Effect of egg and microbial lysozyme on the properties of İzmir tulum cheese

In this study, the effect of two different enzyme preparations, egg and microbial lysozyme on the physical, chemical and microbiological properties of Izmir Tulum cheese was investigated. In the first stage, lysozyme enzyme preparations were added to milk at specified rates (40 ppm for egg lysozyme; 10 ppm for microbial lysozyme) and in the second stage, cheese production was carried out using these rates. Six types of Tulum cheese were produced including raw milk and pasteurized milk control groups. Physical, chemical and microbiological analyses were conducted on various storage days (1st, 30th, 60th, 90th and 120th days). According to the research findings, both enzyme preparations did not affect the pH value of the cheeses. However, microbial lysozyme-added cheeses had lower levels of titratable acidity. In cheeses using egg lysozyme and microbial lysozyme, the dry matter contents were lower while the fat ratios were higher. The amount of soluble nitrogen in lysozyme-added cheeses was higher than in other cheeses. Among the free fatty acids, the amounts of palmitic acid and stearic acid were not affected by the lysozyme preparations or pasteurization of milk While free fatty acids increased during storage, they decreased on the last day of storage. A total of 30 volatile components were identified in cheese samples and lysozyme enzyme preparations did not affect the formation of fatty acids but increased the formation of butanoic acid methyl ester and reduced the formation of octanoic acid methyl ester. Microbiologically, lysozyme enzymes did not affect lactic acid bacteria but showed antifungal properties against yeast and mold formation and reduced coliform bacteria content. No spore-forming bacteria were detected. In conclusion, different lysozyme enzyme preparations had limited effects on the physical and chemical properties of cheese production but led to significant microbiological differences. Lysozyme enzymes can be used as natural antimicrobial agents in cheese production. This study evaluated the usability of both egg white-derived lysozyme and microbial lysozyme in cheese production.