Effect of Pullulan on Physicochemical, Microbiological, and Sensory Quality of Yogurts

Background: Pullulan can partially or completely replace starch or fat, thanks to which it can be used for the production of dietetic food. It allows you to maintain the desired consistency, and increases the viscosity of the product. Objective: Therefore, an attempt was made to produce yogurts with pullulan addition and determine the effect of its presence on the number of LAB, pH change, titratable acidity, and sensory quality of yogurts during storage at 4°C for 28 days. Method: The effect of addition of 0; 1.0 and 2.0 % w/v pullulan as a yogurt ingredient on the changes in pH, acidity, LAB number, and sensory quality of yogurt during storage at 4°C for 28 days was examined. Results: Pullulan did not affect yogurt pH, but the addition of 2.0 % w/v pullulan increased the acidity of yogurt as compared to that of the control yogurt. A statistically significantly higher total number of Lactobacillus, by approximately 1 logarithmic cycle, was found in yogurts with pullulan than in the control yogurt on the 28th day of storage. The yogurt with 1.0% w/v pullulan addition showed better sensory characteristics than that with 2.0% pullulan w/v addition. Conclusion: The conducted research proved that the presence of pullulan in the culture medium stimulates the growth of selected lactic acid bacteria and influences their fermentation capacity. The use of 1.0 % w/v pullulan during the production of yogurts allowed to obtain a sensorically acceptable product, it had a protective effect on the number of lactic acid bacteria during 28 days of refrigerated storage of yogurt.