Electromagnetic Heating Processes.

The Food Refrigeration and Process Engineering Research Centre, tel:[phone], is currently involved in a three-year EU-funded project to develop processes that are use electromagnetic heating techniques to produce products with extended shelf-life and added value.

Preliminary investigations have shown that cereals, seeds and some vegetables can be improved in quality when subjected to electromagnetic fields, either after harvest or prior to freezing/storage.

MW processing activities have concentrated on enzyme inactivation of wheat and drying of yellow peas. With wheat, the aim has been to improve the baking quality of wheat flour by inactivating the heat-resistant -amylase without damaging the heat-sensitive gluten-forming protein. Parameters which influence the heat-resistance of gluten and - amylase are the specific MW and the initial moisture content of the wheat. Process design data have now been provided to optimize on an MW treatment.

With yellow peas, the aim is to improve the nutritional quality of germinated peas by using MW in combination with conventional heating processes. Results have shown that the combined effect of germination, followed by conventional drying and MW, improves the nutritional value of carbohydrates in peas.

RF processing activities have concentrated of the enzyme inactivation of soybeans and mustard seeds. RF treatment resulted in a reduction of 16 to 23% of trypsin inhibitor activity in soybeans. This reduction of trypsin inhibitor activity depends on the final temperature of the heat treatment and the premoisturization of the raw material. In mustard seeds, there were no significant differences in amino acid content and composition, and in fatty acid content and composition of raw and heat-treated seeds.