Volume 2, Issue 2, 2014
In this paper, some results of studying the energy efficiency of the fast freezing of different varieties of blackcurrant berries in a fluidized-bed fast freezer were reported. A method of calculating the energy expenditures on the fast freezing of different varieties of blackcurrant berries in an air fast freezer was proposed. The energy expenditures on the circulation of air at a rate required to create fluidization were determined depending on the air temperature. The energy consumption in the production of artificial cold for the provision of required heat-withdrawing air medium temperatures was calculated. The performed studies were used as a basis to determine the energy-efficient regimes of the low-temperature treatment of blackcurrant berries in an air fast freezer and also the types of a refrigerating machine and a refrigerant, which provided the least energy-consuming fast freezing of blackcurrant berries.
An important strategic objective of the food industry is to meet the demands of all categories of the population in high-quality, biologically valuable, and safe food. At present, structured products based on dairy raw materials are commonly used. Food materials used to generate the necessary rheological properties or modify the existing properties for food systems that adjust or form the consistency of food products are referred to as structure-stabilizing agents. Both individual ingredients and complex mixtures thereof can be structure-stabilizing agents. The use of these agents contributes to an increase in the density and to the formation of a specific structure of the food product, which is retained even after heat treatment. In this study, the composition and properties of structure-stabilizing agents for products based on dairy raw materials have been analyzed. The following characteristics have been selected to examine: bulk density, viscosity, the fraction of undissolved residue, microvoid content, specific volume, specific surface area, and characteristic diameter. The dynamics of structural changes that occur during the interaction with the solvent have been analyzed from micrographs. The weight fraction of chemical elements (oxygen, nitrogen, carbon, sodium, chlorine) has been determined via analyzing the spectrophotometric profile.
The composition and properties of blood plasma obtained from slaughtered farm animals and intended for use in the manufacturing of foods for the prevention of oxygen deficiency (hypoxia) are analyzed in the present paper. The use of aerated functional products (oxygen cocktails) is an efficient approach to hypoxia prevention. Protein-based foaming agents are known to form the most stable foams. Porcine blood plasma is a rich source of high molecular weight proteins. A method of processing of the blood of farm animals using a centrifuge with the separation factor (Fr) of 2000 or lower is described in the present article. Fractional composition of blood proteins from farm animals is reported, the choice of porcine blood plasma as a foaming agent is justified, and data on the content and amino acid compositionof high molecular weight proteins from porcine blood plasma is presented.
Technological Features of the Use of Wild-Growing Raw Materials in the Production of Sour-Milk Beverages
This paper reviews the data on the development of the technologies of sour-milk beverages with the use of wild-growing raw materials. The general principles of the creation of preventive sour-milk beverages and the principal requirements to wild-growing raw materials used to enrich their composition are formulated. Tavolga syrup based on herbs, such as megasea (Bergénia crassifólia), meadowsweet (Filipéndula ulmária), and peppermint (Méntha piperíta), and also whey extract and syrup based on balm (Melissa officinalis) are used in the work. The main regularities of the formation of organoleptic, physicochemical, mechanostructural, and probiotic properties of the sour-milk products with the use of aqueous and whey extracts and syrups based on wild-growing raw materials are shown. The prospects and possibility of the application of curd whey, which extracts nutrients from plant raw material, in the production of enriched sour-milk products is demonstrated. The content of milk whey in a sour-milk product is from 5 to 30%. The use of Tavolga syrup excludes the addition of colorants, flavors, and stabilizers, reduces the energy expenditures due to a decrease in the baking time, inhibits the accumulation of lactic acid by starter cultures, and also suppresses the growth of opportunistic microflora during the storage of sour-milk beverages. The technologies of Tavolga phyto-fermented baked milk and phytoyoghurt and Melissa and Lesnoi kefir beverages are described, and the nutritional value of the new sour-milk beverages is shown, including their vitamin composition. The developed technologies of the listed sour-milk beverages are competitive, as confirmed by their relevance, scientific validity, and engineering, social, and economic profitability.
