Optimization of yogurt production and investigation of some properties of yogurt produced by microbial transglutaminase and two different starter cultures from goat milk

OOBJECTIVE:: The aim of this study is to investigate the effects of microbial Transglutaminase (mTGase) enzyme, different milk protein powders and two yogurt starter cultures on various properties of yogurts in the production of yogurt from goat milk. MATERIAL AND METHODS: The physical chemical, textural, sensory, aroma and microstructural properties of goat milk yoghurts produced according to the experimental designs created using the Response Surface Method were investigated. RESULTS: It was determined that while the relative viscosity value was at the highest level in yoghurts produced with mTGase concentration in the range of 3-4.78 U/g protein, the starter culture rate used for the desired pH, SH and lactic acid concentration was between 0.08-0.2%. As a result of the optimization, 12 different yoghurts were produced and it was determined that the texture increased with the increase in the enzyme concentration and the serum protein concentrate used in the storage analyzes made on them. In sensory analysis, the enzyme positively affected the appearance and structure, while taste and aroma suppressed the specific taste of yogurt. In addition, it was determined that the microstructure of yoghurts changed depending on the type of starter culture used and a more homogeneous appearance was obtained. CONCLUSION: While curd firmness and hardness occurred in yogurts produced by adding sodium caseinate and serum protein concentrate, 2 different yogurt starter cultures and mTGase, it also showed positive improvements in syneresis and water holding capacity during storage. While the enzyme used causes positive developments in the microstructure of yoghurts, it has also been determined that the use of excess enzymes suppresses the unique flavor of yoghurt.