PROSPECTS OF THE USE OF LАСTOBACILLUS CASEI IN THE PRODUCTION OF CHEESE WITH A REDUCED MATURATION PERIOD

Abstract

Subject of research. In the production cycle of obtaining natural cheeses, a significant period of time is ripening. Its duration depends on the type of cheese and can take from several weeks to several months. During ripening, the most important role is played by the transformations associated with the splitting of proteins – proteolysis reactions, as a result of which various substances appear that determine the consumer characteristics of the final product. Recently, in view of economic factors, much attention is paid to the accelerated ripening of cheese. The problem of the production of cheeses with a shortened ripening period is to create conditions under which proteolysis reactions would take place more intensively, but without the appearance of bitter peptides, which are usually formed during excessive primary proteolysis. Purpose. Investigate the influence of lactic acid bacteria Lасtobacillus casei (L. casei) on the technological process of production and ripening of cheese and the organoleptic indicators of the target product; to evaluate the prospects of using this method and strain as an additional culture that shortens the ripening period of cheese. Methods. According to the technology of hard rennet cheeses with a low temperature of the second heating (ripening period of 40 days at a temperature of 10÷12 °С), two variants of cheese were produced: the experimental one, to which an additional culture – L. casei was added simultaneously with the sourdough, with the calculation that the number of cells of the strain in of the milk mixture was 1×105 CFU/cm3, and the control cheese containing only sourdough. Microbiological and biochemical analyzes were performed according to standardized methods. The following were determined: the total number of lactic acid bacteria and lactobacilli; active acidity and mass fraction of moisture in cheese; content of total, soluble and non-protein nitrogen (Kjeldahl method); amino acid composition. Biochemical studies were carried out after pressing and at the end of cheese ripening. The organoleptic evaluation of the cheese was carried out on the 40th day of ripening on the 100 bal scale in accordance with DSTU 4421:2005. Results. The use of L. casei as an additional culture deepened the proteolytic reactions, as a result of which the content of soluble protein cleavage products increased. At the end of ripening, the experimental cheese contained a higher content (%) of soluble (23.36±0.23) and non-protein nitrogen (16.54±0.20) compared to the control (20.47±0.21 and 13.21±0, 21, respectively), including short-chain peptides and free amino acids, which form the taste and consistency of cheese. The amino acid profile of the experimental cheese was characterized by a higher content of amino acids and contained cystine and threonine, which were not detected in the control. Compared to the control cheese, the experimental cheese had a richer taste range, a more pronounced aroma and a softer texture, due to which it was evaluated at 91 points, while the control - at 87 points. Scope of research results. Adding an additional culture at the same time as the sourdough starter is a promising way to shorten the ripening period of cheese, and the L. casei strain is suitable for such use. The research results will be used during the development of new cheese technologies.