Results of biotechnological research on controlled hydrolysis of casein and production of peptide complexes are summarized in the present article. Selection of processing parameters and optimization of the conditions of enzymatic hydrolysis of milk proteins allowed for the development of a resource-efficient technology for the production of peptide complexes. Enzymatic hydrolysis of peptide bonds R1-CONH-R2 + H2O - R1COOH + NH2R2 was considered using the example of casein and a range of proteolytic enzymes (trypsin and chymotrypsin) belonging to the hydrolase class. Enzyme solution (0.1% m/v) was added to each protein solution so that the final enzyme-substrate ratio was 1:25, 1:50, or 1:100. The enzyme-substrate ratio of 1:50 was shown to be optimal, and the re-commended temperature and pH values were 50±1°С and 7.50±0.01, respectively. The degree of hydrolysis is one of the parameters characterizing the overall changes in the amino acid composition of proteins. Therefore, a time period of 12.00±0.05 h was chosen as the optimal duration of the hydrolysis process. Further research was focused on the analysis of peptide profiles using MALDI-TOF MS based on identification of peptide sequences. The studies have shown that casein hydrolysates are rich in biologically active peptide complexes. The detection of such complexes in hydrolysates of casein was the main result of the study. For example, the peptide β-casokinin (amino acid sequence Ala-Val-Pro-Tyr-Pro-Gln-Arg) is an inhibitor of angiotensin-converting enzyme.
This article is dedicated to the development of new nonfat dairy products and methods of improving the quality of low-calorie foods. Advantages and drawbacks of the consumer properties of nonfat dairy products are shown. Some carbohydrate and protein fat imitators are characterized. The advantages of protein fat imitators are shown that are able not only to increase the protein content but also to add a creamy flavor to nonfat products. Possible options of using whey protein microparticulates as fat imitators in the production of nonfat dairy products are considered. The research findings are given on the use of whey protein microparticulates in the production of dairy products with higher protein contents: curd products, sweetened condensed milk, and natural cheeses: thermal-acid, soft acid-rennet, and brined.
Technology of Alcohol Oxidase Production From Yeast Candida Boidinii for Use in Functional Foods Intended for Withdrawal Syndrome Alleviation
The present article considers the increasing popularity of beverages containing ethyl alcohol and fermentation products with the population of Russia. Statistical data show that alcoholic beverages with ethanol concentration exceeding 40 vol. % account for the largest share of the market. The development of a procedure for the production of alcohol oxidase from the yeast Candida boidinii is reported; the enzyme is intended for use in the manufacturing of functional foods for withdrawal syndrome alleviation. A procedure for the disruption of cell walls of the yeast Candida boidinii in a planetary ball mill PM 400 and methods for the removal of ballast substances reducing the catalytic efficiency and the specific activity of the enzyme preparation are presented.
Theoretical and Practical Aspects of the Development of a Balanced Lipid Complex of Fat Compositions
In the paper, the effect of the lipid complex in fats and oils on human organism and their role in physiology of nutrition are reviewed. Aspects of impairment of the nutritional status upon fat consumption, in particular, the excess consumption of saturated fats, trans-isomers of fatty acids, and cholesterol and the deficiency of polyunsaturated fatty acids and phospholipids, are discussed. Data on oil and fat in modern structure of nutrition are described. Aspects of the development of balanced fat compositions, accounting for normal physiological needs of modern people for lipids and their structural components, are reviewed. Data on the construction of fatty bases from milk fat, natural, and modified vegetable oils and fats providing for predetermined consumer properties of functional fatty milk products are presented.
Recently the Russian dairy industry has undergone large changes, predetermined by the increasing use of nondairy raw materials (vegetable fats and proteins, natural fruit and vegetable fillers, etc.). This is associated with the increased demand for new products that not only have traditional nutritive properties but also make up for the deficit of certain nutrients in the ration. Practically all types of dairy products can be combined with various vegetable components. This article attempts to solve the problem of creating healthy foods by considering natural ingredients and technological specifics of functional food production.
Screening and Identification of Pigmental Yeast Producing L-phenylalanine Ammonia-Lyase and Their Physiological and Biochemical Characteristics
The results of the analysis of DNA sequences encoding L-phenylalanine ammonia-lyase (PAL) synthesis, performed to obtain universal primers complementary to conserved regions of the pal gene, are presented in the article. The fragment of pal gene was amplified in organisms under study. Nucleotide sequence of the pal gene in microorganisms exhibiting L-phenylalanine ammonia-lyase activity was determined by DNA sequencing. The results of its comparison with the corresponding sequences of known species are presented. Phenotypic characteristics and biochemical properties of selected cultures were studied. An investigation aimed to choose a superproducer strain of L-phenylalanine ammonia-lyase was conducted. It was found that L-phenylalanine ammonia-lyase synthesis was the most active in the following strains: Aureobasidium pullulans Y863, Rhodosporidium infirmominiatum Y1569, Candida glabrata Y2813, Candida maltose Y242, Debaryomyces robertsiae Y3392, Rhodosporidium diobovatum Y1565, Rhodotorula lactose Y2770, Saccharomyces cerevisiae Y1127, Tilletiopsis washingtonensis Y1650, Torulopsis apicola Y566, Tremella foliacea Y1624, Rhodotorula rubra Y1193, and Debaryomyces castellii Y968. This allows recommending them for further research aimed to obtain the enzyme preparation of L-phenylalanine ammonia-lyase.
