Influence of the composition of milk-protein κ/ι-hybrid-carrageenan gels on product properties

κ/ι-Hybrid-types of carrageenan are often used for stabilisation of milk-based systems. However, real food systems vary in their composition, so it is of interest to investigate the influence of the product composition on the gel properties and storage stability. A response surface experimental design with four factors was analysed: casein:whey-protein ratio, concentration of carrageenan, KCl and CaCl₂ addition to the milk system. The characteristics of the gels were determined by oscillatory rheometry. In the statistical fitted model using all ingredients as parameters it was shown that the storage modulus G′ was linearly dependent on the minor ingredients KCl and CaCl₂. Non-linearity was seen for the influence of the concentration of carrageenan. As the total protein content was kept constant at 5%, the linear increase of G′ with higher casein amount can be explained by the known interactions between casein and carrageenan.