Sugar confectionery and chocolate manufacture

Sugar Confectionery and Chocolate Manufacture


Sugar Confectionery
and
Chocolate Manufacture
R LEES

E B JACKSON

BLACKIE ACADEMIC & PROFESSIONAL
An Imprint of Chapman & Hall

London . Glasgow· New York . Tokyo . Melbourne· Madras


Published by Blackie Academic & Professional, an imprint of
Chapman & Hall, Wester Cleddens Road, Bishopbriggs, Glasgow
G64 2NZ, UK
Chapman & Hall, 2-6 Boundary Row, London SEl 8HN, UK
Blackie Academic & Professional, Wester Cleddens Road, Bishopbriggs,
Glasgow G64 2NZ, UK
Chapman & Hall, 29 West 35th Street, New York NYl 0001, USA
Chapman & Hall Japan, Thomson Publishing Japan, Hirakawacho
Nemoto Building, 6F, 1-7-11 Hirakawa-cho, Chiyoda-ku, Tokyo 102,
Japan
DA Book (Aust.) Pty Ltd, 648 Whitehorse Road, Mitcham 3132, Victoria,
Australia
Chapman & Hall India, R. Seshadri, 32 Second Main Road, CIT East,
Madras 600 035, India
First edition 1973

Reprinted 1980, 1983, 1992

©

1973 R. Lees and E.B. Jackson

Softcover reprint of the hardcover 1st edition

1992

ISBN-13: 978-1-4684-1497-4
e-ISBN-13: 978-1-4684-1495-0
001: 10.1007/978-1-4684-1495-0

Apart from any fair dealing for the purposes of research or private study,
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should be sent to the publishers at the Glasgow address printed on this
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The publisher makes no representation, express or implied, with
regard to the accuracy of the information contained in this book and
cannot accept any legal responsibility or liability for any errors or
omissions that may be made.
A catalogue record for this book is available from the British Library

Contents

Page

FIGURES

xiii

PLATES

xv

PREFACE

1
1.1
1.2

xvii

1
1
1
5
5
7
8
9

1.4
1.5
1.6
1.7
1.8
1.9
1.10
1.11

BASIC TECHNICAL CONSIDERATIONS
Introduction
Moisture and Total Solids Content
Total Solids and Total Soluble Solids
Sugars and Sugar Solubility
Equilibrium Relative Humidity
Acid Content
pH
Gelling Agents
Viscosity
Texture
Crystallisation

12
13

2
2.1
2.2
2.3

2.4
2.5
2.6
2.7
2.8
2.9
2.10
2.11
2.12
2.13
2.14

SUGARS AND RELATED MATERIALS
Cane and Beet Sugar
Honey
Glucose Syrup
Starch Hydrolysates
Liquid Sucrose and Mixed Sugar Syrups
Dextrose
Fructose
Maltose
Invert Sugar
Invertase
Lactose
Caramel
Spray Dried Caramel
Sorbitol

15
15

20
22
34
36
37
40
40
41
41
42
42
43
44

1.3

v

11
11


vi

CONTENTS
Page

2.15
2.16

Glycerine
Malt Extract

45
46

3
3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
3.10
3.11
3.12
3.13

COCOA BEANS
Growth
Types
Sources
Cocoa Fruit
Harvesting
Pulp
Fermentation
Drying

Diseases of Cocoa
Storage of Cocoa Beans
Storage Pests
Chocolate Flavour and Aroma
Bean Quality

47
47
47
48
48
51
51
51
53
53
54
54
55
55

4
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8

4.9
4.10
4.11
4.12
4.13
4.14
4.15
4.16

FATS AND RELATED INGREDIENTS
General
Borneo Illipe (Illipe-Butter, Borneo Tallow)
Coconut Oil
Groundnut Oil (Peanut Oil, Earthnut Oil)
Palm Oil
Palm Kernel Oil
Butter
Off-flavours in Fats
Antioxidants
Oilseed Lecithins
Lecithin YN and other Synthetic Viscosity Reducing Agents
Glyceryl Monostearate
'Span' and 'Tween' Esters
Release Agents
Acetoglycerides
Waxes

