Biochemical Transformations of Lipide and Carbohydrat-Protein Nano Complex in Liquid Foodstuff

Abstract The process of enzymatic hydrolysis of dairy whey at presence of a polyfermental preparation pancreatin was investigated. The process of hydrolytic transformations of dairy proteins, fats and carbohydrates in comparison of a parallel estimation of changes of the sizes of the lipid, carbohydrates-protein formations which are being in nano region of area was studied

The formation of flavoring characteristics of meat products by changing the chemical composition of food compositions

The article presents the results of the study of changes in flavour characteristics when using corrective additives. Monosodium glutamate, ribotide, yeast extract and hydrolysate of vegetable soy protein were used as flavoring additives (FA). To assess the effect of composition of meat product recipe, as well as the method of FA‑introduction on taste intensity, the recipes of model meat systems with partial replacement of meat raw materials were used. Pork fat, soy protein and potato starch were used as meat substitutes. The effect of recipe composition on the content of non-volatile substances of aroma was accessed. It is shown that replacement of pork by pork fat in the recipe by 20–40% led to a sharp decrease in the concentration of aromatic substances and a decrease in intensity of taste of the finished product several times. The ways for taste correction using FA was studied. For this, a chopped semi-finished product — minced meat was prepared from chilled whole-muscle pork and 0.05% of each FA was added. It is shown that the dynamics of changes in the content of free amino acids is the most pronounced when using monosodium glutamate not as a mono-additive, but in compositions: monosodium glutamate with yeast extract and monosodium glutamate with ribotide. A pool of chemical compounds involved in the formation of taste and aroma of products was detected. The main components were derivatives of C6–C24 fatty acids, as well as a significant number of other biochemical compounds, mainly substituted amines, amides, alcohols and ketones, with a content ranging from 0.001 to 0.2 mg/kg. The results of organoleptic analysis showed that the most delicious and attractive samples were those containing monosodium glutamate with yeast extract and monosodium glutamate with ribotide

Generation of barcoded plasmid libraries for massively parallel analysis of chromatin position effects

The discovery of the position effect variegation phenomenon and the subsequent comprehensive analysis of its molecular mechanisms led to understanding that the local chromatin composition has a dramatic effect on gene activity. To study this effect in a high-throughput mode and at the genome-wide level, the Thousands of Reporters Integrated in Parallel (TRIP) approach based on the usage of barcoded reporter gene constructs was recently developed. Here we describe the construction and quality checks of high-diversity barcoded plasmid libraries supposed to be used for high-throughput analysis of chromatin position effects in Drosophila cells. First, we highlight the critical parameters that should be considered in the generation of barcoded plasmid libraries and introduce a simple method to assess the diversity of random sequences (barcodes) of synthetic oligonucleotides using PCR amplification followed by Sanger sequencing. Second, we compare the conventional restriction-ligation method with the Gibson assembly approach for cloning barcodes into the same plasmid vector. Third, we provide optimized parameters for the construction of barcoded plasmid libraries, such as the vector : insert ratio in the Gibson assembly reaction and the voltage used for electroporation of bacterial cells with ligation products. We also compare different approaches to check the quality of barcoded plasmid libraries. Finally, we briefly describe alternative approaches that can be used for the generation of such libraries. Importantly, all improvements and modifications of the techniques described here can be applied to a wide range of experiments involving barcoded plasmid libraries

