Effect of enzymatic cross-linking on casein micelles thin film structure

Milk and milk components are mainly used for related food products. Nevertheless, some of the milk constituents such as casein have alternative non-food applications. In ancient Egypt caseinbased glue was first used. Milk casein proteins are also used for other technical applications [1] including plastic manufacturing [2], fiber textile [3], methane gas production [4]. Casein proteins in bovine milk include four main types: α1s-casein (38 %), α2s-casein (10%), β-casein (36 %) and κcasein (13%), that are involved in formation of hydrated casein micelles of sizes on the order of 150-300 nm [5]. Various models [6] are proposed for casein micelle structure including coat-core, sub-micelles, and the internal structure. The coat-core model describes the micelle as an aggregate of casein proteins with inner layer composition different from the outer layer. The sub-micelles model proposed the micelle as roughly spherically uniform sub-micelles which are linked together via a calcium phosphate ion cluster. The internal structure model specifies the mode of aggregation of different caseins.