57
57
58

58
58
59
59
59
61
61
62
62
63
64
64
64
65

5
5.1
5.2
5.3
5.4
5.5
5.6
5.7

MILK AND MILK PRODUCTS
Milk
Condensed Milk
Condensed Whey
Dried Milk Powders
Sodium Caseinate

Lactose
Butter

66
66
66
69
69
72
72
72


CONTENTS

vii
Page

6
6.1
6.2
6.3
6.4
6.5
6.6
6.7
6.8
6.9
6.10
6.11

6.12
6.13
6.14
6.15
6.16
6.17
6.18
6.19

GELLING AND WHIPPING AGENTS; GUMS
Confectionery Starches
Modified Starches
Types of Maize Starch
Zein
Pectin
Gelatine
Agar Agar
Whipping Agents
Egg Albumen
Gelatine Hydrolysate
Whipping Agents based on Milk Protein
Whipping Agents based on Soya Proteins
Carrageenan
Chicle
J elutong-Pontianak
Guar Gum
Arabinogalactan (Larch Gum)
Quince Seed Gum
Properties of Whipping, Gelling and Thickeni.,g Agents

7
7.1
7.2
7.3
7.4
7.5
7.6
7.7
7.8
7.9
7.10
7.11
7.12
7.13
7.14
7.15
7.16
7.17
7.18
7.19
7.20
7.21

FLAVOURING AND COLOURING AGENTS
Flavourings
Essential Oils
Essences
Fruit Juices
Fruit Purees or Pulps
Powdered Flavours

Artificial Cherries
Dates
Date Syrup
Figs
Ginger
Liquorice
Nuts
Almonds
Brazil Nuts
Cashew Nuts
Sweet Chestnuts
Coconut
Hazel Nuts
Macadamia Nuts
Pecan Nuts

73
73
80
81
83
83
86
89
90
90
91
91
92
93

93
96
96
96
96
96
97
97
98
99
99
99
100
100
100
101
101
101
102
103
103
105
105
106
106
107
108
108

viii CONTENTS
Page

7.22
7.23
7.24
7.25
7.26
7.27
7.28
7.29
7.30
7.31
7.32
7.33
7.34
7.35
7.36
7.37
7.38
7.39
7.40
7.41
7.42

Peanuts
Pistachio Nuts
Walnuts
Sultanas
Currants

Raisins
Vitamins
Confectionery Acids and their Salts
Citric Acid
Sodium Citrate
Tartaric Acid
Cream of Tartar
Lactic Acid
Calcium Lactate
Acetic Acid (Ethanoic Acid)
Malic Acid
Benzoic Acid
Sodium Benzoate
Sorbic Acid
Sodium Propionate
Colour

108
109
109
110
110
110
111
112
113
113
114
114
114

115
115
115
115
115
117
117
117

8
8.1
8.2
8.3
8.4
8.5
8.6
8.7
8.8
8.9
8.10
8.11
8.12

COCOA, CHOCOLATE AND RELATED PRODUCTS
Sequence of Processes
Cleaning
Roasting
Chocolate Recipes
Milk Crumb
Winnowing

Cocoa Powder
Mixing/Melangeur Process
Refining
Conching
The Tempering of Chocolate
The Application of Span 60 and Tween 60 in Sweet Dark
Chocolate
Moulding
Fat Migration
Storage of Chocolate
Nutritional Value of Chocolate
Bulk Deliveries of Chocolate
Liqueur Chocolates
The Tropical Warehouse Moth

119
119
119
119
124
126
128
130
132
133
136
139

8.13
8.14

8.15
8.16
8.17
8.18
8.19

146
151
153
153
154
154
155
159


CONTENTS

ix

Page

9
9.1
9.2
9.3
9.4
9.5
9.6
9.7

9.8
9.9
9.10
9.11
9.12
9.13
9.14

BOILED SWEETS
Characteristics
The Production of High-boiled Sweets
Chemical Changes during Boiling
Invert Sugar in High-boiled Sweets
Batch Cooking
Batch Type Early Vacuum Process
Recipes for High-boiled Confections
Lett<:red or 'Seaside' Rock
Continuous Dissolving Methods
Continuous Cooking Methods
Continuous Vacuum Cooking
Deposited High-boiled Sweets
Pump Filling
Powder Filling

