Enzymatic hydrolysis and extensive heat treatment induce distinct modifications of cow's and camel milk proteins of relevance for production of infant formula
Natalia Zofia Maryniak, Ana I. Sancho, Søren Drud-Heydary Nielsen, Lotte Bach Larsen, Yumei Gao, Katrine Lindholm Bøgh, Egon Bech Hansen
Abstract
Camel milk is an alternative to cow's milk as protein source for infant formula. Reduced allergenicity is usually obtained through enzymatic hydrolysis of milk proteins. Heat treatment is another route to modify allergenicity. This study investigated the effect of enzyme hydrolysis and extensive heat treatment on the size, aggregation mechanisms, and modifications of camel milk proteins in comparison to the effect on cow's milk proteins. Disulphide bonds stabilized casein micelles in cow's milk but not in camel milk. The formation of large stable complexes by extensive heat treatment was prominent in cow's milk and not in camel milk. In both milks heat treatment led to equal levels of Maillard reaction, whereas sugar independent cross-linking was less pronounced in camel milk. Low sequence identity, different relative composition, and complete absence of β-lactoglobulin in camel milk are likely explanations for the different properties of cow's and camel milk. Production of infant formula based on camel milk should accordingly employ process parameters specifically adapted to this type of milk.