STUDY OF FATTY ACID COMPOSITION OF MILK FOR CHEESE PRODUCTION

The article shows that the studied samples of raw milk in terms of composition (mass fraction of fat, protein, lactose and milk solids-not-fat) met the criteria of suitability for cheese, and its physic-chemical properties (titratable acidity, density, freezing point) were within acceptable limits. Moreover, rennet sample corresponded to the first and second classes. It was proved that the number of spores of lactating fermenting microorganisms met the requirements for milk for the production of any kind of cheese. It was established that the fatty acid composition of raw cow’s milk used to produce cheeses at various enterprises varied significantly. The data indicate the variability of the content of all groups of fatty acids — low molecular weight, saturated, monounsaturated and polyunsaturated. As a result of gas chromatography studies using the chromatographic complex «Chromos GX-1000» with a flame ionization detector and a CP 88 quartz capillary column — Sil 88 for FAME100 m × 0.25 mm × 0.2 µm, it was found that the largest absolute fluctuations were for saturated (± 7.03 % of the average value) and monounsaturated fatty acids (± 3.77 % of the average value). Absolute fluctuations in the group of low molecular weight fatty acids amounted to ± 2.62 %, and in the group of polyunsaturated — ± 1.02 % of the average value. The calculation of the relative deviation showed that the most varied groups were the ones of low molecular weight fatty acids (± 28.40 rel.%) and polyunsaturated fatty acids (± 25.11 rel.%). At the same time, a relatively high content of certain fatty acids: myristoleic, palmitic, palmitoleic and low levels of stearic and oleic fatty acids, was revealed in individual milk samples.The article shows that the studied samples of raw milk in terms of composition (mass fraction of fat, protein, lactose and milk solids-not-fat) met the criteria of suitability for cheese, and its physic-chemical properties (titratable acidity, density, freezing point) were within acceptable limits. Moreover, rennet sample corresponded to the first and second classes. It was proved that the number of spores of lactating fermenting microorganisms met the requirements for milk for the production of any kind of cheese. It was established that the fatty acid composition of raw cow’s milk used to produce cheeses at various enterprises varied significantly. The data indicate the variability of the content of all groups of fatty acids — low molecular weight, saturated, monounsaturated and polyunsaturated. As a result of gas chromatography studies using the chromatographic complex «Chromos GX-1000» with a flame ionization detector and a CP 88 quartz capillary column — Sil 88 for FAME100 m × 0.25 mm × 0.2 µm, it was found that the largest absolute fluctuations were for saturated (± 7.03 % of the average value) and monounsaturated fatty acids (± 3.77 % of the average value). Absolute fluctuations in the group of low molecular weight fatty acids amounted to ± 2.62 %, and in the group of polyunsaturated — ± 1.02 % of the average value. The calculation of the relative deviation showed that the most varied groups were the ones of low molecular weight fatty acids (± 28.40 rel.%) and polyunsaturated fatty acids (± 25.11 rel.%). At the same time, a relatively high content of certain fatty acids: myristoleic, palmitic, palmitoleic and low levels of stearic and oleic fatty acids, was revealed in individual milk samples

