Ohmic Heating Behaviour and Rheological Properties of Ice Cream Mixes

Abstract

Ohmic heating is an alternative heating method for Maras-type ice cream mix, which is a traditional ice cream in Turkey. Fast and uniform heating is necessary for the pre-heating of ice cream mixes. Maras-type ice cream, produced in continuous system, was investigated in this study. The results obtained were compared with those of standard ice cream. The ice cream mix used for this study was supplied before the pasteurization step. A voltage gradient of 10–60 V/cm was used to heat the ice cream mixes ohmically from 4°C to 80°C. Temperature dependent electrical conductivity relations were obtained for different ohmic heating rates. Electrical conductivity of the standard type ice cream mix was lower than that of the Maras type ice cream mix. Fat content and temperature had an effect on the electrical conductivity values. The rheological properties of the ice cream mixes were also measured at 4, 25, 40, 60, 70, and 80°C by a Brookfield viscometer. Experimental data were evaluated according to power the law model—rheological constants (K, n) of Maras type ice cream mix were found to be greater than the standard type ice cream mix and increased with temperature.

Keywords:

• Ice cream
• Electrical conductivity
• Rheology
• Ohmic heating
• Voltage gradient

ACKNOWLEDGMENTS

The authors would like to thank Unilever-Turk S.A for support of raw materials to this project.

Notes

7. Icier, F. The experimental investigation and mathematical modelling of ohmic heating of foods. PhD diss., Ege University, The Institute of Natural and Applied Sciences, Izmir, Turkey. 2003.