Maillard reaction products formation and antioxidative power of spray dried camel milk powders increases with the inlet temperature of drying

Demand for camel milk (CM) is increasing worldwide, due to its high nutritious value and health benefits. In this study, whole CM powders were produced by spray drying (SD) at six inlet temperatures (190 degrees C-250 degrees C) and by freeze drying (FD). Physicochemical and functional properties of CM powder proteins were investigated. SD at higher inlet temperatures (230 degrees C-250 degrees C) resulted in higher extent of Maillard reaction (MR), in comparison to lower temperatures (190 degrees C-200 degrees C) and FD treatment. Both treatments had negative effect on casein solubility, while whey proteins remained soluble and slightly increased its solubility with the extent of MR. The CM powders obtained at higher inlet temperatures demonstrated improved antioxidant activity. Secondary structure of whey proteins did not differ among the samples, while surface hydrophobicity of whey proteins was higher in all SD than in FD samples, suggesting only limited denaturation of camel whey proteins at higher inlet temperatures of drying. Thus, the effects of SD under the conditions applied in our study did not decrease camel whey protein solubility, while drying procedure itself regardless of temperature decreased solubility of camel milk caseins. MR generated during CM processing could be an important means of compensating for the lack of antioxidant protection normally associated with beta-lactoglobulin but happens to be absent from this milk.