Second Edition The first edition of PRACTICAL DEHYDRATION published in 1971, was written primarily for the practical dehydrator, rather than for the chemist or theorist, whose interest in the industry might be more abstract or purely scientific

beetroot, 125 additives and process chemicals, 52 blanch air lift dryers, 83 dicing, 126 air separation, 228 apples, 170 peeling, 126 dryers, 174 ratio, 126 preparation, 172 sizing and selection, 126 ratio, 174

Published by Woodhead Publishing Limited, Abington Hall, Abington, Cambridge CB1 6AH, England First published 1971, Food Trade Press Second edition 1998, Woodhead Publishing Ltd 1998, Maurice Greensmith The author has asserted his moral rights. Conditions of sale All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy

The food manufacturing industry, in general, has always been a highly competitive business but no branch of it is more so than dehydration. Profitability hinges on so many factors, some of which are outside the manufacturer's control. One of the main hazards in this context is that of climate. Total solids in raw materials are the key to a viable operation, and, if these are low, due to wet growing conditions, the plant throughput is going to be seriously reduced

In broad terms, the quality control staff, under the supervision of a qualified food chemist, should be responsible for the following: ()The evaluation of quality of all incoming raw material, supplementary ingredients used in processing, chemicals packaging material, cellulose and other film, paper and fibreboard containers, and certain consumable stores: (2)All routine laboratory tests on raw material, finished products, lye and blancher liquor, boiler and processing water;

The size grading of dehydrates is an important function, both in the interests of quality and presentation, and also for the purpose of obtaining the optimum return on products undersize, or less than the standard cut. With almost all cut vegetables and fruits, there will be off-cuts from the dicers or cutters, which can be effectively separated from the primary product by the use of effective sieving machines

The main plant requirements for soup blending are an adequate number of ingredient bins, with discharge valves and weighing control, a collecting bin on a monorail beneath the ingredient bins, and good blending and mixing equipment

The dehydration of meat and poultry in granule form for soup ingredients is dealt with in this chapter, as being of more practical importance than the drying of meat in larger cuts, such as slabs, dice, etc which can only be dehydrated by the AFD method. Outlets for the latter products are relatively limited in Europe, whereas there is market for soup-making- materials. Meat granules and powders can be air dried or freeze-vacuum dried

Tomato powder is much in demand by dehydrated soup manufacturers, and is now produced in many countries where tomatoes are an indigenous outdoor crop. The heavy cropping Italian plum tomato is ideal for drying down to powder, and this is grown in most areas with a 'Mediterranean- type' climate. Tomatoes have a very low solids content-not more than 6 percent- and dehydration must be preceded by evaporating the pulped

The United States is by far the largest producer of dried fruits, raisins and prunes being the most important tonnage-wise, with figs, apples, apricots, peaches and pears following in order of tonnage produced Other countries with a substantial export trade in dried fruits are Greece(producing 90 percent of the world's currant supply), Iran, Turkey, Portugal,raq, Algeria, Australia, Argentina, Egyptand South Africa. Ofthe above, the Middle East countries are particularly in the drying of figs and dates