Fundamentals of Food Reaction Technology

Excerpt. © Reprinted by permission. All rights reserved. Fundamentals of Food Reaction TechnologyBy Mary Earle, Richard EarleThe Royal Society of ChemistryCopyright © 2003 Leatherhead International LimitedAll rights reserved.ISBN: 978-1-904007-53-1ContentsPREFACE, 1. IMPORTANT PROBLEMS IN FOOD PROCESSING, 1, 2. PRODUCT CHANGES DURING PROCESSING, 32, 3. PROCESSING OUTCOMES, 73, 4. ACHIEVING BETTER FOOD PRODUCTS, 109, 5. BROADENING THE NET, 144, INDEX, 182, CHAPTER 11. IMPORTANT PROBLEMS IN FOOD PROCESSING1.1 IntroductionFood processing includes all the activities that control the nature of food between the agricultural and marine production and its final eating by the consumers. It includes everything from the controlled conditions in the transport and storage of whole fresh meat, fish, fruit and vegetables, to the complex processing producing food ingredients followed by manufacturing to produce the final consumer product. Before being eaten, biological materials from agriculture or fishing are transformed through processing into the finished foods the consumer wants. Food processing makes the food products more attractive, more satisfying, safer and easier to eat, and preserves them from deterioration. It includes building up desirable constituents and removing or reducing undesirable ones, encouraging enzymes to develop desirable flavours and textures and removing or inhibiting enzymes causing undesirable changes, growing microorganisms to create flavour and texture and destroying them to prevent harm to the consumer or decay of the food.Food products are the outcomes of food processing, and it is important to identify the desirable product qualities and the undesirable and even unsafe product qualities. The products are the aim of food processing, and processing needs to be designed and controlled to give the product qualities identified and wanted by the consumers. Food processing is diverse, complex, and often carried out on a large industrial scale.1.2 Changes During Food ProcessingProcessing causes changes in the food materials; some of the changes are shown in Table 1.1.These changes can be measured, so their progress during processing can be followed and studied by the food technologist. The progress of processing can be measured in many ways, such as chemical analysis, physical measurements, counts of microorganisms, and colour, texture and flavour assessments by sensory panels. Changes can often be described in terms of the changing chemical composition, that is changes in the concentrations of the chemical components, but sometimes this is not possible and sensory, physical or microbiological measurements arc used to quantify the changes.Measurement reveals continuing change with time during the process. As our knowledge extends over ever-wider ranges of foods and food processing, and our analytical skills increase, the measured changes arc increasingly found to be systematic and describable in quantitative terms. The quantitative data from change measurement can be fitted to mathematical equations and to physical models. The models can be tested and, if necessary, modified until they fit observations adequately for practical processing purposes. Once the models are sufficiently established, they can be used to predict changes in processing between and sometimes beyond the original processing conditions. The models can be employed industrially to guide the processing, to control its extent, and to design new processes and equipment. They can predict outcomes under different processing conditions, conditions that can be set before the processing is started and regulated until completion. Important processing variables include temperature, time, moisture level, pH and atmosphere, and different levels can be set to give the processing conditions.The changes start when the process begins, and move on through the processing towards defined ends. The changes differ in their desirability between what are called custo