BISCUIT MANUFACTURE BISCUIT MANUFACT·URE fundamentals of in-line production by PETER R. WHITELEY DIP. F.E., F.lnst. B.B. Head of the Department of Baking. Rush Green Technical College. Rmriford. Essex APPLIED SCIENCE PUBLISHERS LTD LONDON APPLIED SCIENCE PUBLISHERS LTD RIPPLE ROAD, BARKING, ESSEX, ENGLAND ISBN: 0-444-20072-X LIBRARY OF CONGRESS CATALOG CARD NUMBER 70-122961 WITH 121 ILLUSTRATIONS AND 5 TABLES Cl 1971 ELSEVIER PUBLISHING COMPANY LTD All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publishers, Applied Science Publishers Ltd, Ripple Road, Barking, Essex, England Author's preface THE intention of this book is to provide a guide for potential management and supervisors and for those who wish to understand the fundamental principles of biscuit manufacture. It does not set out to be a learned treatise. The purpose of the book is to simplify and explain processes and materials so that the 'mystique'is replaced by logic. Once the mystique is removed the biscuit maker is one step closer to anticipating and solving problems. In attempting to cover this subject within one concise volume, it is difficult to avoid over-simplification or generalisation, and apologies must be offered in advance where these occur. To wallow in the fine details of specialisation is to defeat the object of the book, and less would be achieved if the issues were confused. The reader's attention is drawn to the interpretation of formulae (recipes). Raw materials, equipment, methods, processes, and conditions vary considerably; the formulae are intended as blue prints from which, with a knowledge of the materials and aims of the processes, and by trial and error, a biscuit can be produced bearing some semblance to the original. All formulae should be interpreted in conjunction with the 'Guide to using formulae' at the beginning of Chapter 12. As the biscuit industry advances towards complete automation, plant and equipment become more advanced and sophisticated. Training of a very high standard is necessary to use sophisticated machinery efficiently, and where skills of this exacting degree are not available, then the simpler, less advanced equip ment, should be used. It is with this in mind that processes have been dealt with in such a way that they can be carried out by hand or through varying degrees of mechanisation. Similarly, the legislation regarding foods becomes so involved and changes so frequently that it is impossible to review for inclusion in a book of this nature. It is essential to be aware that there is legislation pertaining v vi AUTHOR'S PREFACE to practically every aspect of biscuit making and marketing, and as the legislation differs from country to country, further confusion arises. All governments issue pamphlets about their laws, and the appropriate Ministry or information office (in the United Kingdom, Her Majesty's Stationery Office) or legation should be approached for the current regulations. Upminster, 1970 PETER R. WHITELEY Acknowledgements AN expression of thanks and gratitude is due to all those who helped with advice, information and photographs to make this book possible, including: Baker Perkins Ltd, Peterborough British Cellophane Ltd, Twickenham Co-operative Wholesale Society Ltd, Biscuit Factory, Harlow Walter Denis Contacts Co., Ltd, Blackpool Flour Milling and Baking Research Association, Chorleywood J. Alan Goddard Ltd (Hecrona), Croydon J. W. Greer Co., Ltd, Bromley Kek Ltd., Macclesfield A. M. Lock & Co. Ltd, Oldham Machinery Continental Packaging Ltd (Aucouturier), Rochester Morton Machine Co. Ltd, Wi shaw E. T. Oakes, Ltd, Macclesfield Radyne Ltd, Wokingham Rank Precision Industries Ltd, Brentford Rose Forgrove Ltd, Leeds SIG Wrapping Machines Ltd, Croydon Simon-Vicars Ltd, Newton-Ie-Willows .Spooner Food Machinery Engineering Co., Ltd, Ilkley My greatest appreciation is due to my wife, whose untiring efforts of encouragement and help spurred me on at all times. Upminster, 1970 PETER R. WHITELEY vii. Contents AUTHOR'S PREFACE v ACKNOWLEDGEMENTS vii LIST OF FIGURES IN THE TEXT xi LIST OF TABLES xii LI ST 0 F P L ATE S xiii PART I RAW MATERIALS 1 Flour and cereal products 1 2 Fats and oils 22 3 Sweetening agents 34 4 Aerating agents 42 5 Dairy products 50 6 Fruits and nuts 59 7 Setting materials 69 8 Chocolate and cocoa products 73 9 Flavouring materials 81 10 Colouring materials 94 PAR T II CLASSIFICATION AND METHODS 11 Classification of biscuit types and methods of production 103 PAR T III FORMULAE-QUALITY CONTROL AND DEVELOPMENT 12 Basic ingredient proportions of biscuit doughs 1 27 13 Basic ingredient proportions of wafers, marsh- mallows, creams, and fillings 148 ix x CONTENTS 14 Quality control 161 15 Re-use and disposal of unsatisfactory products 189 16 Development 193 PART IV PLANT AND EQUIPMENT 17 Raw materials storage and handling 201 18 Mixing room equipment 209 19 Machine room equipment 219 20 Ovens and baking 230 21 Wafers and second process equipment 241 22 Ancillary equipment and automation 250 23 Packaging of biscuits 258 PART V GENERAL CONSIDERATIONS 24 Factory layout and hygiene 269 BIBLIOGRAPHY 289 INDEX 290 List of figures in the text 1. Longitudinal section of a wheat grain 4 2. The pH scale 47 3. Sketch of a yeast cell 106 4. Yeast reproducing by budding 107 5. Colony of yeast cells 1 08 6. Diagram showing enzymic activity during fennentation 111 7. Structure of a farinogram 163 8a. Farinogram: Manitoba flour 163 8b. Farinogram: strong English flour 164 8e. Farinogram: soft English flour 164 9a. Extensogram: Manitoba flour 166 9b. Extensogram: strong English flour 167 ge. Extensogram: soft English flour 167 10. Typical alveograms: (a) Manitoba flour; (b) strong English flour; (c) soft English flour 168 11. Typical graphs ofe xtensom eter: (a) Manitoba flour; (b) strong English flour; (e) soft English flour 170 12. Line drawing of Simon-Vicars vertically integrated dough feeding, gauging and laminating unit 221 13. Examples of wire band patterns (Baker Perkins) 231 14. Air blast gas burners for direct fired oven (Baker Perkins) 235 15. Diagrams illustrating the principle of forced air convection baking used in a Spooner oven section 236 16. Line drawing of a Walden refrigerated air blast cooling tunnel 248 17. Diagrams illustrating how metals affect the electromagnetic field of an electronic metal detector 254 xi List of tables 1. Structural composition of wheat 3 2. Typical analyses of flour samples 9 3. Typical analyses of milk and milk products 53 4. Table converting ingredient percentages to pounds when based on flour weight of 280 Ib (i.e. one sack) and vice versa 128/129 5. Examples of texture meter readings obtained on retail samples of various types of biscuits 181 xii