161
166
167
168
168
169

169
172
176
177
181
183
186
187

10
10.1
10.2
10.3
10.4
10.5
10.6
10.7
10.8
10.9
10.10
10.11

CARAMELS, TOFFEES AND FUDGE
Caramels and Toffees
Modifications to the Basic Recipe
Dulce de Leche
Caramel Recipe Compilation
Continuous Manufacture of Caramels
Properties of Caramels
Packaging and Storage

Export Caramels
Fudge
Variations on Basic Vanillin Fudge
Composition of Fudge

191
191
192
192
193
198
201
203
203
206
206
208

11
11.1
11.2
11.3
11.4
11.5
11.6
11.7

FONDANTS, CREAMS AND CRYSTALLISED CONFECTIONERY
Fondants, Creams and Crystallised Confectionery
Production of Fondant

Creams
Composition of Creams and Fondants
Wet Crystallisation
Candied Fruit and Peel
Crystallised and Preserved Ginger

211
211
212
213
215
218
219
222

12
12.1
12.2
12.3
12.4
12.5

GUMS, JELLIES AND PASTILLES
Production
Processes for Gums and J elIies
Modification of Recipes for Continuous Production
Starch Drying and Conditioning
Glazing of Gums

226

226
227
232
232
234

161


X

CONTENTS
Page

12.6
12.7
12.8
12.9
12.10
12.11
12.12
12.13
12.14
12.15
12.16
12.17
12.18
12.19
13
13.1

13.2
13.3
13.4
13.5
13.6
13.7
13.8
13.9
13.10
14
14.1
14.2
14.3
14.4
14.5
14.6
14.7
14.8
14.9
15
15.1
15.2
15.3
15.4

Starch Moulding Machines of the Mogul Type
Other Points in Production
Starch, Gum Jellies and Pastilles by Atmospheric Cooking
Methods
Starch Jellies for Continuous Production

Gelatine Jellies
Production of Gelatine Jellies
Fruit Pastilles
Tablet Jellies
Jelly Drops
Gum Arabic Gums
Turkish Delight
Agar Jellies
The Use of Powdered Pectins in Confectionery Manufacture
Low Methoxyl Pectin Jellies

236
238

LIQUORICE AND CREAM PASTE

269
269
269
271
272
274
279
280
281
282
283

Liquorice
Methods for Manufacturing Liquorice Paste

Properties of Liquorice Paste
Composition of Liquorice
Processing Liquorice Paste
Cream and French Paste
Processing Cream Paste
Composition of Cream Paste
Extrusion of Cream Paste
Liquorice Allsorts
TABLETS. LOZrNGFS AND EXTRUDED PASTE

Tablets
Slugging
Tablet Composition
Manufacture of Tablets
Lozenges
Composition of Lozenges
Production of Lozenges
Sweet Cigarettes
Production Control for Sweet Cigarettes
MARSHMALLOW AND NOUGAT

Marshmallow Confections
Frappe based on Egg Albumen, containing Starch
Gelatine Marshmallow
Continuous Production of Marshmallow using Gelatine

239
239
240
241

243
244
251
251
254
257
260
265

286
286
287
287
289
291
292

293
294
296
299
299
300
302
303


CONTENTS

xi

Page

15.5
15.6
15.7
15.8
15.9
15.10
15.11
15.12
15.13

Egg Albumen Marshmallow
Modification of Recipes for Continuous Production
Nougat
Nougat using Egg Albumen
Nougat using Gelatine
Nougat using a Vertical Planetary Mixer
Nougat using Pressure Beating
Nougat using Malto-dextrins
Continuous Production of Nougat