Analysis of the Structural and Mechanical Properties and Micromorphological Features of Polymeric Films Based on Hydrocolloids of Vegetable Origin Used for the Production of Biodegradable Polymers
Modern research and technology approaches to the production of biodegradable polymeric materials based on renewable resources have been reviewed. It has been found that films prepared of cellulose, chitosan, gelatin, polypeptides, casein, soy, wheat, corn, rice, and maize are being commonly used at present. The structural and mechanical properties and micromorphological features of hydrocolloids of vegetable origin promising for the production of biodegradable polymers—starches, pectins, carrageenans, and agar—have been studied. It has been determined that, with respect to strength and suitability for use in films of individual components, all the studied hydrocolloids can be arranged in ascending order as follows: starches, carrageenans, pectins, agar. According to analysis of the structural and mechanical properties of the films, it has been shown that the best parameters are found for the samples based on pectin P1 and agar A2. The breaking stress for these materials is 52 and 77 MPa, respectively. The breaking strain is 11.5 and 8.0%, respectively. Analysis of the micromorphology has revealed the formation of surface microdiscontinuities in the films based on high methoxyl pectins P1 and P4 and unmodified corn starch S3 and the formation of wavy folds in the case of the films of kappa-carrageenan C1; these folds are formed during drying and decrease the tensile strength of the respective films. The found features will be used in the development of technologies for the production of biodegradable polymeric materials based on hydrocolloids of vegetable origin with enhanced performance and processing characteristics.
The use of Molecular Genetic Markers and PCR for DNA Diagnostics in Raw Materials Derived From Fruit and Berries
A general description of molecular genetic markers is provided in the present article. The classification of DNA markers used for identification of raw materials of plant origin is presented. The most appropriate method for identifying raw materials derived from fruit and berries is chosen using study reports. The use of PCR for determining the quantitative and qualitative composition of the raw materials is considered. DNA regions used for PCR diagnostics of raw material derived from fruit and berries are characterized. The significance of amplification for a PCR test is outlined. The optimal PCR conditions have been selected and the advantages of this method have been revealed in the present study. Amplification profiles of DNA from the samples have been analyzed using different primers. Experiments with different primers allowing for identification of the raw material were carried out. The possibility of using a complex including a common gene and a variable gene for the identification of raw materials derived from fruit and berries has been considered. The sequence of DNA regions has been analyzed. The possibility of using a ribosomal RNA gene for generic and interspecific differentiation of DNA samples has been demonstrated. The significance of oligonucleotide primers and PCR product length for the reliability of the whole genotyping system has been elucidated. A scheme of PCR-based DNA profiling has been developed. Two types of the procedure were compared and the most appropriate type was chosen according to cost efficiency.
The article presents the results of the research on methods of identification and quantitative determination of prion proteins in biological samples and multicomponent mixtures based on them. Analysis of nucleotide sequence of DNA encoding the PRNP gene of the prion protein, including phylogenetic and comparative analysis of nucleotide sequences of normal and pathogenic prion protein in cattle, was performed. Oligonucleotide primers for amplification of the PRNP gene of pathogenic prion protein were designed and synthesized. The high specificity of the developed test system was confirmed.
Methods that simulate the fast refrigeration of foods on the basis of a model of adjustable heat sink according to the principle of programmed freezing are considered. In this case, a fast freezer is seen as a system of modules, each of which can independently ensure the necessary heat-sink conditions for the fast refrigeration process. The focus is made on the analysis of physicochemical processes that form the water crystallization front at the first freezing stage, taking into account the thermophysical specifics of organizing a multizone combined system of refrigeration supply. Test-bench studies were conducted to obtain the main regularities of fast freezing of single-piece packaged dairy products by the nitrogen + air combined method in a wide range of heat-exchange conditions. The fast freezer has two freezing zones with various temperatures, allowing an efficient distribution of energy costs and creating the optimal conditions for freezing and for the continuity of the technological cycle. A mathematical model has been developed on the basis of experimental data analysis to determine the main technological parameter, the duration of food refrigeration in a nitrogen + air combined two-zone fast freezer with adjustable heat sink. The integral characteristics of the mathematical model have been determined. The model´s adequacy to the real freezing process has been proved.
