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Theory and practice of meat processing

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Vol 3, No 2 (2018)
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https://doi.org/10.21323/2414-438X-2018-3-2

4-21 285
Abstract

The paper presents the studies on the degree of raw fat extraction from meat systems by various methods. Relative differences in extraction methods are shown depending on the polarity of solvents used. Fat was extracted using the classical Soxhlet method, as well as two-step extraction. Specially prepared model systems were used as test samples including both simple and multicomponent mixtures in the form of meat-and-bone meal, bone meal, and meat-and-plant meal. It was found that when using non-polar solvents, a large amount of polar lipids was lost. The influence of the solvent on the degree of extraction for glycerides, phosphatides, free fatty acids and oxidation products was shown. A number of experiments are presented and the results are given on the degree of fat extraction using mixtures of organic solvents with mineral acid. The studies allowed to choose the best extraction method for each type of meat and meat-containing raw materials. Based on the results, methodical recommendations are proposed on the use of hydrophobic and hydrophilic solvents and their mixtures. Methods of lipid extraction from food products after alkaline and acid hydrolysis are considered. Examples of fat determination by instrumental methods (refractometry) are given. Classical methods for fat content evaluation are described (Randall method, Twisselmann method, and Rushkovsky method).

Contribution

All authors bear responsibility for the work and presented data. All authors made an equal contribution to the work. The authors were equally involved in writing the manuscript and bear the equal responsibility for plagiarism.

Conflict of interest

The authors declare no conflict of interest.

22-32 235
Abstract

Cattle carcasses of ritual slaughter (Halal) from the lateral and medial side were investigated in order to identify the indigenous strains of lactic acid microorganisms capable of producing bacteriocins. Only 14 strains, from 36 strains of microorganisms isolated from washings taken from carcasses, were used for further research and identified as lactabacilus. In the study of their bacteriocinogenicity by the method of two-layer agars of modified composition, high inhibitory efficiency was proved with respect to the growth of the pathogen Salmonella typhimurium, only 6 isolated strains of lactabacilus. The use of this method of evaluation will not only reveal the presence of the ability of the lactabacilus to produce bacteriocins, but also to study their antagonistic activity against many of the studied microorganisms, which are indicators of compliance with various modes of technological processes. The presence of such microorganisms in the meat will increase the shelf life of meat, due to the suppression of the growth of closely related lactabacilus, some of which are spoilage microorganisms, as well as the growth of opportunistic and pathogenic microflora. In addition, the use of lactabacilus with bacteriocinogenicity in the production technology of raw sausages will reduce the risk of production of unsafe products. Thus, the presence of indigenous lactabacilus in meat is an additional factor that ensures the flow of desired biochemical processes and the safety of raw smoked sausages.

Contribution

All authors bear responsibility for the work and presented data. All authors made an equal contribution to the work. Dagmara S. Bataeva developed scientific and methodological approaches to work, determined the scope of research, analyzed the data obtained, performed the narrative and corrected it after submitting to the editorial office. Olga V. Sokolova conducted a review and analysis of the literature, carried out the descriptive part Elena V. Zaiko selected research objects, carried out microbiological analysis. Victoria V. Pashkova carried out preparatory work and microbiological analysis. The authors were equally involved in writing the manuscript and bear the equal responsibility for plagiarism.

Conflict of interest

The authors declare no conflict of interest.

33-39 204
Abstract

With the help of the automated system for the classification of carcasses of pigs, AutoFOM ultrasound have been processed 56682 carcasses of slaughter pigs with an average carcass weight of 94.3 kg. The mass and yield of muscle tissue from the main cuts in the carcass is shown. Correlation coefficients between the mass and the content of muscle tissue in the carcass and the main (premium) cuts (ham, neck, shoulder, belly, and loin) were studied. It is shown how the increase in the weight of each of the cuts affects the content of muscle tissue in the carcass and in the cut. For example, it was found that when the weight of the belly is increased by 10 kg (from 6 to 16 kg), the percentage of muscle tissue from carcass is reduced by 3.3% (from 54.5 to 51.8%), which is approximately 0.33% for 1 kg of additional weight of the belly. With an increase in the weight of the loin from 4 to 14 kg, the yield of muscle tissue from the carcass on the contrary increased by 11.6%, i.е. 1.16% for each additional kg of loin weight. A value (in absolute and relative units) of the main cuts is given. The conclusion is made about the prospects of using the obtained data in the creation of a specialized terminal line of pigs, characterized by an increased content of weight of premium cuts in the carcass.

Contribution

All authors bear responsibility for the work and presented data. All authors made an equal contribution to the work. The authors were equally involved in writing the manuscript and bear the equal responsibility for plagiarism.

Conflict of interest

The authors declare no conflict of interest.

40-52 234
Abstract

One of the methods to evaluate the level of gene expression is a real-time quantitative polymerase chain reaction (qPCR). Interest in the study of molecular mechanisms of gene expression and its evaluation in prokaryotes is due to the lack of research on this issue and a number of methodological problems. The paper presents a study of gene expression mechanism in prokaryotes evidence from Aeromonas salmonicida AS1 gyrase B and collagenase genes. As a result of the research, Random primer and oligo (dT) primer (two 3’-terminal nucleotides of the primer complementary to stop codon nucleotides of the transcribed DNA sequence) with anchor and adapter of our own design were tested, which are used in the reaction of reverse transcription. The use of oligo (dT) primer became possible only after polyadenylation of extracted RNA using special poly-A polymerase kit. It is determined that the developed protocol of reverse transcription (RT) using oligo (dT) primer and adapter with certain sequence on its 5’-terminus designed for further annealing of the reverse primer during real-time PCR along with preliminary polyadenylation of RNA excludes specific amplification of the background genomic DNA. This technique may be applied in evaluating the expression level of low-expression genes when high background genomic DNA content is found in the RNA sample, e.g. at the end of logarithmic growth of prokaryotic cells.

Contribution

All authors bear responsibility for the work and presented data. All authors made an equal contribution to the work. Minaev M. Yu. developed scientific and methodological approaches to work, determined the scope of research, analyzed the data obtained, performed the narrative and corrected it in final. Makhova A.A. selected research objects, carried out RNA extraction, reverse transcription and PCR analysis, performed the narrative part. The authors were equally involved in writing the manuscript and bear the equal responsibility for plagiarism.

Conflict of interest

The authors declare no conflict of interest.



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ISSN 2414-438X (Print)
ISSN 2414-441X (Online)