FREE FAT IN MILK AND CHEESE PRODUCTS: INFLUENCE ON QUALITY

The theoretical and practical aspects of the formation of free fat in milk, cheese and cheese products with vegetable fats are considered. The amount of free fat in milk depends on the integrity of the fat globules membranes, which are affected by: ineffective emulsification of fat during the synthesis of milk in the cow’s udder (authentic fat) and physic-mechanical factors in the milk processing after milking (destabilized fat). Free fat, primarily subjected to oxidative processes and lipolysis, reduces the quality and ability to store milk. For cheese products, the presence of free fat, available for lipolysis and oxidation, is a prerequisite for obtaining high-quality products. Characteristics of the production of cheese products with vegetable fats, providing for the preliminary emulsification of vegetable fat in skim milk, contribute to the formation of denser membranes on the surface of fat globules, consisting mainly of casein micelles and whey proteins. This is the reason for the formation of a more closed structure of the fat phase with low availability of fat for enzymes and oxidizing agents. The low availability of fat in the structure of cheese products with vegetable fats is one of the factors that worsen their organoleptic characteristics. In order to increase the amount of available fat in the production of cheese products with vegetable fats, it is advisable to use additional enzyme preparations or cultures of microorganisms that activate proteolysis and lipolysis.The theoretical and practical aspects of the formation of free fat in milk, cheese and cheese products with vegetable fats are considered. The amount of free fat in milk depends on the integrity of the fat globules membranes, which are affected by: ineffective emulsification of fat during the synthesis of milk in the cow’s udder (authentic fat) and physic-mechanical factors in the milk processing after milking (destabilized fat). Free fat, primarily subjected to oxidative processes and lipolysis, reduces the quality and ability to store milk. For cheese products, the presence of free fat, available for lipolysis and oxidation, is a prerequisite for obtaining high-quality products. Characteristics of the production of cheese products with vegetable fats, providing for the preliminary emulsification of vegetable fat in skim milk, contribute to the formation of denser membranes on the surface of fat globules, consisting mainly of casein micelles and whey proteins. This is the reason for the formation of a more closed structure of the fat phase with low availability of fat for enzymes and oxidizing agents. The low availability of fat in the structure of cheese products with vegetable fats is one of the factors that worsen their organoleptic characteristics. In order to increase the amount of available fat in the production of cheese products with vegetable fats, it is advisable to use additional enzyme preparations or cultures of microorganisms that activate proteolysis and lipolysis

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

Ферментативный протеолиз при преобразовании молока в сыр

The transformation of milk into cheese occurs under the influence of many physicochemical, biochemical and microbiological processes, among which proteolysis plays a very important role. Proteolysis belongs to the most complex type of irreversible post-translational modification of proteins. Enzymatic proteolysis catalysts at different stages of cheese production are native milk enzymes, exo- and endopeptidases of starter and non-starter microorganisms, and milk-clotting enzymes. The article presents a brief overview of modern ideas about the properties, mechanism of action and specificity of the main representatives of enzymes that hydrolyze milk proteins at the stages of preparing milk for coagulation, during rennet coagulation and subsequent maturation of cheeses. These include the plasmin system of milk, enzymes of psychrotrophic bacteria and lactic acid microorganisms that enter milk both accidentally (non-starter microflora) and planned in the form of starter cultures from specially selected strains. Milk-clotting enzymes, having fulfilled their main function — milk coagulation — partially pass into cheese and, along with enzymes of starter microorganisms and plasmin, participate in proteolytic processes during cheese ripening. It is generally accepted that proteolysis in ripening cheeses is the most significant biochemical process that affects the formation of taste, aroma and texture along with lipolysis and glycolysis. The combination of proteolysis products (peptides, amino acids, amines, etc.) is individual for different types of cheese and varies depending on the technological parameters of production, including the duration of maturation. Proteolysis in cheeses has been studied by many scientists in various aspects. This review supplements the known information with new information, without claiming to be comprehensive.Преобразование молока в сыр происходит под влиянием множества физико-химических, биохимических и микробиологических процессов, среди которых протеолизу отводится очень важная роль. Протеолиз относится к наиболее сложному типу необратимой посттрансляционной модификации белков. Катализаторами ферментативного протеолиза на разных стадиях производства сыра являются нативные ферменты молока, экзо- и эндопептидазы заквасочных и незаквасочных микроорганизмов, молокосвертывающие ферменты. В статье представлен краткий обзор современных представлений о свойствах, механизме действия и специфичности основных представителей ферментов, гидролизующих молочные белки на стадиях подготовки молока к свертыванию, во время сычужного свертывания и последующего созревания сыров. К ним относятся плазминовая система молока, ферменты психротрофных бактерий и молочнокислых микроорганизмов, попадающих в молоко как случайно (незаквасочная микрофлора), так и планируемо в виде заквасок из специально подобранных штаммов. Молокосвертывающие ферменты, выполнив свою основную функцию — свертывание молока,— частично переходят в  сыр и  наряду с  ферментами заквасочных микроорганизмов и плазмином участвуют в протеолитических процессах при созревании сыра. Общепризнано, что протеолиз в созревающих сырах является наиболее значимым биохимическим процессом, влияющим на формирование вкуса, аромата и консистенции наряду с липолизом и гликолизом. Сочетание продуктов протеолиза (пептидов, аминокислот, аминов и др.) индивидуально для разных видов сыров и меняется в зависимости от технологических параметров изготовления, в том числе от продолжительности созревания. Протеолиз в сырах исследовался многими учеными в различных аспектах. Этот обзор дополняет известные сведения новой информацией, не претендуя на всеобъемлемость

