Domestic microwave ovens are now being used increasingly to heat and prepare foods as a fast alternative to conventional radiation and/or convection ovens. However, several problems have been identified, including the existence of hot and cold spots, and excessive heating at product edges and corners. This is important both from the food safety and the food quality of view. Also food preparations such as roasting (intended to give a crust) cannot be done in a microwave-only oven.
Appliances combining the microwave heating mode with a conventional heating mode such as forced air or grilling are increasingly popular in Europe. These microwave combination ovens are intended to overcome some of the problems with microwave-only ovens, while maintaining the advantage of speed over conventional ovens. However, the combined effect of these heating modes complicates the instructions for and operation of the appliances.
During the past decades several model-based procedures have appeared in thermal processing technology which are aimed at optimising the quality of foods while assuring the mandatory microbiological requirements. It has been shown that a considerable improvement of the process in terms of decreasing the process time and increasing the surface quality of the treated food can be achieved for the case of thermally sterilised conduction heated foods. It can be readily expected that the application of appropriate optimisation and control methods would improve multimode heating processes-significantly. However, the complexity of the governing models have hampered the application of optimisation methods to this process so far.
The overall objective of the proposal is to improve the operation of domestic ovens with multimode heating functions in order to optimise the final food temperature uniformity while minimising quality losses due to overheating and maintaining microbiological safety.
The following sub-objectives can be distinguished :
- to develop models and numerical software to predict the temperature in foods
during multimode heat transfer processes in microwave combination appliances;
- to develop numerical procedures to assess the uncertainty of the temperature
distribution inside the heated food as a consequence of the variability of product
and process parameters;
- to optimize the heating process as quantified by a series of performance
indicators, while safeguarding microbial safety;
- to develop robust online control procedures that would assure optimal
processing in spite of process deviations and product variability;
- to validate the developed procedures using model and real food systems in
existing household microwave combination ovens.
Funding SchemeCSC - Cost-sharing contracts
402 29 Göteborg
601 17 Norrköping