308
309
316
317
317
318
319

320
321

16
16.1
16.2
16.3
16.4
16.5
16.6
16.7
16.8
16.9
16.10

OTHER CONFECTIONERY TYPES
Panning
Hard Pan Work
Polishing
Silver Coating
Chocolate Coating
Soft Panning
Chewing Gum
Sugarless Chewing Gum
Bubble Gum
Marzipan and Persipan

324
324
325

328
329
330
330
332
336
336
337

17

17.7
17.8
17.9
17.10
17.11
17.12

CALCULATING SUGAR CONFECTIONERY AND CHOCOLATE
RECIPES
Calculation of Recipes from Analytical Results
Effect of Inversion
Effect of Milk Solids
Effect of Moisture Loss on Jelly Goods
Replacement Weight of Scrap Syrup
Calculation of Probable Analytical Composition from the
Confectionery Recipe
Calculation of Syrup and Crystal Phase
Sugar Content of the Syrup Phase
Calculation of Boiling Temperature

Calculation of Chocolate Recipes
Count (Number of Confections) per Unit Weight
Determination of Equilibrium Relative Humidity (e r h)

345
348
349
350
351
356
357

18

GENERAL REFERENCE TABLES

360

19

GLOSSARY

364

ApPENDIX

369

INDEX

371

17.1
17.2
17.3
17.4
17.5
17.6

340
340
343
343
344
344


List of Figures

Page

1
2
3
4
5
6
7
8
9

Basic crystal shape of sucrose
Glucose syrup manufacture (batch process)
Manufacture of dextrose
Production of sweetened condensed milk
Microscopic appearance of six common starches
Wet milling of maize
Starch drying
Manufacture of modified starches
Manufacture of pre-gelatinised starches
10
Treatment of cocoa beans
11
Manufacture of cocoa powder
12
Flow sheet for chocolate manufacture
13
Manufacture of milk crumb
14
Single-stream continuous tempering and enrobing of
chocolate
15
Sollich tempering unit feeding enrober
16 (a) Otto Hansel sugar cooker
16 (b) Early vacuum cooker design
17
Formation of lettered 'rock'
18-20 Letters for 'rock'
21
Theegarten 01 continuous dissolver

22
Microfilm cooker
23
Moisture content of microfilm cooked sugar
24
Take-off points on a candy maker
25
Baker Perkins continuous candy maker unit
26
Otto Hansel Sucromat vacuum cooker
27
Production of deposited boiled sweets
28
Baker Perkins continuous caramel plant
29
Check-list of caramel faults
30
Daniels unimix cooker
31
Votator heat transfer plant
xiii

13

24
39
68
73
79
80

81
81
120
121
122
127
142
144
168
169
173
174
176
178
179
181
182
183
185
199
205
230
231


xiv

LIST OF FIGURES
Page

32
33
34
35
36
37
38
39
40
41 (a)
41 (b)
42
43
44
45
46
47
48
49
50
51
52

Ter Braak jet cooking system
NID brushless candy cleaner
NID continuous sugar sanding machine
NID high-speed moulder
Production of table jellies
Check-list of table jelly faults: A (manufactured)
Check-list of table jelly faults: B (made up)

Check-list of liquorice faults
Check-list of tablet faults
Production of lozenges
Check-list of lozenge faults
Go-no-go gauge
Oakes mixing head
Whizolator for marshmallow production
Turbomat arrangement for marshmallow production
Continuous production of egg albumen marshmallow
Continuous production of extruded marshmallow
Batch production of nougat by Ter Braak Presswhip
Continuous production of nougat
Check-list of sugar-panned goods faults
Nomogram for calculating e r h of sugar syrups
Nomogram of cream paste sample

233
235
237
237
245
248
248
278
290
293
295
297
304
306

307
310
311
321
321
331
357
358


List of Plates

Split cocoa pod showing beans
2 Ter Braak Coolmix
3 Baker Perkins continuous microfilm cooker
4 Baker Perkins multi high-boiled sweet depositor
5 Baker Perkins continuous caramel plant
6 Ter Braak Presswhip
7 Steinberg twin spray unit in pan room

xv


Preface

The authors had five objectives in preparing this book: (i) to bring together
relevant information on many raw materials used in the manufacture of
sweets and chocolate; (ii) to describe the principles involved and to relate
them to production with maximum economy but maintaining high quality;
(iii) to describe both traditional and modern production processes, in particular those continuous methods which are finding increasing application;

