Effects of high pressure treatment of mix on ice cream manufacture

Effects of high pressure (HP) treatment on ice cream mix and ice cream prepared therefrom were studied. HP treatment had little effect on the size of the milk fat globules, but increased the viscosity of the ice cream mix considerably. The viscosity of HP-treated ice cream mix increased with increasing pressure and treatment time and with increasing fat, milk solids non-fat and sucrose content of the mix. Transmission electron micrographs showed the presence of a network of micellar fragments, arising from HP-induced disruption, in the HP-treated mix and ice cream prepared therefrom. Ice cream from HP-treated mix showed a higher resistance to melting than ice cream from untreated mix. The network of micellar fragments is believed to be responsible for the increased viscosity and reduced melting, and is hypothesized to occur as a result of calcium-induced aggregation of caseins on decompression.