Insolubility and denaturation of whey proteins of skimmed camel milk as affected by spray drying operating parameters

Abstract

The effect of spray drying process parameters (i.e., inlet temperature, atomization pressure, and feed flow rate) on the denaturation of whey proteins of skimmed camel milk was studied using a face-centered central composite design. Spray drying of skimmed camel milk (i.e., total solids of 8.4% [w/w]) produced powders with a total solids content of 94–97% (w/w), protein 22–29% (w/w) and lactose 27–31% (w/w). The process was optimized using response surface methodology in combination with desirability function. A maximum recovery of 61% of the total solids was achieved while still maintaining denaturation of whey protein and insolubility index levels at their minimum possible value of 39% and 0.1 mL, respectively. The final moisture content of the powder at these conditions was 3.3% (w/w). This implies that, as denaturation was the primary mechanism by which camel milk lose its protective proteins, minimizing denaturation would make it possible to produce skimmed camel milk powders with good nutritional and therapeutic values. The morphology of spray-dried skimmed camel milk processed at 140°C showed greater spherical intact particles than their cow milk powder counterparts.