Effect of the Addition of Milk Protein Preparations on Selected Quality Parameters and Nutritional Characteristics of Kefir

The aim of this study was to evaluate the effect addition various milk protein powder preparations (MPC-80, WPC-70, sweet whey, non-demineralized or demineralized whey permeate, rennet casein, buttermilk) selected quality parameters and digestibility proteins in kefir. Kefir samples analyzed were prepared under laboratory conditions with three industrial bacterial starter cultures. They examined microbiologically (lactobacilli, lactococci, yeast) for pH, total content, hardness, adhesiveness, water-holding capacity (WHC), (using two vitro methods along determination content available lysine glycine). counts lactococci lactobacilli estimated at levels above 7 6 log(CFU/mL), respectively. Yeast not found kefir samples. pH value 4.4–5.2. WHC dependent on type culture added. Each preparation added increased amount glycine. However, when converted 1 g protein, changes glycine variable depended both used.