In previous investigations it has been shown that thermofluiddynamical processes occur in food related substances at high hydrostatic pressure (HHP) treatment. In order to gain insight into these processes an in-situ measuring technique for visualizing temperature and velocity fields has been developed. Based on extensive test series the them al and fluiddynamical processes in water have been analyzed. After pressurizing water onto 230 MPa within 12 seconds temperature gradients of 0.1 K/mm are generated in the visible field of the optical cell. The present study comprises investigations on liquids of higher viscosity. Sucrose solution of 50% (weight percent) has been chosen as model fluid because the viscosity data are available up to 600 MPa. The results show that the temperature gradients are six times higher than those in water under the same test conditions. This in turn may cause heterogeneities of biochemical processes in foods. This correlation has been confirmed by numerical simulations of an enzyme inactivation process. In the present contribution visualized inhomogeneous temperature fields arising in sucrose solution are presented and compared to the thermofluiddynamical processes in water.
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