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RSC Paperbacks THE SCIENCE OF SUGAR CONFECTIONERY W. EDWARDS Bardfield Consultants, Essex, UK ROYAL SOCIETY OF CHEMISTRY ISBN 0-85404-593-7 A catalogue record for this book is available from the British Library 0The Royal Society of Chemistry 2000 All rights reserved. Apart f r o m any fair dealing for the purpose of research or private study, or criticism or review as permitted under the terms of the U K Copyright, Designs and Patents Act, 1988, this publication may not be reproduced, stored or transmitted, in any f o r m or by any means, without the prior permission in writing of The Royal Society ofchemistry, or in the case of reprographic reproduction only in accordance with the terms of the licenses issued by the Copyright Licensing Agency in the U K , or in accordance with the terms of the licences issued by the appropriate Reproduction Rights Organization outside the UK. Enquiries concerning reproduction outside the terms stated here should be sent to The Royal Society of Chemistry at the address printed on this page.
Published by The Royal Society of Chemistry, Thomas Graham House, Science Park, Milton Road, Cambridge CB4 OWF, UK For further information see our web site at www.org Typeset by Paston Prepress Ltd, Beccles, Suffolk Printed by Athenaeum Press Ltd, Gateshead, Tyne and Wear, UK Preface While most people have eaten sugar confectionery at some time few people know the underlying science. Almost all sugar confectionery was developed not from an understanding of the science but by confectioners working by trial and error. In many cases this empirical knowledge was obtained before any scientific understanding was available. There is one exception to this rule and that is where products have been made to resemble sugar confectionery but are free of sugars.
This small area has absorbed more scientific effort than the rest of sugar confectionery put together. This book is intended for everyone who has eaten sugar confectionery and wondered what the science behind it is. The work is not intended as a manual of methods for making confectionery but does give illustrative examples of manufacturing methods. Some simple recipes have been included to allow readers to do some small scale confectionery making.
Experiments can be based on these recipes to study a number of areas relating to confectionery making. This book has to be dedicated to the largely anonymous confectioners who invented most sugar confectionery products. It is also dedicated to my old friend Brian Jackson. V Contents Chapter I Introduction 1 Food Law 2 The Scope of Sugar Confectionery 3 Health and Safety 3 Chapter 2 Basic Science 5 Stability 5 Colligative Properties 6 PH 7 Polarimetry 8 The Maillard Reaction 9 Densimetry 13 Refractive Index 14 Analytical Chemistry 14 Water Content 14 Sugar Analysis 16 Emulsions 18 The Chemistry of Oils and Fats 19 References 22 Chapter 3 Ingredients 23 Sugars 23 Dairy Ingredients 28 Vegetable Fats 33 Gums and Gelling Agents or Hydrocolloids 35 Chewing Gum Ingredients 58 vi i viii Contenis Chapter 4 Emulsifiers, Colours and Flavours 59 Emulsifiers 59 Colours 65 Flavours 75 Reference 80 Chapter 5 Confectionery Plant 81 Steam Injection Cooking 82 Vacuum Cooking 83 Continuous Plant 84 Chapter 6 Sugar Glasses in the Chemistry of Boiled Sweets 85 The Formulation of Boiled Sweets 86 Manufacturing Processes for Boiled Sweets 88 Chapter 7 Grained Sugar Products 92 Fondant 92 Fudge 93 Chocolate-covered Liqueur Sweets 93 Chapter 8 Pan Coating 95 Hard Panning 96 Soft Panning 97 Problems in Coating Almonds and Other Nuts 98 Glazing and Polishing 98 Process Control Systems 99 Automated Systems 99 Contents 1x Chapter 9 Toffees and Caramels 101 Cooking Toffees 102 A Typical Toffee 103 The Process 106 Toffee as an Ingredient of Other Products 108 Chapter 10 Gums, Gelled Products and Liquorice 110 Pastilles, Gums and Jellies 110 Making Gums and Jellies 112 Liquorice 118 Chapter 11 Chewing Gum 124 Gum Base Characteristics 124 Texturisers 125 Antioxidants 125 Sugars 125 Loss or Gain of Moisture 126 Flavours 127 Chapter 12 Aerated Products 128 Marshmallows 128 Nougat 129 Chapter 13 Sugar-free Confectionery 131 Laxative Effects 132 The Sugar Substitutes 133 Making Sugar-free Products 138 Reducing the Energy Content 139 Sugar-free Products 139 Controlled Calorie Products 142 X Contents Chapter 14 Lozenges 144 Making Lozenges 145 Drying 145 Cream Paste 146 Chapter 15 Tabletting 148 Granulation 148 Avoiding Granulation 150 Tablet ting Additives 150 Chapter 16 Experiments 151 Health and Safety 151 Sugar Crystallisation Experiments 151 Lozenge Making 153 Fudge (or Grained Caramel) 154 Chapter 17 The Future 157 Subject Index 158 Chapter 1 Introduction The confectionery industry divides confectionery into three classes: chocolate confectionery, flour confectionery and sugar confectionery.
