THE INFLUENCE OF STARTER CULTURE TYPE ON THE RHEOLOGICAL AND TEXTURAL CHARACTERISTICS OF FERMENTED MILK PRODUCTS

Abstract

This article presents the results of a comparative study of the influence of various starter cultures on the physicochemical and structural-mechanical properties of fermented milk raw materials. Samples prepared using a traditional yogurt starter, a probiotic culture, and a kombucha inoculum served as objects of analysis. It was found that the use of kombucha significantly increased the fermentation duration to 8.2 hours, which is almost twice as long as the probiotic and yogurt samples, which were 4.0 and 4.5 hours, respectively. Upon reaching the isoelectric point (pH 4.6), the most stable coagulum was formed using the yogurt starter: hardness was 204.01 g, and consistency was 5377.62 g s. The probiotic sample was characterized by the lowest hardness at 123.7 g. Rheological analysis confirmed the pseudoplastic flow nature of all studied systems. The maximum hysteresis loop area, indicating a high degree of thixotropic structural restoration, was recorded for traditional yogurt at 2201 Pa/s, while for the kombucha sample, this value was 1444 Pa/s. Experiments have shown that the main structural changes in all gel types are initiated in the pH range of 5.4-5.1. The obtained data demonstrate the fundamental potential of using kombucha as an alternative biological agent for creating the specific texture of fermented milk drinks.