Effects of the demineralisation degree on physicochemical, functional, microstructural and powder flow properties of whey powder

This study aimed to investigate the effects of the demineralisation process on powder flow, physicochemical, functional, and microstructural properties of whey powders (WP). WP samples were produced from 50, 70 and 90% demineralised sweet whey concentrates. Although the salt, ash, and lactic acid content of the powders decreased with increasing demineralisation, pH increased. D [3,2] (surface area mean diameter) value of WP samples ranged from 28.2 to 60.9 μm, in which demineralisation increased the particle size. The colour values showed increased darkness and yellowness, attributed to the higher demineralisation process. Demineralisation improved solubility and foaming characteristics, whereas it decreased the wettability and dispersibility of samples. The caking and cohesion characteristics of WP were significantly decreased by demineralisation. Demineralisation significantly improved the powder flow characteristics of samples. The cohesion index decreased depending on the demineralisation degree increased. Also, demineralisation decreased the cake strength and compaction coefficient of samples. Mineral content decreased with increasing demineralisation, with some minerals showing more sensitivity to demineralisation than others. Scanning Electron Microscope images showed reduced caking and clustering in samples with higher degrees of demineralisation. The results highlighted the importance of demineralisation as an effective parameter to control the properties of WP. In conclusion, this study demonstrated that the degree of demineralisation had a substantial impact on the physical and functional properties of WP.