The objective of the research study was to obtain and determine the rheological properties of model fermented beverages produced from selected whey protein preparations with 7 % saccharose and inulin added in the amounts of 2, 3 and 4 %. As starter cultures were used two lactic acid bacteria capable of synthesizing exopolysaccharides. With the use of a Haake RS300 dynamic rheometer, flow curves were determined, and, upon the analysis thereof, there were computed a consistency index (K) and a flow behaviour index (n) of the samples studied. Along with the increasing concentration of whey powder (SP), whey with reduced lactose (SZZL), and whey protein concentrate (WPC 65), the value of the consistency index decreased, but it increased at higher concentration levels of whey protein concentrate (WPC 35) and whey protein isolate (WPI). Of all the samples analyzed, the products fermented on the basis of WPC 35 were characterized by the highest K value. The adding of saccharose and inulin caused the consistency of the beverages to improve. The flow behaviour index values were less than one for all the samples studied and this fact reflected their pseudo-plastic character. The lowest, similar values of consistency index were reported in the case of the samples made on the basis of whey powder (SP) and demineralised whey (SZ) with saccharose and inulin added at various concentration rates. However, the samples made on the basis of WP 3 with added sucrose and 4 % of inulin were characterized by the highest values of rheological properties. In the latter case, the consistency index values were 10.5 Pa·sn (MYE 95) and 10.2 Pa·sn (MYE 96).
fermented milk beverages, whey protein preparations, inulin, rheology