We have established the technological characteristics for the wheat dietary fiber Vitacel, extruded wheat flour and rosehip meal, specifically the capability to absorb humidity and fat, as well as to swell. The highest value for fat-absorbing capability was determined for the dietary fiber Vitacel at the level of (59.0±0.5 %). The optimal parameters for swelling plant-based ingredients were defined: temperature is (40±2) °C, duration is 30…40 min. The method of IR spectroscopy was applied to identify and compare the forms that bind moisture in the mixtures of dietary fiber with water and buttermilk. It was established that the transmission spectra of infrared rays for examined samples are similar in character. This indicates the formation of H-bound water poly-associates with the hydrophilic functional groups of the dispersed system, which promote the hydration and swelling of carbohydrates of food fibers. Based on the indicators for thermal stability and the outflow of liquid fat we have found the rational amount of dietary fiber in mixtures with a maximally possible (up to 25 %) replacement of butter with rosehip oil. For the samples containing Vitacel in the amount of 0.3 %, as well as 2.0 % of rosehip meal, the degree of outflow of fat was registered at the level of 19.1 %. A rather low value for this indicator is the result of interaction between the dietary fiber of varying degrees of treatment and the water and fat phases of milk mixtures. Replacing a part of milk fat with oils in the manufacture of products with the modified fat composition changes the consistency and reduces stability in the process of butter-formation and dispersion of moisture in a finished product. The addition of dietary fibers that act as technological ingredients ensures the required consistency of mixtures with the modified fat composition.