IMPROVEMENT OF ORGANOLEPTIC INDICATORS OF CHEESE PRODUCTS BY CORRECTING FATTY ACID COMPOSITION OF FAT PHASE

The aim of the study was to establish the possibility of improving the organoleptic characteristics of cheese products by introducing butyric acid into the composition of the used vegetable fat composition. Cheese products made using two fat compositions consisting of refined, deodorized vegetable fats, including those modified by interesterification, were studied. The experimental fat composition contained in its composition additional butyric acid added to the composition of triglycerides. The study of cheese products was carried out in the process of ripening and storage for 120 days in comparison with cheese, the fat phase of which is represented by milk fat. It was found that the degree of proteolysis, estimated by the ratio of total water-soluble nitrogen to total nitrogen, does not depend on the nature of the fat in the protein matrix. Milk fat in cheeses is more subjected to lipolysis than vegetable fats in cheese products. The addition of butyric acid to the vegetable composition in an amount of 0.8% increased the acidity of the fat phase by 0.1 mmol/100 g. According to the assessment of organoleptic characteristics, cheese with milk fat had the most pronounced cheese flavor and aroma, cheese product without butyric acid in fat phase had the least pronounced ones. A cheese product with a fat composition containing added butyric acid was close to cheese with milk fat in terms of the severity of cheese taste, rheological characteristics and the spectrum of volatile flavoring substances. It is concluded that the taste and aroma of cheese products have a positive effect on adjusting the fatty acid composition of vegetable fat compositions by introducing butyric acid into their composition.The aim of the study was to establish the possibility of improving the organoleptic characteristics of cheese products by introducing butyric acid into the composition of the used vegetable fat composition. Cheese products made using two fat compositions consisting of refined, deodorized vegetable fats, including those modified by interesterification, were studied. The experimental fat composition contained in its composition additional butyric acid added to the composition of triglycerides. The study of cheese products was carried out in the process of ripening and storage for 120 days in comparison with cheese, the fat phase of which is represented by milk fat. It was found that the degree of proteolysis, estimated by the ratio of total water-soluble nitrogen to total nitrogen, does not depend on the nature of the fat in the protein matrix. Milk fat in cheeses is more subjected to lipolysis than vegetable fats in cheese products. The addition of butyric acid to the vegetable composition in an amount of 0.8% increased the acidity of the fat phase by 0.1 mmol/100 g. According to the assessment of organoleptic characteristics, cheese with milk fat had the most pronounced cheese flavor and aroma, cheese product without butyric acid in fat phase had the least pronounced ones. A cheese product with a fat composition containing added butyric acid was close to cheese with milk fat in terms of the severity of cheese taste, rheological characteristics and the spectrum of volatile flavoring substances. It is concluded that the taste and aroma of cheese products have a positive effect on adjusting the fatty acid composition of vegetable fat compositions by introducing butyric acid into their composition

Features of micro- and ultrastructure of low-fat butter and its low-fat analogues

The aim of the research was to study the features of the structure of low-fat butter and butter pastes, which, in terms of composition and properties, more fully meet the requirements of a healthy diet than high-fat types of butter. The objects of research were: butter with fat content of 72.5%; butter with fat content of 55% made with the addition of skimmed milk powder; butter of the same fat content with the addition of stabilizers based on guar and xanthan gums and emulsifiers based on monoand diglycerides of fatty acids; butter pastes with fat content of 45% with similar additives used to increase the stability of the process of butter formation and improve the texture. The microstructure was studied using an MBI-6 microscope, and the ultramicrostructure was studied using a Phillips electron microscope. In the first case, the sample was prepared by crushing the sample, in the second one — by the method of ultrafast freeze-fracture and etching. Researches have shown that the use of the introduced ingredients improves the homogeneity of the structure of the studied products. Due to the ability of milk proteins and stabilizers to retain moisture, it is more evenly distributed and well retained in the fat matrix of the product, formed from crystalline and liquid fat in the form of a continuous phase, which is confirmed by a sufficient penetration depth of the fat-soluble dye. Plasma droplets in butter with fat content of 72.5% and 55% are more isolated than in butter pastes, as indicated by the greater penetration depth of the water-soluble dye. The average diameter of isolated moisture droplets in low-fat products was 3.3–5.4 μm, and the average diameter of the fat globules that form the basis of the crystalline framework was 5.4–7.4 μm, depending on the composition of the product. For butter with fat content of 72.5%, the values of these indicators were 2.8 and 4.0 μm. The results of the study indicate the presence of differences in the sizes of structural elements, but at the same time confirm the uniformity of the structure of low-fat products, allowing them to be attributed to dispersions «water-in-oil»

Влияние изменений в жировой фазе на особенности формирования показателей качества полутвердых и твердых сыров