(iv) to give basic recipes and methods, set out in a form for easy reference,
for producing a large variety of sweets, and capable of easy modification to
suit the raw materials and plant available; (v) to explain the elementary
calculations most likely to be required.
The various check lists and charts, showing the more likely faults and
how to eliminate them, reflect the fact that art still plays no small part in
this industry.
To help users all over the world, whatever units they employ, most formulations are given in parts by weight, but tables of conversion factors are
provided at the end of the book.
There also will be found a collection of other general reference data in
tabular form; while the Glossary explains a number of technical terms,
many of them peculiar to the industry.
This is a time of world-wide change in the structure of the sugar confectionery and chocolate industry. It is experiencing consolidation with a
general movement towards larger manufacturing units employing less labour
with higher investment and capital costs in automatic and continuous highoutput production lines.
Many old-established factories have been closed because of mergers or
takeovers or changing market pressures. But new, small vigorous companies
have been formed to manufacture lines which the larger firms are finding
uneconomic to produce in batch quantities. Confectionery packs offered
under the retailer's own label are accelerating the change to more efficient
xvii


xviii

PREFACE

production to cope with the lower profit margins generally associated with
this trade. New firms entering the industry have high sales potential provided
a good product is offered, effectively packaged and efficiently marketed.

Sales of confectionery products in the United Kingdom are considerable, as
the following figures for 1971 show.
Chocolate and chocolate
confectionery
Chocolate crumb, cocoa butter and
other cocoa products
Chocolate couverture and similar
products
Medicated confectionery
Sugar confectionery

Producers
£

United Kingdom
Imports
£

182169000

Exports
£

4197000

16984000

12402000 20136000

3666000

12163000
1 810 000
108248000

63000

472000
187000
3 208 000 14 610 000

(Source: Business Monitor, June 1972, HMSO.)

Sales by United States manufacturers during 1970 were 1925 million
dollars of which 770 million dollars were direct sales to retailers (Source:
US Industrial Outlook, US Department of Commerce).
Sales of sugar confectionery and chocolate in 1968 in the EEC (the
original 6) were £244 million and £388 million respectively (Economist
Intelligence Unit Reports 95, 98, 101, 113).
Both authors acknowledge the help and encouragement of many friends
and colleagues: to Alan Maiden who has given considerable encouragement
and assistance over several years and especially of their wives for their
patience and tact during the writing. Ronald Lees wishes to thank Mr.
Frank Cruden, Editor of Confectionery Production, for permission to reproduce tables from his articles in that journal under the nom de plume
John F. Ingleton. The following individuals most kindly gave information
and permission to reproduce illustrations:
Dr. J. Buckle, HP. Bulmer Co. Ltd., Hereford, England.
Mr. B. W. Minifie, Knechtel Laboratories Ltd., Saltford, Bristol, England.
Mr. J. W. Mansvelt, Lenderlnk Co., N.V., Schiedam, Holland.
Dr. A. M. Maiden, CPC (United Kingdom) Ltd., Esher, Surrey, England.

Mr. P. Fawcett, CPC (United Kingdom) Ltd., Esher, Surrey, England.
Mr. J. Reid, E. T. Oakes Ltd., Macclesfield, England.
G. A. Steele, Baker Perkins Ltd., Peterborough, England.
Mr. C. Warren, Confectionery Development Ltd., Hemel Hempstead,
Hertfordshire, England.
The directors and staff of CPC (United Kingdom) Ltd., Manchester and
Esher, England.