Non3 is an essential Drosophila gene required for proper nucleolus assembly

The nucleolus is a dynamic non-membrane-bound nuclear organelle, which plays key roles not only in ribosome biogenesis but also in many other cellular processes. Consistent with its multiple functions, the nucleolus has been implicated in many human diseases, including cancer and degenerative pathologies of the nervous system and heart. Here, we report the characterization of the Drosophila Non3 (Novel nucleolar protein 3) gene, which encodes a protein homologous to the human Brix domain-containing Rpf2 that has been shown to control ribosomal RNA (rRNA) processing. We used imprecise P-element excision to generate four new mutant alleles in the Non3 gene. Complementation and phenotypic analyses showed that these Non3 mutations can be arranged in an allelic series that includes both viable and lethal alleles. The strongest lethal allele (Non3∆600) is a genetically null allele that carries a large deletion of the gene and exhibits early lethality when homozygous. Flies heterozygous for Non3∆600 occasionally exhibit a mild reduction in the bristle size, but develop normally and are fertile. However, heteroallelic combinations of viable Non3 mutations (Non3197, Non3310 and Non3259) display a Minute-like phenotype, consisting in delayed development and short and thin bristles, suggesting that they are defective in ribosome biogenesis. We also demonstrate that the Non3 protein localizes to the nucleolus of larval brain cells and it is required for proper nucleolar localization of Fibrillarin, a protein important for post-translational modification and processing of rRNAs. In summary, we generated a number of genetic and biochemical tools that were exploited for an initial characterization of Non3, and will be instrumental for future functional studies on this gene and its protein product

Study on acrylamide accumulation in the model system based on animal raw materials depending on thermal treatment regimes

The aim of the investigation was to study an effect of thermal treatment parameters on the content of reducing sugars, amino acids and acrylamide in the meat model system depending on the thermal treatment regime. The authors studied an influence of the reaction of melanoidine formation on the concentration of amino acids and reducing sugars at different thermal treatment regimes and established a decrease in the total amino acid content by 7 % upon the standard sterilization regime and by 11 % when increasing the temperature or duration of thermal treatment. It was found that at the same temperature with an increase in duration of thermal treatment up to 50 min., the acrylamide level increased by 1.6 times. Exposure of the model samples to a temperature of 120 °С for 50 min. had the highest effect on the level of acrylamide accumulation compared to the traditional sterilization regime of canned foods for child nutrition and the regime with an increased temperature of up to 130 °С. The obtained data will allow developing new meat products with the reduced content of unsafe components for nutrition in early childhood.The aim of the investigation was to study an effect of thermal treatment parameters on the content of reducing sugars, amino acids and acrylamide in the meat model system depending on the thermal treatment regime. The authors studied an influence of the reaction of melanoidine formation on the concentration of amino acids and reducing sugars at different thermal treatment regimes and established a decrease in the total amino acid content by 7 % upon the standard sterilization regime and by 11 % when increasing the temperature or duration of thermal treatment. It was found that at the same temperature with an increase in duration of thermal treatment up to 50 min., the acrylamide level increased by 1.6 times. Exposure of the model samples to a temperature of 120 °С for 50 min. had the highest effect on the level of acrylamide accumulation compared to the traditional sterilization regime of canned foods for child nutrition and the regime with an increased temperature of up to 130 °С. The obtained data will allow developing new meat products with the reduced content of unsafe components for nutrition in early childhood

Current trends in the synthesis of soluble and hot-melt polyimides

The work is devoted to a review of works published in recent years on the development of the chemical structure of soluble and hot-melt copolyimides, including a brief description of their synthesis and properties

АНАЛИТИЧЕСКИЙ КОНТРОЛЬ ПИЩЕВЫХ СИСТЕМ НА СОДЕРЖАНИЕ АКРИЛАМИДА МЕТОДОМ ВЫСОКОЭФФЕКТИВНОЙ ЖИДКОСТНОЙ ХРОМАТОГРАФИИ С МАСС-СПЕКТРОМЕТРИЧЕСКИМ ДЕТЕКТИ-РОВАНИЕМ

