Comparison of the viscosity of camel milk with model milk systems in relation to their atomization properties.

To correlate the viscosity of camel milk with its atomization properties, first, the viscosity profiles of camel milk are compared with model milk systems (reconstituted skimmed cow milk powder). Then, atomization experiment was conducted using model milk systems and finally, the findings of the atomization experiments were coincided with the viscosity profiles. The effect of total solids of whole (10% to 40%) and skimmed (7.5% to 30%) camel milks on its viscosity was investigated. At 30% total solids level and a temperature of 20 °C, skimmed camel milk exhibited a viscosity of 7.68 mPa.s whereas whole camel milk 8.96 mPa.s. This value is small compared to suspension of reconstituted skimmed cow milk powder, which reached up to 18.55 mPa.s and to that of suspension of whey protein concentrate (28.15 mPa.s). By raising the total solid from 20% to 30%, it was shown that, the average spray droplet size would be changed from 18.77 to 29.40 µm and the span from 1.76 to 1.55. Based on their viscosity profiles, these values would be obtained for camel milk at total solid values of 35% for whole and 38% for skimmed milks. This would allow camel milk to be concentrated to higher total solid levels than bovine milk. PRACTICAL APPLICATION: Converting camel milk into powder by spray drying will have a great role in its commercialization. To do so, establishing knowledge on the viscosity of camel milk at different total solids levels in relation to its atomization properties would be of paramount importance. Because, this would enable us to fine tune the viscosity of the milk to arrive at a quality powder with all the desired techno-functional properties. Moreover, it will also contribute by furnishing engineering data pertinent to the development, design, or choice of appropriate nozzles for atomization of the milk during spray drying at different drying set ups.