PREFACE

xix

Information. illustrations and/or photographs on machinery and manufacturing process are warmly acknowledged also from the following companies:
Bramigk and Co. Ltd .• London. E.3.
Cadbury Schweppes Ltd., BournvilIe, Birmingham.
Otto Hansel GmbH, Hannover, Germany.
Hamac Hansella, GmbH, Viersen, Germany.
R. Simons and Sons Ltd., Basford, Nottingham.
Norman Bartleet Ltd., London W14.
Gebr. er Braak N.Y., Rotterdam, Holland.
Justus Theegarten, Koln, Germany.
Winkler Dunnebier, Neuwied/Rhein, Germany.
Sollich OHG, Bad Salzuflen, Germany.
Lenderink Co. N.Y., Schiedam, Holland.
Bulmer Co. Ltd., Hereford, England.
E. T. Oakes Ltd., Macclesfield, England.
G. A. Steele, Baker Perkins Ltd., Peterborough, England.
Confectionery Development Ltd., Hemel Hempstead, Herts, England.

1
Basic Technical Considerations

1.1

INTRODUCTION

Some understanding of the chemical and other scientific properties of sugar
confectionery and chocolate is important for the technologist; notably in
overcoming faults that may have developed in the product; in the preparation of matching recipes; for detecting wrong blending of ingredients or
incorrect processing conditions; and in the maintenance of high standards
of quality.
Throughout the book reference is made to such general scientific concepts as moisture content, pH, etc. This introductory chapter is intended to
describe: briefly the more important of these and their significance to the
properties of confectionery.
1.2

MOISTURE AND TOTAL SOLIDS CONTENT

The amount of water left in a sugar confectionery product depends on
the type of raw materials used and on the extent of the processing during
manufacture. When water is heated under normal atmospheric conditions
it will boil at 100° C (212° F); but this boiling temperature is increased
when sugar is present in solution. For a fixed concentration of sugar, under
standard conditions of atmospheric pressure, a solution will always boil at
the same temperature. Conversely if a sugar solution is boiled to a fixed
temperature under standard conditions the remaining liquor will always
contain the same percentage concentration of sugar and water. The increase
in boiling temperature for varying concentrations of sucrose is shown in

Table 1.
The effect of other sugars (which are described in Chapter 2) in raising
the boiling point is shown in Table 2 and the effect of boiling under vacuum
in Table 3.
Before the general availability of thermometers, a number of crude tests
were used to determine boiling level. To enable the reader to use older
recipes, these are set out in Table 4.
1
R. Lees et al., Sugar Confectionery and Chocolate Manufacture
© R. Lees and E. B. Jackson 1973


2

SUGAR CONFECTIONERY AND CHOCOLATE MANUFACTURE

TABLE 1. Boiling Point of Sucrose (Cane or Beet Sugar) Solutions
Sucrose
Concentration

%

°C

40

101·4
102
103
105·5

108
111
116
122
130

50
60
70
75
80
85
90
95

Boiling Point

of

214'5
215·5
217·5
222
227
232
241
252
266

The presence of other raw materials, such as fats, non-sugar milk solids,

starch etc., does not significantly affect the boiling temperature. It is
therefore possible to determine the boiling points used in the manufacture
of a competitor's confection through a knowledge of the composition and,
in particular, the water content (see also §17.10).
A knowledge of the water (moisture) content of a raw material is
important in developing confectionery recipes. In the United Kingdom it
is necessary to incorporate more than 4% butterfat in any sweet which
contains in its title the word 'butter'. If the weight of butter added was
divided by the batch weight after processing, an erroneous value for the
percentage butter content would be calculated, for butter contains some
water and this must be taken into account when developing recipes which
contain this ingredient (see also § 17.2).
The water left in a confection can also influence its storage behaviour in
a number of ways: e.g. whether or not the product will dry out or pick up
moisture in store, and the extent of crystallisation occurring during its
expected shelf life. Boiled sweets which contain more than 4'0% moisture
will normally crystallise (grain) while in store. Average moisture content for
a range of sugar confectionery products and raw materials is shown in
Table 5.
TABLE 3. Effect of Boiling under Vacuum
Approximate
Total Solids Value

