Foreword

The overall goal of the food processing industry is to convert raw materials into high valued finished products at the lowest cost. Due to significant variations in raw material properties, the main challenge of the food process engineer is to produce a final product of consistent quality. It is extremely important that the process engineer be aware of the latest scientific advances that would allow for the production of the highest quality products. This book, "Food Processing: Recent Developments" edited by Anilkumar Gaonkar masterfully brings together the most recent concepts in thermal conversions, food component separation and food process sensing and control.

Accurate and rapid methods to measure food product characteristics are crucial for both industrial and research applications. Many new process sensor and control systems are being developed to characterize everything from raw ingredients through to the packaged product. Nuclear Magnetic Resonance (NMR), ultrasonics, and X-rays diffraction have great potential for the sensing and control of food processes. NMR has emerged from the medical field to have eventual widespread use in the food industry. Not only can NMR be used to measure the rates of crystallization, freezing, and diffusion processes but also to monitor flow profiles during heating, cooling and extrusion processes. Currently, NMR is used for experimental applications but in the near future NMR will emerge as a rapid, versatile, and non destructive technique for a wide range of on-line process and quality control applications. Ultrasonic techniques also have enormous potential for use as foreign body detection, temperature, flow, and composition measurements. X-ray techniques have been successfully used to measure rapid and long term physical and chemical changes in foods. Although current equipment is expensive and further research is necessary, major advances are being made that will make on-line sensing and control of a wide range of products and processes possible in the near future.

Selecting the correct separation process is an important part of developing optimal food processes and products. Selective removal of food components can be used to develop higher valued products, at minimal loss during processing. Chromatography, extraction and membrane processes provide some of the most innovative and cost effective methods for separating and concentrating food and biological components. Membrane processes provide gentle separation at low temparature in both aqueous and non-aqueous and in reactive and non reactive situations. Future applications can include altering composition and also microbial removal. Chromatographic methods are important for selective removed and purification of enzymes and other biological material. Extraction and reverse micell methods are also excellent techniques to remove active constituents and also to remove undesirable constituents. Future advances are expected in the use of aqueous two-phase extraction methods. Major advances are needed in separation systems to lower the final process cost, to develop methods for scaling up to high volume operations and to facilitate complex highly variable raw materials.

Thermal processing methods are the main stay of food preservation. The use of high pressure, radiation, freezing, extrusion and aseptic methods lead to products of unique properties. High pressure is a promising method that has the main advantage of inactivating enzymes and microorganism without the destruction of nutrients and without changing flavor and taste. Bacterial spores can also be killed at high pressures when the product temperature is elevated to 60°C. Aseptic processing through the use of food has advanced from liquids only to particulates through the use of electrical heating methods and through the use of new advances in pump and tubular heat exchange design. Ionizing radiation can be successfully applied to a number of foods without negative effects. However, widespread acceptance has been curtailed by the general public's reluctance to accept the use of "nuclear energy" for human consumption. Freezing of foods has also been successfully used to preserve foods for decades. However, the new freezing technologies will be based on increasing process efficiency and minimizing environmental concerns. Extrusion is the one of the most widely used techniques to change the form and texture of solid foods. By combining heat and pressure to transform raw materials into endless variety of products. Although the thermal methods can be used by themselves to preserve foods, several of the methods are more successful when used in combination. By the same token, not all methods of preservation are applicable to all foods. Therefore, careful study of all methods is necessary.

The complexity of foods demand a wide variety of processing methods to produce products of high quality. The food process engineer must understand and continue to be aware of the latest advances in processing techniques. This book provides an excellent source of information to help maintain the competitive advantage.

Martin R. Okos Professor of Biochemical and Food Process Engineering Purdue University West Lafayette, IN 47907

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