 ml of a 0.05 mol/L solution of sulfuric acid, g; M - mass of the sample, g [7].

The arithmetic mean of the results of five parallel analyses is taken as the test result. Calculations are performed to the third decimal place, and the result is rounded to the second decimal place.

The mass fraction of nitrogen in the dry matter of the sample (X₃) as a percentage is calculated by the formula:

                                                                   (2)

Х1 - mass fraction of nitrogen in the test sample, %; W - moisture content in the test sample, %.

The mass fraction of protein (Y) as a percentage was calculated using the following formula:

Y = K × X₁                                                                    (3)

where K is the nitrogen transfer coefficient to protein, equal to 6.38 in cases with average fat content.

The amount of nitrogen and proteins in 4 different samples of cheese prepared on the basis of experimental studies was studied at the Institute of Bioorganic Chemistry named after Academician A.S. Sadykov of the Academy of Sciences of Uzbekistan. Table 1 shows the results of laboratory studies of nitrogen and proteins in cheese [6-7].

Table 1.

The results of laboratory studies of nitrogen and proteins in cheese

The nitrogen and protein content of the above 4 types of cheese samples was determined under laboratory conditions, and in sample №2 brynza the nitrogen content is 3.67% and the protein content is 23.42%. This sample is the product brynza proposed by the author, and with the help of this vibration device, it was pressed and shaped, and the water content in it was minimized to the maximum extent. Also, the use of a vibration device in the pressing and shaping process of brinza gave a more effective result compared to other methods. The resulting final product is suitable for use in the food industry [7-8].

Conclusion

In conclusion, it can be said that 4 different brynza samples were obtained, the amount of nitrogen and protein in their composition was determined under laboratory conditions, and the amount of nitrogen in the brynza sample № 2 was 3.67%, and the amount of protein was 23.42%. In the process of preparing this sample of brynza, it is necessary to carry out the pressing process of the product quickly, in the end, the amount of moisture in the product should be low, when milk is accepted as a raw material, it is necessary to conduct laboratory tests to check the content of components in the composition and be under constant control. The second sample of the brynza product, which was pressed and shaped using a vibratory device, proved that the moisture content in the product was reduced to the maximum extent and the degree of single release of protein substances with the serum was reduced.

References:

1. J.Safarov, Sh.Sultanova, Z.Ergasheva, Y.Cahyana, A.Aït-Kaddour, M.Najafli, Q.Mukhiddinov Development of dry matter content of the main components of whey // AIP Conf. Proc. 2025 y, pp. 030026-1 - 030026-5. https://doi.org/10.1063/5.0306195.
2. Sh.Sultanova, Q.Mukhiddinov, J.Safarov, D.Alimova, A.Hassoun, M.Nasirova, Z.Ergasheva, B.Jumaev Determination of some characteristics of traditional cheese and evaluatıon of evaluated cheese to food safety // AIP Conf. Proc. 2025 y, pp. 030028-1 - 030028-7 https://doi.org/10.1063/5.0306235.
3. Mukhiddinov Q.A., Rakhimov A.M., Safarov Dj., A Aït-Kaddour., Sultonova Sh. Investigation of the process of molding, pressing and salting hard and soft cheeses. // IOP Conference Series: Earth and Environmental Science AEGIS 2022. C 2-10. doi.org/ 10.1088/1755-1315/1076/1/012060.
4. Ergasheva Z.K., Safarov J.E., Sultanova Sh.A. Mathematical modelling of inulin drying and extraction processes. 2022 E3S Web of Conferences ISSN 25550403 Doi 10.1051/e3sconf/202340103047
5. Ergasheva Z.K., Sultanov S.A., Saparov J.E. Analysis of dairy whey food functional modules based on resource-saving technologies. 2023 IOP Conference Series: Earth and Environmental Science 1231(1),012042 doi 10.1088/1755-1315/1231/1/012042
6. Mukhiddinov Q., Alimova D.K., Safarov J., Sultonova Sh., A Aït-Kaddour. Determination of Protein content in Cheese Products. // IOP Conference Series: Earth and Environmental Science. AEGIS 2021 C. 3-5. doi.org/10.1088/1755-1315/868/1/012046.
7. Ergasheva Z.K., Rakhmanova T.T., Abhijit Tarawade, Sultonova Sh.A., Safarov J.E. Investigation of the drying process of moist materials under convective heat input conditions. AEGIS-2022 IOP Conf. Series: Earth and Environmental Science 1076 (2022) 012058 IOP Publishing doi:10.1088/1755-1315/1076/1/012058
8. Dadaev Gani, Sultanova Shakhnoza, Safarov Jasur, Mukhiddinov Qobiljon. Calculation of the drying process of dietary materials in solar dryers. // E3S Web of Conferences 434, 01035 (2023. doi.org/10.1051/e3sconf/202343401035.