%

Open Boil Temp.
DC
OF

96

97
98

143·4
150
160'1

290
302
320

Vacuum Cooking
Boiling Temp.
Vacuum
°C
OF
Ib/in 2

129·5
135
140·6

265
275
285

25
27
28

%

81·0
85·6
89·3
92'7
97'8

OF

222
232
241
252
266

105'5
111'1
116'1
122'2
130'0

Glucose Syrup
Concentration

°C

Temperature

1 :1
76·5
81·2
85'5
90·0
95·5

2:1
78·0
82'7
86·7
90·9
96·2

79·2
83-8
87·8
91-6
96·9

1:2
75'0
79'7
84'2
89'1
94·7

Invert Sugar

Glucose Syrup Solids

4:1

Ratio

73·8
77·6
83·1
88·4
94'0

1 :4

%

72'0
76'8
81-6
87-3
93·1

Invert Sugar
Concentration

TABLE 2. Boiling Temperatures of Glucose Syrup and Invert Sugar Syrups and Mixtures thereof

w

i~

~

!

~

()


4

SUGAR CONFECfIONERY AND CHOCOLATE MANUFACTURE

TABLE 4. Traditional Degrees of Sugar Boiling

Name

Test

Thread (gloss)
Large Thread (large gloss)

A
A

Small Pearl

B

Large Pearl

B

Blow (souffle)

C

Feather

B

Small Ball

B

Large Ball

B

Light Crack
Medium Crack

B
B

Hard Crack

B

Extra Hard Crack

B

Caramel

B

Observation
Thin strands
Stronger and
more strands
Forms small
droplets
Forms large
droplets
Bubbles set
on syrup
Forms feathery
hard strands
Syrup forms
soft ball
Syrup forms
hard ball
Forms thin sheet
Sheet forms,
slightly brittle
Rapidly formed
sheet
Sheet shows signs
of browning

Brown brittle
sheet forms

Approx. Temp.

°c

OF

103
104

215
219

105

220

106

222

110

230

111

232

116

240

120

248

129
133

264
271

143

289

168

334

180

356

Tests: A. Place sample of cooked syrup between two wetted fingers and open.

B. Dip finger or spatula (above 110 0 C) in water, then in portion of boil, return to

cold water. C. Blow on spatula dipped in syrup.

1.3

TOTAL SOLIDS AND TOTAL SOLUBLE SOLIDS

The total solids content of a sweetmeat includes all the solid matter in
the ingredients used for the recipe. Total soluble solids content includes
only those components which are soluble in water. It is therefore mainly
composed of the added sugars and as such is a useful guide as to whether
the product is liable to ferment on store or whether correct processing conditions have been used. A sufficiently accurate determination of total soluble
solids content can be made during manufacture of jellies and similar products using a pocket sugar refractometer.
1.4

SUGARS AND SUGAR SOLUBILITY

A range of sugar ingredients are used in the manufacture of sweets and
chocolates. These include cane and beet sugar, glucose syrups, high sugar
content syrups such as treacle and honey, invert sugar syrups, dextrose,


BASIC TECHNICAL CONSIDERATIONS

5

TABLE 5. Typical Percentage Moisture Content of Sugar Confectionery,
Chocolate and Various Raw Materials

Sweet

Agar Jellies
(High) Boiled Sweets
Butterscotch
Candied Fruit
Caramels
Chocolate
Creams
Cream Paste
Fondant
Fudge
Gelatine Jellies
Jellies Agar
Component
Agar
Block Liquorice Juice
Brown Sugar
Butter
Candied Peel
Chocolate
Chocolate Crumb
Citric Acid, Hydrate
Condensed Milk
Cornflour
Dates
Dextrose Hydrate
Fruit Pulp
Gelatine
Glucose Syrup
Low DE*
Regular

High DE

Sugar Confectionery and Chocolate
Sweet
Moisture %
24·0 Jellies Gelatine
2·0 Jellies Pectin
3'5 Jellies Table
20·0 Liquorice Paste
8'0 Lozenges
1'0 Marshmallow grained
14·0 Marshmallow cast
6·0 Nougat
12-0 Pectin Jellies
7·0 (Compressed) Tablets
22'0 Turkish Delight
24·0
Moisture

