Ultrasonic processing in yogurt production technology

The aim of the study was to study the effect of ultrasonic treatment on the rheological and total qualitative characteristics of finished products in the production of yoghurts. The raw materials used were normalized pasteurized milk with a fat content of 2,5 %, protein and skimmed milk residue — at least 3,2 and 9,5 %, respectively, Lactoferm ECO dry yogurt starter culture (Streptococcus salivarius subsp. thermophilus, Lactobacillus delbrueckii subsp. bulgarius). The results of the analysis of the dispersed composition of the milk mixture after 2,5 hours of fermentation, as well as the dependence of the shear stress and the effective viscosity coefficient on the deformation rate gradient are presented. Ultrasonic treatment helps to increase the dispersion of the milk mixture, the formation of a homogeneous mesh protein matrix with a high level of interconnections and a smaller pore size. A comprehensive study of rheological parameters, microscopy and organoleptic analysis allowed us to conclude that samples of fermented milk product produced using ultrasonic processing have higher consumer properties compared to yogurt obtained using traditional technology.