Professor Ronnie Magee
BSc (Queen’s University Belfast),1972
PhD (Queen’s University Belfast),1975
Emeritus Professor of Chemical Engineering
Tel: + 44 (0) 28 9097 4255
Fax: + 44 (0) 28 9097 6524
Baking is a complex process that brings about a series of biochemical, chemical and physical changes in the food material such as: gelatinisation of starch, denaturation of proteins, ration of carbon dioxide from leavening agents, volume expansion, evaporation of water, crust formation and browning reactions. Microwave baking offers advantages, compared to conventional methods, such as energy efficiency, faster and selective heating, improved nutritional quality, and chemical and physical effects promoted by heat generated by the microwaves.
The research questions we are addressing include:
Temperature and moisture loss profiles of a cake batter system can provide useful insights to the mechanism of heat and mass transfer during microwave baking, and be used to improve the quality of microwave baked products. Also, the dielectric properties of food materials and their constituents are key factors in understanding their interactions with microwaves. Therefore, the main objectives of the research are to:
Moisture removal from solids, to a level at which microbial spoilage is minimised and the product is relatively chemically stable, is an integral part of food processing. Therefore, drying is one of the important steps and common processes used to improve food stability for long-term preservation of final products. During the drying process, loss of water and increase in temperature cause stresses in the cellular structure of the food, leading to a change in shape and dimensions. The physiochemical changes that occur seem to affect the quality of the dehydrated product, with the method of drying, in particular, affecting the thermal degradation of important flavour and nutritional substances. Dehydrated products are usually rehydrated prior to their use. Rehydration is a complex process aimed at the restoration of the properties of the raw material. There is one main question related to this research.
Therefore, we are undertaking experiments to:
Due to their temperature sensitive nature, many pharmaceutical products are dried under vacuum to facilitate solvent evaporation at reduced temperatures. However, this necessitates long drying times and represents a processing bottleneck. Microwave heating of such materials at reduced pressures offers a more rapid method of moisture removal, without the risk of product damage. However, the dielectric and thermal properties of a complex pharmaceutical composition are rarely known, and moreover, they change during a drying process, which makes accurate mathematical modelling rather uncertain. The aims and objectives of this research are to build an understanding of, and to mathematically describe the Design Space for the microwave assisted drying of pharmaceutical active ingredients and powders.
Therefore, the research questions we are tackling are:
Therefore, we are constructing experiments to:
Encapsulation of Biopolymers and Synthetic Polymers
Encapsulation is an extensively used technique to capsulate food flavorants, cosmetics, drugs, protein, antigens, cells and enzymes. Microcapsules are produced by many methods and the most common include: extrusion; solvent evaporation; phase separation (coacervation); interfacial polymerisation; spray drying; and ionotropic gelation.
The specific objectives of the research include the following.