SCREENING AND RESEARCH OF PRODUCERS OF MILK-COAGULATING ENZYMES AMONG CULTURES OF HIGHER BASIDIOMYCETES

EDN: LFMEJT

Abstract

Milk-coagulating enzymes are widely used in the production of cheeses and fermented milk products, such as cottage cheese, yogurt, sour cream. The choice of the enzyme is determined by the yield and taste characteristics of the resulting product. At the same time, the most important characteristics of the enzyme are substrate specificity, the level of total milk-coagulating and proteolytic activity. Due to the shortage and high cost of rennet, enzymes obtained from mushroom cultures are practiced in the food industry. The aim of the work is to screen and study producers of milk-coagulating enzymes among cultures of higher basidial fungi. The article presents the results of research on the selection of producers of milk-coagulating enzymes. The highest indicator of milk-coagulating activity was found in the culture of Piptoporus betulinus (19.4 units/ml) compared to Hericium coralloides (13.4 units/ml), Hericium erinaceus (5.7 units/ml), Coprinus comatus (3.4 units/ml) and Grifola frondosa (3.2 units/ml). The composition of the nutrient medium for the cultivation of mycelium of fungi with the highest MCA has been established, which includes the following components, %: beet molasses (30), NH₄NO₃ (1.5), КН₂РО₄ (0.4), MgSO₄×7H₂O (0.05), distilled water (up to 1000 ml). It was found that micro- and ultrafiltration of culture fluid allows to increase the level of milk-coagulating activity of P. betulinus by 26.8 % and 96.4 %, H. coralloides by 13.4 % and 67.9 %, respectively. The ratio of milk-coagulating to proteolytic activity ranges from 298 to 568, which makes it possible to recommend a culture liquid for the development of an enzyme preparation used in cheese making.