Properties and Fractal Analysis of High-Protein Milk Powders

Abstract

(1) Background: Optimization of production and evaluation of the quality of preparations containing milk proteins facilitates their use in various branches of the food industry. The aim of this study was to produce and characterize high-protein milk powders (MCC, SPC) obtained by membrane techniques, and to compare them with industrially produced powders (WPC, CH, WPH, WPI). (2) Methods: The composition, reconstitution and flow properties, particle size, and microstructure of milk powders were determined, and fractal analysis was performed. (3) Results: MCC and SPC produced by the membrane separation of skim milk and industrially produced powders were characterized by a wettability of >180 s and a high solubility (0.10–0.85 cm3), excluding MCC (10.75 cm3 of insoluble particles). Flowability expressed as the Carr index was very good in CH (<15%), good in MCC (15–20%), and fairly good in the remaining powders (20–25%). All powders were moderately cohesive, excluding CH, which was characterized by low cohesiveness. The analyzed preparations differed in the values of fractal dimension. (4) Conclusions: The reconstitution and rheological properties of high-protein milk powders were affected by their composition, particle size, porosity, and surface properties. The fractal approach to the microstructure of milk particles enabled the unambiguous detection of subtle differences in the microstructure of the analyzed samples, which could not be identified during a visual assessment.

Keywords

• membrane filtration
• micellar casein concentrate
• serum protein concentrate
• commercial high-protein milk powders
• reconstitution properties
• flowability