SELECTION OF LACTIC ACID BACTERIA FOR THE MANUFACTURE OF LOW-FAT RENNET CHEESE

Abstract

Cheeses produced using traditional technology usually contains 45 % ‑ 50 % of milk fat in dry matter, therefore they are classified as high-calorie foods and are not recommended to be included in the diet of people who need dietary nutrition. In the European countries, dietary low-calorie rennet cheeses are widely represented in the trade network, and in Ukraine such products are quite rare, expensive and usually of foreign production. Milk fat is an important structural and flavoring component of rennet cheeses and a significant decrease in its content in milk leads to a product of low consumer quality with problems such as unexpressed taste, coarse, rubbery consistency. In proportion to the decrease in the mass fraction of fat in the cheese, the disadvantages are more pronounced. The solution to this problem requires an integrated approach, which consists in the correction of technological methods for the production and maturation of cheese and the optimization of the composition of fermented microflora. It is possible to improve the sensorial characteristics of low-calorie cheeses by introducing into their structure exopolysaccharides (EPS) – high-molecular polymers synthesized by some strains of lactic acid bacteria (LAB). Research subject: biological and technological properties of LAB. The aim of this work is to search for strains of LAB with given physiological and biochemical characteristics for further use in the production of dietary rennet cheeses with a reduced mass fraction (MF) of fat. The common microbiological and technological research methods were used in the work. Research results. The expediency of using sucrose as the only source of carbohydrate nutrition for screening LAB with EPS-activity has been shown. Six strains of LAB identified as Streptococcus thermophilus, Lactobacillus bulgaricus, Lactobacillus plantarum and Leuconostoc mesenteroides were withdrawn from non-commercial fermented milk products and studied for their technological properties. In laboratory conditions, the expediency of using LAB with EPS-activity for the production of cheese with a reduced MF of fat has been confirmed. The use of new cultures LAB in the composition of the starter culture allowed increasing the moisture content in the cheese by (6.5‑8.3)% compared to the control and to improve its texture and taste. Scope of research results application. The use of LAB-producers of EPS will improve the consumer characteristics of rennet cheeses with reduced fat content, expand the domestic range of these products, increase their biological value, will have a positive effect on the health of people who need dietary nutrition, as well as all population groups.