Currently, toxic substance – acrylamide is a serious problem for humans. Due to the natural presence of proteins and free amino acids in almost all food products, and during the processing of raw food materials, toxic acrylamide is formed at the elevated temperatures. The content of acrylamide in the Russian Federation is not standardized by the regulatory documents. However, at present, the following indicator is introduced into several regulatory documents of the Customs Union – the maximum permissible content of acrylamide in various types of food products. The analytical laboratories have a need to develop and implement a methodology for the reliable quantitative determination of acrylamide in complex food components with multipart composition, which can be used in the practical certification of testing laboratories. The authors have developed a method for the acrylamide determination in food products using the high-performance liquid chromatography with mass spectrometric detection in the monitoring mode of specified reactions. A procedure for preparing the samples for the analysis using GC with an electron capture detector and HPLC-MS/MS method is described. The optimal conditions for the determination of acrylamide by these methods are presented. The disadvantages of the method for the determination of acrylamide using the gas chromatography are discussed, namely, the low degree of extraction and the need for derivatization of acrylamide – a labile substance with an unsaturated chemical bond, which in most cases significantly complicates the analysis by traditional methods. The conditions of extraction and purification of the extract are selected to reduce the matrix effects. The effect of the reaction of melanoid formation on the acrylamide concentration is studied under the different heat exposure conditions and the optimal conditions for the reliable determination of the acrylamide content depending on the heat treatment of the raw materials and products were established. An assessment of the specificity, accuracy and correctness of the method has been carried out. It was shown that, in accordance with the developed method, acrylamide can be determined with an accuracy of 97.3–98.2% with its content at the level of 5–20 ng / ml. The degree of extraction of acrylamide was 82–91%. The limit of quantitative detection of acrylamide was 2 µg / kg.Keywords: acrylamide, safety, carcinogen, gas chromatography, HPLC with mass spectrometric detection(Russian)DOI: http://dx.doi.org/10.15826/analitika.2019.23.3.002A.V. Kulikovskii1, N.L. Vostrikova1, O.A. Kuznetsova1, A.A. Semenova 1, A.N. Ivankin2 1V.M. Gorbatov Federal Research Center for Food Systems of Russian Academy of Sciences, Russian Federation, 109316, Moscow, Talalikhina st., 262Bauman Moscow State Technical University, Russian Federation, 105005, Moscow, 5, 2nd Baumanskaya st.Токсичное вещество – акриламид представляет собой серьезную проблему для человека. Из-за естественного наличия практически во всех пищевых продуктах белков и свободных аминокислот, в ходе технологической обработки пищевого сырья при повышенных температурах происходит образование токсичного акриламида. Содержание акриламида в Российской Федерации в нормативных документах не нормируется, однако в настоящее время в ряде  регламентных документов Таможенного союза вводится показатель – предельно допустимое содержание акриламида в различных видах пищевых продуктов. У аналитических лабораторий существует потребность в разработке и внедрении методологии достоверного количественного определения содержания акриламида в сложных по компонентному составу объектах пищевого назначения, которая  может быть использована в практической сертификации  испытательных лабораторий.  Авторами разработана методика определения акриламида в пищевых продуктах методом высокоэффективной жидкостной хроматографии с масс-спектрометрическим детектированием в режиме мониторинга заданных реакций. Описана методика подготовки проб к анализу методом ГХ с электронозахватным детектором  и методом ВЭЖХ-МС/МС. Представлены  оптимальные условия определения акриламида данными методами. Обсуждены недостатки методики определения акриламида с использованием классической газовой хроматографии, а именно низкая степень извлечения и необходимость дериватизации акриламида – лабильного вещества с непредельной химической связью, наличие которой в большинстве случаев существенно осложняет анализ традиционными методами. Подобраны условия экстракции и очистки экстракта для снижения матричных эффектов.  Исследовано влияние реакции меланоидинообразования на концентрацию акриламида при разных режимах теплового воздействия и установлены оптимальные условия достоверного определения содержания акриламида в зависимости от тепловой обработки сырья и продуктов. Проведена оценка специфичности, правильности и точности методики. Показано, что в соответствии с разработанным методом, акриламид может определяться с точностью 97.3–98.2 %  при его содержании на уровне 5–20 нг/мл. Степень извлечения акриламида составляла 82–91 %. Предел количественного обнаружения акриламида был равен  2 мкг/кг.Ключевые слова: акриламид, безопасность, канцероген, газовая хроматография, ВЭЖХ с масс-спектрометрическим детектированиемDOI: http://dx.doi.org/10.15826/analitika.2019.23.3.00

