Fermented milk with an increased protein content could be an attractive product for human nutrition. It is believed that there would be a noticeable increase in the demand for products with higher protein content including beverages. Such beverages can be beneficial when used in calories-reduced diets because the intake of energy from the protein seems to have a greater effect on the feeling of satiety than the intake of fat or carbohydrates. The objective of the research study was to determine the effect of concentrating milk to approx. 6 % of protein with a concentrate (WPC80) and whey protein isolate (WPI) on the physicochemical and sensory properties of Bifidobacterium animalis ssp. lactis Bb-12, and on its texture and growth during fermentation. The control sample was milk concentrated by skimmed milk powder (OMP). The milk was concentrated to a protein content of 6 % using OMP or WPC80, or WPI. After 10-hour fermentation (37 ºC, 10 hours) there were determined a significantly lower pH value and a higher total acidity and lactic acid content in milk with WPI and WPC80 added compared to the OMP milk. Concentrating milk by adding OMP resulted in a significant increase in hardness, adhesiveness and stickiness. The fermented milk samples containing an increased amount of protein (OMP, WPI, WPC80) met the minimum therapeutic criterion, i.e. they contained more than 6 log of Bifidobacterium animalis ssp. lactis Bb-12 in 1 g of the product. The best stimulator of the Bifidobacterium growth was the concentrate of whey proteins (WPC80). By increasing the protein content in fermented milk using WPI, WPC80, OMP it is possible to knowingly shape the taste profile. Concentrating milk with WPC80 resulted in a more intensive fermentation, a higher count of bacterial cells (10.52 log CFU·g-1) and in lactic acid content (0.78 g/l), and as a consequence this intensified the acidic taste and smell of fermentation and reduced the sensation of sweetness. The whey protein isolate (WPI) was found to be the most advantageous replacement for OMP owing to the sensory characteristics of fermented milk.
fermented milk with increased content of protein, WPI, WPC80, Bifidobacterium