New determination method for the ratio of the relative proportions of ϰ-casein alleles in milk powder

Abstract

Introduction. High-quality dairy products depend on the properties of raw materials. Milk is the basic raw material for all dairy products. Its quality is subject to requirements of biological safety, and its physicochemical and technological properties comply with strict indicators. ϰ-casein gene is a basic milk protein. Its allelic variants affect milk productivity, as well as its composition and technological properties, e.g. cheeseability and heat resistance. The research objective was to develop a new method for determining the ratio of the relative proportions of selection-significant kappa-casein gene alleles in bulk cow’s milk powder by means of molecular genetics and bioinformation system. The method can help to test raw materials for further processing rationality.
 Study objects and methods. The research included a genetic analysis of samples of bulk whole milk powder, bulk powdered skimmed milk, and bulk raw milk. The developed method involved DNA extraction, combined PCR-RFLP technique, electrophoretic results, and analysis detection of information data using new mathematical algorithms and software.
 Results and discussion. The ratio of the relative proportions of the kappa-casein gene alleles in milk powder was determined using primer sets JK5 and JK3, as well as restriction endonuclease HinfI for PCR-RFLP analysis. The experiment showed satisfactory reproducibility and interpretation of the obtained data. The program provided a ratio calculation of the kappa-casein gene alleles relative proportions in the studied milk powder samples, expressed as a percentage of the A allele proportion with additional indication of the absolute and relative errors. It also placed the information block of the generated numerical indicators into the percentage scale.
 Conclusion. The developed methodology was implemented by a set of laboratory procedures. The new specialized program “Calculation of the relative proportions ratio of ϰ-casein alleles in bulk milk” is on open access. It provides a correct and prompt data interpretation, generated during the analysis of dry milk raw materials of bulk origin.

Influence of k-casein genotype on heat stability and cheese making properties of milk powder

“…Coloured amplifiers were applied to the wells of a 2 % agarose gel prepared by melting of 2 g of agarose (Biotechnology Grade, Amresco, USA) in 100 mL of Tris-acetate electrode buffer (500 mL 1 × TAE buffer, 15 μL 1 % ethidium bromide solution). Detection was carried out by horizontal electrophoresis using a SE-2 camera (Helikon, Russia) and an Elf-4 power supply unit (DNA-Technology, Russia) (Gilmanov et al, 2020).…”

“…Nevertheless, for the rational processing of dairy raw materials the vast majority of scientists consider appropriate to use the milk of cows with the dominance of A allele for k-casein gene for manufacturing of products undergoing high-temperature processing, and to send for cheese making the milk of cows with the prevalence of B allele due to high mass fraction of dry substances (due to the high fat and protein content in it) (Mahmoudi et al, 2020;Gilmanov et al, 2020).…”

Effect of CSN3 Gene Polymorphism on the Formation of Milk Gels Induced by Physical, Chemical, and Biotechnological Factors

“…Evaluation of the polymorphism of milk proteins by the CSN3 gene was performed by PCR-PDRF analysis of raw milk according to the method [33]. A total of 1.5 mL of the analyzed samples in Eppendorf-type tubes was centrifuged at 9800× g for 15 min using a CM-50 mini-centrifuge (Elmi, Riga, Latvia).…”