Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 8, 2003
Publication Date: March 16, 2004
Citation: Onwulata, C.I., Konstance, R.K., Tomasula, P.M. 2004. Minimizing variations in functionality of whey protein concentrates from different sources. J. Dairy Sci. 87:749-756. Interpretive Summary: Previous attempts to use whey protein concentrates (WPC) to fortify extruded products made from corn meal have not been successful. The added WPC prevents puffing of the corn meal snack when it is extruded. It was discovered that some of the WPC products used in experiments affected the quality of the finished corn meal snacks more than others and if there were large differences in the particle sizes of the WPC and corn meal fed to the extruder. WPC is made by concentrating whey, a byproduct of the cheesemaking process, and then drying it. Drying affects the particle-sizes of the finished dried product. Manufacturers use different drying conditions. In these experiments, six different WPC products were purchased from five companies. These WPC products were sieved to separate larger particles from the smaller ones. Functional properties of the WPC products were determined and compared to those of the sieved products with more consistent particle size. The results indicate that variations in functional properties were minimized by matching particle sizes. The ability to maintain uniform functional properties will allow for the development of more nutritious extruded puffed products.
Technical Abstract: Improvements in processing technology have enhanced the nutritional and functional properties of whey protein concentrates (WPC) leading to their increased use in different food products. However, the extent of heat treatment, especially that received during the drying step, affects the quality of the WPC and wide variation in product quality exists from manufacturer to manufacturer. This limits their use as a fortifying agent. In this study, six commercial WPC with 80% protein content (WPC80) were examined to determine their particle size distribution and density and functional properties such as solubility, gel strength, foam volume and stability. Significant (p<0.05) differences were observed among all products for every property compared. Particle size was the most important determinant of functional characteristics. WPC80 with large particle size had significantly (p<0.05) greater fat content and was less soluble with poor foam stability; but narrowing the particle size distribution through sieving, minimized variations in functional properties. Sieving all products within the particle size distribution range of l00 to l50 microns minimized variation in physical composition, making functionality uniform.