| Abstract [eng] |
The aim of this project is to process acid whey into whey protein powder using membrane filtration technology and to apply it in the production of bakery products. Different whey powder was produced using different drying methods during the scientific research. Analysis of the physical-chemical properties of produced powder was carried out evaluating the amount of protein, moisture, minerals, lactic acid, lactose, fatty acids and pH value. Protein fractions were determined by reverse phase liquid chromatography, electrophoresis and particle size was measured in whey powder samples. Ultrafiltration was chosen as an alternative way to reduce lactic acid amount in acid whey, and its suitability for this purpose was assessed. In order to find out the feasibility of powder application, the following functional properties of whey protein have been investigated: protein solubility, least gelation concentration, foaming capacity, water and oil holding capacity, emulsion formation and emulsion stability. The analysis of bakery products was carried out to evaluate the effect of the acid and sweet whey powder additive on cakes, as well as attempting to replace egg protein with whey protein concentrate. It was found that the drying method did not have a significant effect on the physical-chemical properties of whey powder, except for the particle size. The particle size of the spray-dried powder was bigger than that of the lyophilized powder. The drying method affected the functional properties of whey protein powder - the solubility of the powder obtained from the spray dryer was lower than that obtained by lyophilization. The whey protein fractions and their concentrations were determined during the high performance liquid chromatography study. The whey protein fractions were also determined by electrophoresis without considering their concentrations. It was found that ultrafiltration is the appropriate process to reduce the amount of lactic acid in the acid whey. Best quality cakes were obtained with addition of largest amount of tested sweet whey and acid whey powder. Only a part of the egg protein can be changed with a mixture of whey protein concentrate and water. Unacceptable quality cakes were obtained when more than 40 % of egg protein was replaced. |
