Evaluation of the effect of transglutaminase enzyme and beta-glucan on survival ofLactobacillus acidophilus and physicochemical and sensory properties of probiotic low-fat yogurt

In the last two decades’ desire to consume low-fat or fat-free dairy products, due to adverse effects on human health from the consumption of excess fat, has dramatically increased. Therefore, the use of Transglutaminase enzymes to improve the texture of low-fat yogurt is desirable. In order to better survival and growth of probiotic bacteria in yogurt, prebiotic compounds such as beta-glucan can be used. Therefore, the overall aim of this study was to investigation the effect of transglutaminase enzyme and beta-glucan on survival of Lactobacillus acidophilus and physicochemical, microbiological and sensory properties of the probiotic low-fat yogurt.For this purpose, different percentage of transglutaminase enzyme (0.01,0.014,0.018) and beta-glucan (0.005,0.01,0.01) in a single form and combined according to a completely randomized design were added to low-fat yogurt containing lactobacillus acidophilus microorganisms.Produced samples from the point of view pH value,titratable acidity, syneresis, probiotic bacteria count and organoleptic properties within 21 days of storage in 4 °C, were evaluated.According to the results, the type of sample (transglutaminase and beta-glucan) and storage timeevery week for 21 dayshad a significant effect on pH and acidity of the yogurt(p≥0.05).Increasing the concentration of beta-glucan and the transglutaminase enzyme, significantly increasedviability ofLactobacillus acidophilus in low-fat yogurt(p≥0.05).By increasing the concentration of the transglutaminase enzyme, syneresis of tested yogurts significantly decreased and by increasingthe concentration of beta-glucan, syneresis significantly increased. The yogurt samples containing the highest percentage of transglutaminase enzyme (0.018),had the best viability of probiotic and sensory properties from the point of view of evaluators. Also in mentioned samples the survival rate of probiotic bacteria was higher than other samples and consequently were selected as superior treatments.