Prospects for the synthesis and application of copolyimides based on tetracarboxylic acid dianhydride mixtures

The process of obtaining copolyimides by polycondensation based on 3,6-diaminoacridine, 9,9-bis-(p-aminophenyl)fluorene, dianhydride of 2,2-bis-(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane and dianhydride of 3,3',4,4'-tetracarboxydifenyloxide are described. The main physico-chemical properties of the obtained products are discussed and the prospects for the use of these soluble and fusible products as a polymer base for the preparation of composite materials are shown

К ВОПРОСУ ОПРЕДЕЛЕНИЯ РАСТИТЕЛЬНЫХ ЖИРОВ В ПИЩЕВОЙ ПРОДУКЦИИ

Tightening control over the quality and safety of food products leads to an expansion of the list of standardized indicators and the regulatory framework of research methods. Despite the lack of established standards and requirements for fatty acid composition (FAC) of meat products and the content of vegetable fats in it, methods have been developed for determining FAC and vegetable fats. The presented approaches to sample preparation make it possible to extract analytes from a sample as quickly and efficiently as possible, and the capabilities of modern analytical equipment make it possible to determine even trace amounts. The lower limit of determination of vegetable fats is 1.0 mg / kg. Ionization by electron impact, in which the molecule of the analyte breaks down into characteristic daughter ions, as well as the use of a library of mass spectra exclude obtaining false or falsepositive results.Ужесточающийся контроль за качеством и безопасностью пищевой продукции приводит к расширению списка нормируемых показателей и нормативной базы методов исследований. Не смотря на отсутствие установленных норм и требований к жирно-кислотному составу (ЖКС) мясной продукции и содержанию в  ней растительных жиров, были разработаны методики определения ЖКС и  жиров растительного происхождения. Приведенные подходы к подготовке проб позволяют максимально быстро и эффективно экстрагировать из образца анализируемые вещества, а  возможности современного аналитического оборудования позволяют определять даже в  следовые количества. Нижний предел определения растительных жиров составляет от 1,0 мг/кг. Ионизация электронным ударом, при котором молекула определяемого вещества распадается на характерные дочерний ионы, а так же использование библиотеки масс-спектров исключают получение недостоверных или ложноположительных результатов

?2-Microglobulin Amyloid Fibril-Induced Membrane Disruption Is Enhanced by Endosomal Lipids and Acidic pH

Although the molecular mechanisms underlying the pathology of amyloidoses are not well understood, the interaction between amyloid proteins and cell membranes is thought to play a role in several amyloid diseases. Amyloid fibrils of ?2-microglobulin (?2m), associated with dialysis-related amyloidosis (DRA), have been shown to cause disruption of anionic lipid bilayers in vitro. However, the effect of lipid composition and the chemical environment in which ?2m-lipid interactions occur have not been investigated previously. Here we examine membrane damage resulting from the interaction of ?2m monomers and fibrils with lipid bilayers. Using dye release, tryptophan fluorescence quenching and fluorescence confocal microscopy assays we investigate the effect of anionic lipid composition and pH on the susceptibility of liposomes to fibril-induced membrane damage. We show that ?2m fibril-induced membrane disruption is modulated by anionic lipid composition and is enhanced by acidic pH. Most strikingly, the greatest degree of membrane disruption is observed for liposomes containing bis(monoacylglycero)phosphate (BMP) at acidic pH, conditions likely to reflect those encountered in the endocytic pathway. The results suggest that the interaction between ?2m fibrils and membranes of endosomal origin may play a role in the molecular mechanism of ?2m amyloid-associated osteoarticular tissue destruction in DRA