In this study, five different set type yogurt with vegetable purees, namely as control (K), yogurt with pumpkin (YBK), yogurt with carrot (YHA), yogurt with green peas (YBE) and yogurt with zucchini (YYK) were produced. The viable cell counts of S. thermophilus and L. delbrueckii subsp. bulgaricus were increased as a result of the ability of dietary fiber to stimulate their growth which is present in yogurt as puree. Vegetable puree addition had a noticeable effect on pH, titratable acidity, whey separation, sensory properties as well as textural attributes such as firmness, cohesiveness, consistency and viscosity index in yogurt. The highest viscosity index, consistency and firmness were observed in yogurt with the carrot puree, while the samples with zucchini presented the less compact structure and textural properties. As a result the present work showed that all the vegetable puree used had a beneficial role to improve textural properties of set type non-fat yogurt and could be used for the development of dairy products with functional ingredients.

In this study, microbial transglutaminase (MTGase) enzyme was used to produce yogurt from camel milk. It was reported that camel milk is rich in antimicrobial substances such as lysozyme, lactoperoxidase, lactoferrin and immunoglobulins, which prevent the production of yogurt from camel milk. With the advances in enzymology, it has been suggested that using enzymatic modifications to improve the functional properties and nutritional value of proteins may be effective in the production of yogurt from camel milk. For this purpose, the protein content of camel milk was increased by 6.2% with the addition of sodium caseinate, whey protein concentrate and micellar casein powder. MTGase enzyme was used at concentrations of 3 U and 6 U and the enzyme and the starter culture were added into the camel milk at the same time after that it was left for fermentation. Viscosity, pH and titratable acidity (as lactic acid, %) analyses were performed every hour during fermentation. The increase in viscosity formed as a result of cross-linking with the addition of MTGase enzyme, and the cross-linking formed were determined by decreasing the monomer band intensity of protein fractions with SDS-PAGE. It was found that the higher the MTGase concentration the higher the crosslinking reactions between the amino acids and the higher was the relative viscosity. In addition, the number of yogurt bacteria was determined on both M17 agar and MRS agar to investigate whether yogurt bacteria grow in camel milk and whether their growth is affected by the MTGase enzyme. As a result of the analysis, it was determined that the addition of MTGase enzyme has no suppressive effect on the growth of bacteria.