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Industrial Drying of Foods

Christopher G.J. Baker (Autor)

Buch | Hardcover

309 Seiten

1997 | 1997 ed.
Chapman and Hall (Verlag)
978-0-7514-0384-8 (ISBN)

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Drying is traditionally defined as that unit operation which converts a liquid, solid or semi-solid feed material into a solid product of significantly lower moisture content. In most, although not all, cases it involves the application of thermal energy, which causes water to evaporate into the vapour phase. In practice, this definition encompasses a number of technologies which differ markedly in, for example, the manner in which energy is supplied to the foodstuff and in which product is transported through the dryer. Depending on the dryer type, the residence time may vary from a few seconds to several hours. Dryers designed to handle liquid feedstocks are naturally quite different from those intended to process moist solids. Even within these two broad categories, however, many distinct varieties of dryer have evolved to meet specific process ing needs. The dryer is frequently the last processing stage in the manufacture of a dehydrated food product. As such, it may not only bring about the desired reduction in moisture content but may also have a significant effect on a number of other properties, such as flavour, colour, texture, viability, and nutrient retention, for example. These properties, which are generally considered to affect the perceived quality of the end product, are often influenced by the temperature- moisture content-time profiles experienced by the foodstuff as it moves through the dryer. The underlying chemistry and physics are highly complex and, broadly speaking, only poorly understood.

1 The industrial drying of foods: an overview.- 2 Drying fundamentals.- 2.1 Introduction.- 2.2 Basic dryer types.- 2.3 Thermodynamic properties of air-water mixtures and moist solids.- 2.4 Drying kinetics.- 2.5 Food quality parameters.- 2.6 Summary.- Acknowledgements.- References.- 3 Through-flow dryers for agricultural crops.- 3.1 Introduction.- 3.2 On-farm dryers.- 3.3 Commercial dryers.- 3.4 Dryer control.- 3.5 Design of through-circulation dryers.- 3.6 Crop quality and drying.- 3.7 Crop drying costs.- 3.8 Summary.- References.- 4 Fluidized bed dryers.- 4.1 Introduction.- 4.2 Basics of fluidization.- 4.3 Features of construction.- 4.4 Types of fluidized bed dryer.- 4.5 Operating considerations.- 4.6 Applications.- 4.7 Test procedures.- 4.8 Design methods.- Acknowledgements.- References.- 5 Spray dryers.- 5.1 Introduction.- 5.2 Spray drying principles.- 5.3 Spray dryer layouts.- 5.4 Meeting powder specifications.- 5.5 Special design features for hygiene and safety.- 6 Contact dryers.- 6.1 Introduction.- 6.2 Industrial equipment and applications.- 6.3 Theoretical overview of contact drying.- 6.4 Design of contact dryers.- Acknowledgements.- References.- 7 Freeze dryers.- 7.1 Introduction.- 7.2 Process overview.- 7.3 Description of the freeze drying process.- 7.4 Equipment.- 7.5 The cost of freeze drying.- 7.6 Freeze drying procedures.- 7.7 The packaging of freeze dried food.- 7.8 Conclusion.- References.- 8 Dielectric dryers.- 8.1 Introduction.- 8.2 The fundamentals of dielectric heating.- 8.3 Dielectric drying.- 8.4 Applications of dielectric heat in drying.- 8.5 Cost of RF and microwave dryers.- 8.6 Conclusions.- References.- 9 Specialized drying systems.- 9.1 Introduction.- 9.2 Pneumatic-conveying dryers.- 9.3 Spin-flash dryer.- 9.4 Rotary dryers.- 9.5 Tray and tunnel dryers.- 9.6 Band dryers.- References.- 10 Solar dryers.- 10.1 Introduction.- 10.2 Construction of solar dryers.- 10.3 Solar natural dryers.- 10.4 Semi-artificial solar dryers.- 10.5 Solar-assisted dryers.- 10.6 Economic evaluation of solar dryers.- 10.7 Design of solar dryers.- 10.8 Dryer operation and process control strategies.- References.- 11 Dryer selection.- 11.1 Introduction.- 11.2 Specification of the drying process.- 11.3 Preliminary dryer selection.- 11.4 Bench-scale tests.- 11.5 Economic comparison of alternatives.- 11.6 Pilot-plant trials and final selection.- 11.7 Typical examples of the use of the dryer selection algorithm.- 11.8 Summary.- References.- 12 Dryer operation and control.- 12.1 Introduction.- 12.2 Dryer operation.- 12.3 Safety, health and the environment.- 12.4 Dryer control and instrumentation.- References.

Zusatzinfo	XXII, 309 p.
Verlagsort	London
Sprache	englisch
Maße	156 x 234 mm
Themenwelt	Technik ► Lebensmitteltechnologie
ISBN-10	0-7514-0384-9 / 0751403849
ISBN-13	978-0-7514-0384-8 / 9780751403848
Zustand	Neuware