Staff
- Academic Staff
- Dr M.N. Ahmad
- Professor S.J. Allen
- Professor S.E.J. Bell
- Professor D.R. Boyd
- Professor R. Burch OBE
- Dr M.J. Cook
- Professor A.P. de Silva
- Dr A.P. Doherty
- Dr N.C. Fletcher
- Dr A. Goguet
- Dr W. P.D.Goldring
- Professor K.J. Hale
- Professor C. Hardacre
- Dr J.D. Holbrey
- Professor P. Hu
- Dr M. Huang
- Dr. J. Jacquemin
- Professor S.L. James
- Dr M.C. Lagunas
- Dr I.C. Lane
- Dr W.F. Lin
- Professor T.R.A. Magee
- Dr P. Manesiotis
- Dr C. Mangwandi
- Professor J. Mann
- Dr H.G. Manyar
- Dr A.C. Marr
- Dr P.C. Marr
- Professor J.J. McGarvey
- Professor A. Mills
- Dr M.J. Muldoon
- Dr P. Nockemann
- Professor E.V. Rebrov
- Professor D.W. Rooney
- Professor K.R. Seddon
- Dr G.N. Sheldrake
- Dr P.J. Stevenson
- Dr K. Tchabanenko
- Dr J. Thompson
- Dr J.S. Vyle
- Professor G.M. Walker
- Dr P.J. Walsh
- All Staff
Professor Ronnie Magee
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
E-mail: r.magee@qub.ac.uk
Research Keywords
Convective and microwave baking/dryingFlour confectionary
Starch materials
Pharmaceutical powders
Encapsulation
Research
Research is mainly centred on four areas:
- Convective and microwave baking of flour confectionary
- Drying and rehydration of starch materials
- Microwave drying of pharmaceutical powders
- Encapsulation of biopolymers and synthetic polymers.
Convective and microwave baking of flour confectionary
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:
- How are the physiochemical mechanisms of microwave baking fundamentally different from that of conventional baking?
- How do microwaves interact with the constituents in the dough?
- How can we improve the quality of microwave-baked products?
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:
- examine the heat and mass transfer (drying kinetics, surface and internal temperatures) of Madeira cake and oatmeal biscuit during baking;
- determine the dielectric and thermal properties of dough and its constituents, developing a predictive mode;
- measure baked-product quality and compare with conventionally baked cakes.
Drying and Rehydration of Starch Materials
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.
- Can we develop an effective and efficient rehydration technique for starch foods, which can be adopted by the food industry, to make products that are acceptable from a quality (organoleptic) and safety (microbiological) perspective?
Therefore, we are undertaking experiments to:
- determine the effects of various parameters on the moisture uptake and internal temperature of selected starch food systems, where the parameters will include material type (potato, pasta, rice), temperature, time, sample shape and drying technique;
- evaluate the quality of the rehydrated product as a function of rehydration time and moisture content;
- determine the effect of various parameters on microbial (Clostridium botulinum) inactivation.
Microwave Drying of Pharmaceutical Powders
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:
- Can we establish a relationship between drying conditions and the optimum performance of the process so that the Design Space developed in the bench scale system can allow industrial microwave assisted drying to be used in a rational rather than empirical manner?
- Can we construct a mathematical model which, for the first time, accurately describes the microwave assisted drying of pharmaceutical materials?
Therefore, we are constructing experiments to:
- Construct a confocal, in situ Raman spectroscopy system for 3-dimensional mapping of the composition of the formulation in microwave assisted dryers;
- Modify the agglomeration regime map model to predict optimal agitation in industrial pharmaceutical dryers;
- Comparatively assess the pharmaceutical performance of drugs processed in the microwave dryer including stability testing and other solid state properties required for formulation.
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.
- Investigate various encapsulation processes for specific purposes.
- Identify suitable materials for making microcapsules.
- Develop laboratory and pilot plant facilities for the manufacture of microcapsules.
