The Microwave Processing of Foods (Woodhead Publishing Series in Food Science, Technology and Nutrition)

With such advantages as more rapid heating and preservation of sensory and nutritional quality, microwave processing has proved a versatile technology. This important book reviews the wealth of recent research on how this technology affects particular foods and how it can be optimised for the food industry. Part one discusses current research on how microwaves interact with the dielectric properties of foods and reviews its effects on nutritional and sensory quality. Building on this foundation, the range of applications of microwave processing from baking and drying to blanching, thawing and tempering are reviewed. It also looks at packaging issues. The final part of the book covers the key area of process measurement and control to ensure more uniform heating of food products. With its distinguished editors and international team of contributors, The microwave processing of foods is a standard reference for all those wishing to maximise the benefits of this important technology. Reviews recent research on how microwave processing affects particular foods Discusses how this technology can be optimised for the food industry An assortment of examples are used to illustrate key points Contents......Page 6 Contributor contact details......Page 12 1.2 Definitions and regulatory framework......Page 18 1.3 Electromagnetic theory......Page 20 1.4 Microwave technology......Page 28 1.5 Summary......Page 34 1.7 Appendix: notation......Page 35 2.1 Introduction......Page 37 2.2 Dielectric properties of foods: general characteristics......Page 38 2.3 Factors influencing dielectric properties......Page 39 2.4 Dielectric properties of selected foods......Page 49 2.5 Sources of further information and future trends......Page 52 2.6 References......Page 53 3.1 Introduction......Page 56 3.2 Measurement techniques: closed structures......Page 57 3.3 Measurement techniques: open structures......Page 65 3.4 Further analysis of dielectric properties......Page 68 3.6 References......Page 72 3.7 Appendix: notation......Page 74 4.1 Introduction......Page 76 4.3 Microwave interactions with dielectric properties......Page 77 4.4 Measuring microwave heating......Page 79 4.5 Microwave heating variables......Page 81 4.6 Product formulation to optimize microwave heating......Page 83 4.8 References......Page 88 5.1 Introduction......Page 91 5.2 Microwave interactions with food components......Page 93 5.3 Drying and finishing fruits, vegetables and herbs......Page 94 5.4 Blanching and cooling fruits, vegetables and herbs......Page 96 5.5 Dough systems......Page 100 5.6 Meat......Page 105 5.7 Flavor and browning......Page 108 5.8 References......Page 109 6.1 Introduction......Page 120 6.2 Industrial microwave applicators......Page 121 6.3 Applications......Page 124 6.4 Future trends......Page 129 6.5 References......Page 130 7.2 Principles of microwave baking......Page 134 7.3 Technologies and equipment for microwave baking......Page 136 7.4 Strengths and weaknesses of microwave baking......Page 137 7.5 Interaction of microwaves with major baking ingredients......Page 139 7.6 Application of microwave baking to particular foods......Page 143 7.9 References......Page 151 8.1 Introduction......Page 157 8.2 Quality of microwave-dried food products......Page 162 8.3 Combining microwave drying with other dehydration methods......Page 163 8.4 Microwave drying applied in the food industry......Page 164 8.5 Modelling microwave drying......Page 165 8.6 References......Page 166 9.1 Introduction......Page 168 9.2 Blanching and enzyme inactivation......Page 169 9.3 Comparing traditional and microwave blanching......Page 172 9.4 Applications of microwave blanching to particular foods......Page 175 9.5 Strengths of microwave blanching......Page 180 9.6 Weaknesses of microwave blanching......Page 182 9.7 Future trends......Page 183 9.9 References......Page 185 10.1 Introduction......Page 189 10.2 Conventional thawing and tempering systems......Page 190 10.3 Electrical methods......Page 194 10.4 Modelling of microwave thawing......Page 201 10.5 Commercial systems......Page 202 10.6 Conclusions and possible future trends......Page 204 10.7 References......Page 205 11.1 Introduction......Page 207 11.2 Factors affecting temperature distribution in microwaved foods......Page 208 11.3 Passive containers......Page 209 11.4 Packaging materials......Page 215 11.5 Active containers......Page 222 11.6 Future trends......Page 230 11.7 References......Page 231 12.1 Introduction......Page 236 12.2 Factors affecting food heating: power output......Page 237 12.3 Factors affecting food heating: reheating performance......Page 240 12.4 Methodology for identifying cooking/reheating procedure......Page 249 12.5 Determining the heating performance characteristics of microwave ovens......Page 251 12.7 References......Page 256 13.1 Introduction......Page 258 13.2 Methods of measuring temperature distributions......Page 259 13.3 Physical principles of different temperature mapping methods......Page 261 13.4 Measurement in practice: MRI analysis of microwave-induced heating patterns......Page 273 13.5 Conclusions......Page 276 13.6 References......Page 277 14.2 General design issues for industrial microwave plants......Page 279 14.3 Process control systems......Page 291 14.4 Examples of process control systems in food processing......Page 299 14.7 References......Page 306 15.1 Introduction......Page 307 15.2 Heat distribution and uniformity in microwave processing......Page 308 15.3 Heating effects related to uniformity......Page 312 15.4 Examples of applications related to heating uniformity......Page 314 15.5 Modelling of microwave processes as a tool for improving heating uniformity......Page 316 15.6 Techniques for improving heating uniformity......Page 319 15.7 Applications to particular foods and processes......Page 321 15.8 Future trends......Page 325 15.9 Sources of further information and advice......Page 326 15.10 References......Page 327 16.1 Introduction......Page 332 16.2 Modelling techniques and capable software packages......Page 335 16.3 Example of simulated microwave heating......Page 338 16.4 Future trends......Page 343 16.5 References......Page 346 16.7 Annotation......Page 348 Index......Page 349 Annotation The impact of traditional thermal processing on the sensory quality of food has led to an interest in alternative technologies. Amongst these, microwave processing has proved one of the most successful and versatile. It is now widely used in processes such as thawing, dehydration and backing. Edited by two leading authorities in the field, and with a distinguished international team of contributors, this collection reviews both the theory and practice of microwave processing. It covers such key issues as improving modelling and process control to ensure uniform heating in optimising sensory and nutritional quality. CONTENTS Part 1 Principles: Introducing microwave processing of food: Principles and technologies; Dielectric properties of foods; Measuring the dielectric properties of foods; Microwave heating and the dielectric properties of foods; Microwave processing, Nutritional and sensory quality. Part 2 Applicatins: Microwave technology for food processing: an overview; Baking using microwave processing; Drying using microwave processing; Blanching using microwave processing; Thawing and tempering using microwave processing; Packaging for microwave foods. Part 3 Measurement and process control: Measuring the heating performance of microwave ovens; Measuring temperature distributions during microwave processing; Improving microwave process control; Maximising uniform head distribution in microwave heating