Cheesemaking is a complex process that involves  lactose metabolism, proteolysis and  lipolysis. The flavor bouquet  of ripening cheeses is formed  as a result of changes in all the  components of milk. The conditions of keeping and feeding  a ruminant, its type, breed,  as well as the  technological features of cheese production influence this  process. Milk fat  contributes to  the  formation of the  flavor  bouquet of cheese, which  undergoes separate changes in the  stage  of milk processing for cheese. We studied semi-hard cheeses — Dutch  and Vityaz and hard cheese — Italiko, made from the same raw milk using the microflora characteristic of these cheeses. The temperature  of the  second heating ranged from 39°C to 54°C, depending on the  type  of cheese. To assess  the  quality of cheeses, their physical and chemical composition and degree of maturity, organoleptic indicators and the content of volatile flavoring compounds, acid number, Reichert-Meissl number and  fatty acid composition of the  fatty phase of cheeses were determined. In comparative studies of cheeses, the features of the formation of their quality indicators, due to the composition and manufacturing technology, were revealed. They manifested themselves in the  flavor bouquet and texture of the  product, as well as in the  fatty acid composition of cheeses, confirming the importance of the fat phase in the quality formation of the studied cheeses during their production, ripening and storage. It has been  proven that even a slight  increase in the  acid number of fat during the  production of all cheeses contributes to the  further transformation of the  resulting free  fatty acids  into  volatile flavoring  compounds that take part  in the formation of the taste and aroma  of the finished product.Изготовление сыров  — это сложный процесс, который сопровождается метаболизмом лактозы, протеолизом и липолизом. Вкусовой букет созревающих сыров  формируется в результате изменений всех составных частей молока. На этот процесс влияют условия содержания и кормления жвачного животного, его вид, порода, а также технологические особенности производства сыра. Свой вклад  в формирование вкусового букета сыра вносит молочный жир, который в процессе переработки молока на сыр подвергается отдельным изменениям. Исследовали полутвердые сыры — Голландский и Витязь  и твердый сыр — Италико, изготовленные из одного и того же молока-сырья с использованием характерной для этих сыров микрофлорой. Температура второго нагревания составляла от 39 °C до 54 °C, в зависимости от вида  сыра. Для оценки качества сыров определяли их физико-химический состав и степень зрелости, органолептические показатели и содержание летучих вкусо-ароматических соединений, кислотное число, число Рейхерта-Мейссля и жирнокислотный состав жировой фазы  сыров. При сравнительных исследованиях сыров выявлены особенности формирования показателей их качества, обусловленные составом и технологией изготовления. Они проявились во вкусовом букете и консистенции продукта, а также в жирнокислотном составе сыров, подтвердив значимость жировой фазы  в формировании качества исследуемых сыров в процессе их выработки, созревания и хранения. Доказано,  что даже несущественное повышение кислотного числа  жира при выработке всех сыров  способствует дальнейшей трансформации образующихся свободных жирных кислот  в летучие вкусо-ароматические соединения, принимающие участие в формировании вкуса и аромата готового продукта

Технологические и методические аспекты производства низко- и безлактозных молочных продуктов

The features of technologies for low- and lactose-free dairy products, which provide for special operations to hydrolyze lactose or remove it using ultra- or nanofiltration followed by hydrolysis of the residual amount, are considered. Dairy products manufactured using these technologies in different countries as well as enterprises leading in this field of production are presented. The analysis of the methods used to determine the quantitative content of residual lactose in low- and lactose-free dairy products is carried out: enzymatic, HPLC, HPAEC-PAD, amperometric biosensors, Raman spectroscopy. Due to the dairy industry’s need for analytical methods for the determination of lactose in milk and dairy products with low- or lactose-free content, the AOAC Stakeholder Group on Strategic Food Analysis Methods approved Standard Performance Requirements for Biosensor Methods (SMPR®) 2018.009. These requirements were introduced for the quantitative determination of lactose in milk as well as in dairy and milk-containing products with a low or no lactose content. The biosensor method is recommended for use as the official first step of AOAC method. Additionally, it is advisable to use high performance liquid chromatography (HPLC) with mass spectrometric detection, as well as high performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) as an international standard method of analysis for the determination of lactose in milk with low- or lactose-free content.Рассмотрены особенности технологий низко- и безлактозных молочных продуктов, предусматривающие проведение специальных операций по гидролизу лактозы или удалению ее с помощью ультра- или нанофильтрации с последующим гидролизом остаточного количества. Представлена молочная продукция, изготовляемая по этим технологиям в разных странах, и предприятия, лидирующие в этой сфере производства. Проведен анализ методов, применяемых для определения количественного содержания остаточной лактозы в низко- и безлактозных молочных продуктах: ферментативные, ВЭЖХ, HPAEC-PAD, амперометрические биосенсоры, рамановская спектроскопия. В связи с потребностью молочной промышленности в методах анализа для определения лактозы в молоке и молочных продуктах с низким или безлактозным содержанием, группа заинтересованных сторон AOAC по стратегическим методам анализа пищевых продуктов утвердила Стандартные требования к эффективности биосенсорных методов (SMPR®) 2018.009. Данные требования введены для количественного определения лактозы в молоке, а также в молочных и молокосодержащих продуктах с низким содержанием лактозы или ее полным отсутствием. Биосенсорный метод рекомендован для использования в качестве официального метода AOAC первого действия. Наряду с этим целесообразно использовать в статусе международного стандартного метода анализа для определения лактозы в молоке с низким или безлактозным содержанием высокоэффективную жидкостную хроматографию (ВЭЖХ) с масс-спектрометрическим детектированием, а также высокоэффективную анионообменную хроматографию с импульсным амперометрическим детектированием (HPAEC-PAD)

Влияние температуры замораживания и хранения на стабильность жировой эмульсии в сливках

