The effect of microbial transglutaminase enzyme treatment and Persian gum on the physicochemical and color characteristics of low-fat stirred yogurt

Among the food products, yogurt is very popular due to its distinctive characteristics such as the presence of lactic acid bacteria and nutritional and therapeutic properties. In any case, consumption of high-fat yogurt can endanger health on the one hand, and on the other hand, reducing fat reduces the quality of the product. Therefore, this research was conducted with the aim of investigating the possibility of improving the characteristics of low-fat stirred yogurt using the treatment of microbial enzyme transglutaminase (MTG) and Persian gum (PG). Low-fat stirred yogurt samples were produced using levels of 0, 0.1 and 0.2% (w/v) of PG gum and levels of 0 and 0.015% (w/v) of MTG enzyme. The physicochemical characteristics and color values of the samples were evaluated during 14 days of storage in the refrigerator. Based on the results of this research, the addition of PG and MTG enzyme significantly reduced acidity and syneresis (p<0.05). Furthermore, the addition of gum increased lightness and redness and reduced yellowness. Although the enzyme treatment like PG increased the lightness and redness, it caused an increase in the yellowness of the yogurt. Storage time significantly decreased syneresis and lightness parameters and increased yogurt acidity and redness and yellowness indexes (p<0.001). In conclusion, the results of this research showed that by using transglutaminase enzyme treatment (0.015%) and adding Persian gum (especially 0.2%), low-fat stirred yogurt with acceptable physicochemical characteristics and color can be produced and the quality of low-fat stirred yogurt can be improved.