Effect of using transglutaminase on physical, chemical and sensory properties of set-type yoghurt

This study was conducted in order to evaluate the effects of transglutaminase (TGase) addition on some properties of set-type yoghurts such as titratable acidity, lactic acid, tyrosine, viscosity, gel firmness, syneresis, aroma compounds, sensory analysis, and micro-structural properties. The enzyme was added to yoghurt-milk at different production steps (after homogenization, after pasteurization and together with starter culture addition) and two different incubation times (10 min and 1 h) were used. Five TGase treated yoghurt samples and control sample were analyzed on 1st, 10th, and 20th days of storage. TGase addition did not cause significant changes on chemical properties of yoghurts. However, enzyme addition after pasteurization increased the gel strength and decreased the syneresis. Results of electron microscope showed that enzyme addition led proteins to be distributed more evenly in gel network due to the formation of cross-links between proteins.