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Journal of Microwave Power
and Electromagnetic Energy (JMPEE) |
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TITLE |
Continuous-Flow
Microwave Heating of |
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AUTHORS |
1995 30 3 141-148 |
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Abstract Microwave heating
characteristics of orange juice were evaluated under conditions suitable for continuous
continuous-flow heat-hold-cool pasteurization process. Orange juice was
pumped through a helical glass coil located inside a domestic microwave oven
and exit temperatures were determined as a function of flow rate and initial
temperature under full power (700W, 2450MHz) heating conditions. The average
residence time of the fluid was computed by dividing the volumetric capacity
of the helical tube inside the microwave oven by the volumetric flow rate
under the test condition. Fluid temperature rise from the tube inlet to the
outlet was found to be non-linear based on the steady state temperature
profile of the fluid along the tube length as measured experimentally using a
fiber optic temperature probe. The calculated
average residence times were converted to equivalent thermal times (or
effective heating times) at the exit temperature by numerically integrating
the thermal effect of the measured temperature profile from which the
inactivation rate of enzyme pectin methyl esterase (PME) was computed.
Results indicated that microwave heating was considerably more effective Key Words: Microwave, Temperature, Heating,
Inactivation, Pectin methyl esterase, Kinetics, Pasteurization. |
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