Practical Dehydration Maurice Greensrnith 2nd edition WOODHEAD PUBLISHING LIMITED Cambridge England Published by Woodhead Publishing Limited, Abington Hall, Abington, Cambridge CB 1 6AH, England First published 197 1, Food Trade Press Second edition 1998, Woodhead Publishing Ltd 0 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, recording, or any information storage and retrieval system, without permission in writing from the publisher. While a great deal of care has been taken to provide accurate and current information, neither the author, nor the publisher, nor anyone else associated with this publication, shall be liable for any loss, damage or liability directly or indirectly caused, or alleged to be caused, by this book. British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library. ISBN 1 85573 394 3 Printed by St Edmundsbury Press, Suffolk, England. Acknowledgements The author would like to acknowledge his debt of gratitude to his many friends in the food industry who have supplied photographs to illustrate this second edition and information on recent new technology in plant and processing. Acknowledgement is also made to Niro Atomizer for the latest technology details on tomato and coffee drying. Also Mitchell Dryers Ltd, Carlisle, have given invaluable assistance in making available their pilot drying plant in the factory for experimental dehydration trials. Mr Glenn Watters of the Western Regional Research Centre of the USDA, Berkeley, California, together with Dr Otto Silberstein of Gilroy Foods Inc have generously supplied updated information on American onion drying technology. The author also thanks the Marchese Lupi di Saragno in Vigatto, Italy, for supplying details and photographs of effluent screening technology in high density stock breeding units for meat, ham and pig meat processing in the Parma, Bologna region, particularly in the context of Parma Hams. Much information has been collated on dehydration feasibility by the author from the many studies he has carried out in the course of 12 years in countries as diverse as Egypt, India, South America and Eastern Europe, promoting interest in onion dehydration; and in Kenya, South Africa, China, Macedonia, Greece, Turkey and in Western Europe where 3 vegetable dehydration in general has been taken up seriously. Poland has been involved with considerable tonnages of potato products in flake and granule form. There were, of course, instances where the infrastructure failed to meet up with the requisite parameters in horticultural terms, particularly in sub-tropical and tropical regions where irrigation and power plant were inescapably involved. Site photographs indicate where such infrastructural problems arose, notably in Northern Nigeria where attempts were made to irrigate many hectares of scrub/desert land on the southern shores of Lake Chad. Full cognisance was not taken of the lack of horticultural manpower available to take full advantage of the newly irrigated land where new skills were needed. A second example was in Pernambuco, Brazil, where the Rio Francisco offered massive reserves of irrigation water, excellent manpower training in horticulture, but not sufficient risk capital to put the irrigation and power plant in place, thereby enhancing the infrastructure to support food processing. Neither government nor private investors had the risk capital available at the time of the study. In central Turkey where cotton growing tended to be on a mono- culture basis, diversification into vegetable processing failed to attract conservative farmers and there was insufficient interest to wait for some three to four years before a return on equity profit could be anticipated. Very interesting information was gained through studies in Iran where desert irrigation is very feasible, thanks to the construction possibly a century or more ago of underground ducts extending from a mountain range on the shores of the Caspian Sea to regions as distant as Khoramshaar (central Iran) from where contour irrigation is carried out efficiently by Israeli management on annual crops of tomatoes. Desert horticulture has good potential if a political solution can be found in the future. In Israel this has been undoubtedly proved and the fact that, in the case in point, international co-operation can pay off handsomely if the will can be sustained. In some of the infrastructural studies the author acknowledges the patience and invaluable help offered by Mike Cannon, Technical Manager of Mitchell Dryers Ltd, for suggesting modifications on standard drying plant design where exceptional circumstances prevailed and standard plant did not meet requirements. The author also thanks the following for their permission to use illustrative material - Dodman Ltd, Peter Holland Ltd, International Machinery Corp, Mitchell Dryers Ltd, Niro Atomizer Ltd, Nymek, Rosin Engineering Co Ltd, Rossi & Catelli, Russell Finex Ltd, Tito Manzini, Urschel Laboratories Inc, Zacmi. 4