Chocolate confectionery is obviously things made out of chocolate. Flour confectionery covers items made out of flour. Traditionally, and con- fusingly, this covers both long life products, such as biscuits, in addition to short-life bakery products. Sugar confectionery covers the rest of confectionery.
In spite of the above definition, liquorice, which does contain flour, is considered to be sugar confectionery. The confectionery industry has created many confectionery products that are a mixture of categories, e. a flour or sugar confectionery centre that is covered with chocolate. There is another category that is sometimes referred to as ‘sugar-free sugar confectionery’.
This oxymoron refers to products that resemble sugar confectionery products but which are made without any sugars. The usual reason for making these products is to satisfy special dietary needs. A better name might be ‘sugar confectionery analogues’. The manufacture of confectionery is not a science-based industry.
Confectionery products have traditionally been created by skilled crafts- man confectioners working empirically, and scientific understanding of confectionery products has been acquired retroactively. Historically, sugar confectionery does have a link with one of the science-based industries - pharmaceuticals. In the eighteenth century, sugar confec- tionery products were made by pharmacists as pleasant products because the active pharmaceutical products were unpleasant. The two industries continue to share some technology, such as making sugar tablets and applying panned sugar coatings.
There are products that although apparently confectionery are legally medicines. This usually applies to cough sweets and similar products. In the United Kingdom these products are regulated under the Medicines Act and require a product licence. This means that all the ingredients for the product are specified and cannot easily be altered.
The dividing line between confectionery and medicines is not uniform in all countries. 1 2 Chapter I One reason that confectionery making is not a science-based industry is the very long product life. The Rowntree’s fruit pastille was invented in 1879 and was first marketed in 1881. This product is still one of the leading sugar confectionery lines in the UK today (1999)’ and it appears that it will continue to be sold into the 21st century.
The man who invented it, Claud August Gaget, knew nothing of proteins or the peptide bond. In 1879 very little was known about proteins in scientific circles so there was no scientific basis from which to work. FOOD LAW Legislation affects all parts of the food industry. In Great Britain, modern food law developed from the Food and Drugs Acts.
Such legislation came about after an outbreak of arsenic poisoning among beer drinkers, the cause of which turned out to be the glucose that had been used in making the beer - the glucose had been prepared by hydrolysing starch with sulfuric acid. The acid had been made by the lead chamber process from iron pyrites which contained arsenic as an impurity. The approach subsequently adopted was that all foods should be ‘of the substance and quality demanded’. This was obviously intended to cover any future problems with other contamination, and not necessarily with arsenic.
Other countries, particularly those whose legal systems follow Roman rather than Anglo-Saxon law, have tended to more prescriptive laws. The British approach is to allow any ingredient that is not poisonous unless, of course, the ingredient is banned. Additives are regulated by a positive list approach: unless the substance is on the permitted list it cannot be used. There are anomalies where a substance can be legal in foods but which is not permitted to be described in a particular way.
An example of this is the substance glycherrzin, which is naturally present in liquorice and has a sweet flavour. It would be illegal to describe it as a sweetener as it is not on the permitted sweetener list. Glycherrzin is permitted as a flavouring, however, and can be added to a food, which makes the overall product taste sweeter than it would without the addition. Conversely, the protein thaumatin is permitted as an intense sweetener yet, in practice, it has been found that thaumatin has more potential as a flavouring agent.
It would have been much easier and cheaper to obtain approval for thaumatin as a flavouring rather than as a sweetener. The British system does not automatically give approval to new ingredients merely because they are natural. This is in contrast with the position in some other countries - there will always be grey areas. One example is the position of the oligo-fructose polymers which are naturally present in chicory.
Chicory is undoubtedly a traditional food Introduction 3 ingredient; however, the oligo-fructoses extracted from it cannot neces- sarily be described as such. If the fructose polymers are hydrolysed to fructose then that is a permitted food ingredient. However, if they are partially hydrolysed then what is the status of the resulting product? The issue of fructose polymers is further complicated because one of the properties that is interesting is that they might not be completely metabolised. If that is the case then they would be considered as additives rather than ingredients.
Additives need specific approval whereas ingre- dients do not. Unlike chocolate confectionery, sugar confectionery is free of legal definitions. Terms such as ‘pastille’ or ‘lozenge’ although they have an understood meaning, at least to those in the trade, are sometimes applied to products that are not strictly within that understood meaning, e. there are products that are sold as pastilles but which are, in fact, boiled sweets.
Butterscotch must contain butter, but gums do not have to contain any gum. THE SCOPE OF SUGAR CONFECTIONERY The confectionery industry is vast. It ranges from small shops, where the product is made on the premises, to branches of the largest companies in the food industry. Probably because sugar confectionery keeps well without refrigeration it has been a global market for many years.
In spite of this there are distinct national and local tastes in sugar confectionery. A British jelly baby may resemble a German Gummi bear but the taste is quite different - curiously, the British jelly baby was invented by an Austrian confectioner. Similarly, the gum and gelatine pastilles made in France and Britain are very different, yet the leading British brand was invented by a French confectioner. HEALTH AND SAFETY Sugar confectionery is not an inherently dangerous product but several points should be made.