Cheeses are analyzed as vacuum drying objects. An experimental vacuum drier and its elements are schematized. The operating principle of the experimental setup is described. Moisture is demonstrated to be among the most important components of cheese. The physicochemical composition of cheeses is considered. The forms and energy of moisture binding in cheese are discussed. The hygroscopic and thermophysical properties of cheeses are reported. The kinetics of the vacuum drying of cheeses has been investigated. The vacuum drying of cheeses includes two stages: the drying rate is constant at the first stage and decreases at the second stage. The temperature curves of cheeses have been plotted in the temperature–moisture weight fraction coordinates. Drying curves in the heat load–time, temperature–time, and moisture weight fraction–time coordinates have been obtained and analyzed for various cheeses. Cheese drying rate curves have been constructed by graphical differentiation. The maximum cheese drying rates have been determined. Equilibrium moisture content values for cheese drying have been found. The cheese shrinkage ratio has been correlated with the thickness of the cheese bed being dried and with the shape and size of cheese pieces. Cheese shrinkage at both stages of vacuum drying proceeds uniformly. Raising the drying temperature above the prescribed temperature reduces the shrinkage ratio.
A stochastic model studying the formation and destruction of a dispersed protein gas–liquid system (foam) is proposed. The regularities governing the formation of dispersed systems strongly depend on the conditions of a chemical engineering or engineering process, and both the formation of a foam and the destruction of the obtained foam layer occur simultaneously in the process of foam generation. Since a necessary condition for the construction of a stochastic model is the availability of statistical data, which provide the estimation of the number of both forming and bursting bubbles, the method of such a calculation is of topical interest. The model enables the description of the process state at every time moment of the first cycle. One of the characteristics of a foam is its dispersion, so the random variable characterizing the number of bubble per unit volume is introduced to study the processes of foam formation. The mathematical expectation, dispersion, and also the foam destruction rate function are proposed as a basis for the calculation of foaming efficiency characteristics. Since the model is formalized by a set of differential equations, it can also be used in the simulation modeling of the foaming process. The first cycle of the formation and destruction of a protein foam has systematically been studied. The constructed stochastic model has allowed the mathematical expectation and dispersion of the number of protein foam bubbles per unit volume to be calculated at any time moment of gas saturation within the first cycle. It has been shown that the applied numerical solutions of the differential equations are in good agreement with the analytical solutions given by simple formulas convenient for engineering calculations. A method of estimating the model parameters has been developed. The proposed model has allowed the quantitative description of the foaming process both on average and by states. It has been established that the time of the formation of a protein foam in a rotor-stator device at specified process parameters is advisable to be limited by the moment, at which the highest foam destruction rate is attained.
The precise and objective estimation of the beginning of gelation in milk is topical for both laboratory studies and industrial dairy production. In this work, the principles of the thermographic method of monitoring milk coagulation are formulated. This method has evolved from the well-known hot-wire method; it is based on the measurement of the temperature difference between two thermometers, one of which is heated. Unlike the hot-wire method, the thermographic method can even be used in processes that require significant changes in milk temperature, for example, during heat–acid milk coagulation. Two basic designs of thermographic systems, using as thermometers either differentially connected thermocouple junctions or two identical thermistors connected as two legs of a bridge circuit, are described. In both cases, the temperature difference between the heated and unheated thermometers at about 0.5 W of thermal power supply is about 3°C for incoagulated milk and 8–10°C after clot formation. The qualitative agreement of the results of rheological and thermographic methods has been demonstrated. A thermographic research technique for heat–acid or heat–calcium milk coagulations has been developed. Within the effective viscosity model, the numeric solution of the problem of temperature field simulation in the vicinity of the heated thermometer has been obtained. On the basis of the simulation results, the possibility of studying structure formation in milk during its coagulation has been analyzed using the thermographic data. Experimental results obtained during thermographic research of milk coagulation are presented.
Sistemic Regularities in the Study and Design of Technological Complexes for the Production of Instant Peverages
This article is devoted to the state-of-the-art systemic approach to the analysis and synthesis of process flows for the production of instant polydisperse granular functional beverages. The distinctive feature of these studies is the methodological approach developed by Academician V.A. Panfilov, representing a quantitative description of the integrity level of a large production process in a technological complex, based on the results of its diagnostics and comprising sequential transition in studies from a system of technologies to a system of processes and form a system of processes to a system of apparatuses and machines. The definition of a technological system as an interrelated whole creates a certain logic and methodology of its qualitative and quantitative study and develops a system-centered opinion on production.
Biosensors are promising analytical tools applicable in clinical diagnostics, food industry, environmental monitoring, and other areas in which rapid and reliable analyses are needed. This review covers the basic types of biosensors and their designs and general operating principles. A classification of biosensors according to the type of transducer they involve and according to the nature of the biological entity used as the recognition element is presented. Methods of immobilization of biological components, namely, adsorption, microencapsulation, inclusion, cross-linking, and covalent binding are briefly characterized. The main areas of application of biosensors in the food industry—food safety and quality assessment, process monitoring, and others—are considered.