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)

Efficacy of a Relaxation Scenario in Virtual Reality for the Comorbid Symptoms of Anxiety and Asthenia in a General Hospital Setting: A Pilot Comparative Randomized Open-Label Study

BACKGROUND: Patients in general hospitals often display concomitant signs of mental maladjustment: low mood, anxiety, apathy, asthenia, all of which can have a negative impact on the course of the underlying disease and the recovery process. One of the non-pharmacological approaches that has gained wider acceptance in medical practice in recent years is the use of procedures based on virtual reality. AIM: Assess the efficacy of the new domestic, virtual reality application Flow as relates to symptoms of anxiety and asthenia in patients undergoing inpatient treatment. METHODS: The study was open-label and had a comparison group; the patients were assigned to the experimental or control group using a randomization table. The patients were assessed using the Spielberger State Anxiety Inventory; the Fatigue Symptom Rating Scale; the Well-being, Activity, Mood questionnaire; the Depression Anxiety Stress Scale; and the Clinical Global Impression Scale. Physical parameters were measured before and after each virtual reality session. The obtained data were statistically processed. RESULTS: The study involved 60 patients. In 40 patients, the treatment program included a course of five daily relaxation sessions in virtual reality; the control group consisted of 20 patients, who were treated in accordance with the usual practice of the institution. The addition of virtual reality sessions to the standard treatment course yielded significant advantage in terms of affective symptoms reduction in patients both after a single session and as a result of undergoing the full course, and several days after its completion. The patients in the experimental group also showed a significant decrease in blood pressure after the sessions, and this was most pronounced in individuals who initially had elevated and high blood pressure. CONCLUSION: The use of relaxation program courses in the virtual reality application Flow is an effective and promising means of non-pharmacological care for non-psychiatric inpatients showing symptoms of anxiety, apathy, depressive mood, as well as hypertension

Рисунок в сырах: причины образования и методы оценки

The results of scientific research of the process of eyes formation in cheeses depending on the molding method and modes of pressing the cheese mass; the type of gassing microorganisms that make up the starter culture; rheological properties of curd; the presence in the cheese mass of “germs” — the centers of the formation of eyes — are considered. It is noted that the most studied in terms of the formation of the pattern are large cheeses of the Emmental or Swiss type with eyes up to 3 cm in diameter, which can be easily estimated by calculating their quantity and volume. For this, there are methods for visualizing eyes in the volume of cheese: X-ray, computed and magnetic resonance imaging, ultrasound and acoustic sounding. The least studied is the process of pattern formation in cheeses like Tilsiter and Russian, molded in bulk, with a large number of irregular, angular eyes. In connection with the observed tendency to the loss of the distinctive features of this type of cheese (rare, insufficiently pronounced eyes), great importance is attached to objective methods for assessing the pattern in these cheeses as one of the most important indicators of the product quality. Since computed tomography, X-ray and magnetic resonance imaging are methods that require expensive equipment, the need for a simpler procedure, suitable for production laboratories of cheesemaking enterprises, is justified for use in routine examinations. Based on the assumption that cheeses with a frequent pattern of angular, irregular shape can be considered as porous bodies, an assumption was made about the advisability of developing a method for measuring the porosity coefficient, which could supplement the organoleptic assessment of the pattern with an objective indicator that would allow the rejection of cheeses on this basis.Рассмотрены результаты научных исследований процесса образования глазков в сырах в зависимости от способа формования и режимов прессования сырной массы; вида газообразующих микроорганизмов, входящих в состав закваски; реологических свойств сырной массы; наличия в сырной массе «зародышей» — центров формирования глазков. Отмечено, что наиболее изученными в части формирования рисунка являются крупные сыры типа эмментальского или швейцарского с глазками диаметром до 3 см, которые легко можно оценить, подсчитав их количество и объем. Для этого существуют методы визуализации глазков в объеме сыра: рентгенография, компьютерная и магнитно-резонансная томография, ультразвуковое и акустическое зондирование. Наименее изученным остается процесс образования рисунка в сырах типа тильзитера и российского, формуемых насыпью, с большим количеством глазков неправильной, угловатой формы. В связи с наблюдаемой тенденцией к утрате отличительных признаков сыров этого типа (редкие, недостаточно выраженные глазки) придается важное значение объективным методам оценки рисунка в этих сырах как одного из важнейших показателей качества продукта. Так как компьютерная томография, рентген и магнитно-резонансная томография являются методами, требующими дорогостоящего оборудования, для использования в рутинных исследованиях обоснована необходимость в более простой процедуре, пригодной для производственных лабораторий сыродельных предприятий. Исходя из допущения, что сыры с частым рисунком угловатой, неправильной формы можно рассматривать как пористые тела, сделано предположение о целесообразности разработки метода измерений коэффициента пористости, который мог бы дополнить органолептическую оценку рисунка объективным показателем, позволяющим проводить отбраковку сыров по этому признаку