The article presents the results of a study of frozen cream, the purpose of which was to assess the feasibility of using various freezing and storage modes to obtain a product with a stable fat phase. The objects of the study were cream samples of various fat contents (30%, 40% and 50%). Freezing was carried out at three temperature conditions (–50 °C, —25 °C and –18 °C) followed by storage for 4 months in refrigerators maintaining temperatures of –18 °C, —25 °C and –50 °C. Before and after low-temperature treatment, the state of the fat phase of the cream and the size of ice crystals were assessed using a microscopic method. Destabilization of fat dispersion was determined by the content of destabilized fat. It has been confirmed that with increasing mass fraction of fat in cream, the degree of destabilization increases. The amount of destabilized fat in cream samples with 30, 40 and 50% fat content before freezing was 14.3%, 20.0% and 32.0%, respectively. According to the research results, it has been revealed that when the freezing temperature decreases from –18 °C to –50 °C, there is no noticeable reduction in the amount of destabilized fat. The degree of destabilization decreased when cream was moved from lower to more gentle temperature conditions. At a storage temperature of –18 °C for cream previously frozen at –50 °C and –25 °C, the amount of destabilized fat in the cream was lower by 8.0–14.0% and 20.0–25.0%, respectively, in comparison with samples frozen and stored at the same temperature. When conducting microstructural studies, it has been revealed that freezing at a lower temperature with a change in storage temperature allows obtaining ice crystals with a smoother surface, which cause less damage to the membranes of fat globules.В статье представлены результаты исследования замороженных сливок, целью которого была оценка целесообразности применения различных режимов замораживания и хранения для получения продукта со стабильной жировой фазой. Объектами исследования являлись сливки различной жирности — 30%, 40% и 50%. Замораживание проводили при трех температурных режимах (минус 50 °C, минус 25 °C и минус 18 °C) с последующим хранением в течение 4 месяцев в холодильных камерах с поддержанием температур минус 18 °C, 25 °C и 50 °C. До и после низкотемпературной обработки оценивали состояние жировой фазы сливок и размер кристаллов льда микроскопическим методом. Дестабилизацию жировой дисперсии определяли по содержанию дестабилизированного жира. Было подтверждено, что с увеличением массовой доли жира в сливках степень дестабилизации возрастает. Количество дестабилизированного жира в сливках 30, 40 и 50%-ной жирности до замораживания составляло 14,3%, 20,0% и 32,0% соответственно. По результатам исследований было выявлено, что при снижении температуры замораживания с минус 18 °C до минус 50 °C не происходит заметного сокращения количества дестабилизированного жира. Степень дестабилизации уменьшалась при перемещении сливок с более низких в более щадящие температурные условия. При температуре хранения минус 18 °C сливок, предварительно замороженных при минус 50 °C и минус 25 °C, количество дестабилизированного жира в сливках было меньше соответственно на 8,0–14,0% и 20,0–25,0% в сравнении с образцами, замороженными и хранимыми при одной и той же температуре. При проведении микроструктурных исследований было выявлено, что замораживание при более низкой температуре с изменением температурного режима хранения позволяет получить кристаллы льда с более гладкой поверхностью, которые вызывают меньшее повреждение оболочек жировых шариков

Rb1.66Cs1.34Tb[Si5.43Ge0.57O15]·H2O, a New Member of the OD-Family of Natural and Synthetic Layered Silicates: Topology-Symmetry Analysis and Structure Prediction

Crystals of new silicate-germanate Rb1.66Cs1.34Tb[Si5.43Ge0.57O15]·H2O have been synthesized hydrothermally in a multi-component system TbCl3:GeO2:SiO2 = 1:1:5 at T = 280 °C and P = 100 atm. K2CO3, Rb2CO3 and Cs2CO3 were added to the solution as mineralizers. The crystal structure was solved using single crystal X-ray data: a = 15.9429(3), b = 14.8407(3), c = 7.2781(1) Å, sp. gr. Pbam. New Rb,Cs,Tb-silicate-germanate consists of a [Si5.43Ge0.57O15]∞∞ corrugated tetrahedral layer combined by isolated TbO6 octahedra into the mixed microporous framework as in synthetic K3Nd[Si6O15]·2H2O, K3Nd[Si6O15] and K3Eu[Si6O15]·2H2O with the cavities occupied by Cs, Rb atoms and water molecules. Luminescence spectrum on new crystals was obtained and analysed. A comparison with the other representatives of related layered natural and synthetic silicates was carried out based on the topology-symmetry analysis by the OD (order-disorder) approach. The wollastonite chain was selected as the initial structural unit. Three symmetrical ways of forming ribbon from such a chain and three ways of further connecting ribbons to each other into the layer were revealed and described with symmetry groupoids. Hypothetical structural variants of the layers and ribbons in this family were predicted