Software simulator improves quality of microwave reheated frozen foods

Consumer habits have changed remarkably over the past decade, leading to a massive increase in the ready food market. The technology of reheating frozen food in microwave ovens has therefore come under increasing scrutiny. Uniform heat distribution within the oven and throughout the food itself is therefore an issue of major interest to convenience food producers, appliance manufacturers and food customers alike.

Many variables to control

Several elements affect how food is heated in a microwave oven – from the shape of the packaging to the performance of the oven itself. In particular, multi-component foods such as those that make up ready meals often heat unevenly; this may cause both sensorial and microbiological problems.

“We developed product simulation software to predict microwave heating uniformity,” explains Birgitta Waeppling-Raaholt, specialist in electromagnetics and microwave processing at the Swedish Institute for Food and Biotechnology (SIK), which led the project. “This makes it possible to design the make-up of the food product – geometry, placement of different food components, packaging and so on – much faster and reduces experimental work.”

The MICRODEFROST MODEL software sets out to model how food components are defrosted and heated by microwaves, and how the heat is transferred – including conduction through the different components. Other SIK-developed software then controls heat distribution to make it more uniform. SIK software was used to establish what the important parameters were, and then helped to optimise their values.

As a result of this EUREKA project, it is now possible for convenience food manufacturers to introduce new convenience products more quickly for both the frozen and chilled product sectors. It also provides an important tool to enable microwave manufacturers to optimise their oven designs.

Global first

The MICRODEFROSTMODEL project was started by SIK, which had carried out earlier work on chilled food reheating. It sought help from EUREKA to find funding and partners. “We had worked in similar projects with EUREKA before,” says Raaholt. “We find that EUREKA is very open-minded.”

The Swedish and Polish partners in the four-year MICRODEFROSTMODEL project brought together appliance manufacturers, frozen food producers, and electromagnetics and radioelectronics modelling and software experts to devise a highly effective product development tool that is a world first. The resulting product development tool is already being offered to food companies to strengthen the competitiveness of the European ready food industry by improving end quality and speeding time to market. Potential spin-offs for this project include controlled pasteurisation of potentially infected products through more uniform heat treatment.