Raw Materials
%
Component
16·0
Maltose
Enzyme
18·7
2·9 Golden Syrup
13-8 Granulated Sugar
20·0 Gum Arabic
1·0 Gum Tragacanth

1·0 Honey
8·3 Icing Sugar
27·0 Invert Sugar
12·3 Lactose
24·8 Milk Powder
9'1 Nuts
39·8 Sorbitol
12·3 Soya Flour
Starch
19·4 Tartaric Acid
18'7 Treacle
18·0 Wheat Flour

Moisture

Moisture

%

22·0
22·0
25·0
18·0
1'5
12·0
18'0
8·0
22·0
1·0
20·0

%

16·7
16'7
16·7
0·01
9·9
9·9
18·0
0·01
28·0
0·1
22·9
2·0
30·0
7·4
10'7

1·0
18·8
13-8

*DE = dextrose equivalent (see §2.3)

fructose and lactose. Cane or beet sugar (sucrose), dextrose (sometimes
called glucose), fructose (sometimes called laevulose) and lactose (sometimes
called milk sugar) are single sugars; all others are mixtures of sugars.
Glucose syrup contains dextrose, maltose and a range of complex sugars
while invert sugar is a mixture of dextrose and fructose. Properties of

various types of confectionery sugars are considered in more detail in
Chapter 2.
Sugar confections which contain high concentrations of cane or beet
sugar (sucrose) may crystallise (grain) during manufacture or while on store.
Although this may be desired for certain products. e.g. fondants. fudge. in


6

SUGAR CONFECTIONERY AND CHOCOLATE MANUFACTURE

other cases it is a quality defect. If the level of sucrose is lowered to under
75% in a confection, such as a jelly, to lessen the danger of graining, then
the product becomes liable to mould and yeast growth. Both defects can
be cured by the addition of the so called 'doctor-sugars', usually glucose
syrup and invert sugar syrup (see §2.3 and §2.9), which inhibit crystallisation and raise the overall level of sugars in solution.
Doctor sugars have the ability to break down certain types of complex
chemical compounds; because of this they are said to have reducing properties. Various analytical techniques are used to determine reducing
sugar content usually based on breaking down compounds containing
copper [see R. LEES, Laboratory Handbook of Methods of Food Analysis,
1971, Leonard Hill Books]. Practically all the solid matter present in an
invert sugar syrup is made up of reducing sugars but only a part of the
glucose syrup solids are of this type. Determinations on glucose syrup are
carried out as though the only reducing sugar present is dextrose. For comparative purposes a dextrose equivalent (DE) value is quoted for this sugar
mixture which indicates the equivalent amount of dextrose present in the
dried syrup that would give the same chemical behaviour during analysis.
The amount of reducing sugars in a sugar confection is important in indicating how well the recipe has been balanced (Chapter 17).
Table 6 shows that at 20° C a pure saturated solution of sucrose (cane
or beet sugar) can only hold 67% of solids but that progressive additions
of invert sugar increases this figure. This increase in total solids content

produces improved non-crystallising characteristics and builds up a resistance to microbiological attack. As the amount of invert sugar is increased,
the syrup becomes saturated with respect to dextrose (a component of
invert sugar).
The effect obtained using invert sugar to increase syrup concentration is
limited: Table 7 shows that beyond 52% invert syrup, the solids content
decreases although crystallisation may still remain acceptable.
The most effective method of 'doctoring' is to use glucose syrup (see
TABLE 6.

Concentration of Sucrose/Invert Sugar Syrups Saturated with respect
to Sucrose
Solids Present

Sucrose

%

100
78·6
67'6
57·6
48·8

Invert Sugar

%

o

21·4

32-4

42'4
51·2

Solids Content of Solutions
just Saturated with Sucrose
at 20° C (68° F)
% by weight

67'1
70·0
72-0
74'0
76·0


BASIC TECHNICAL CONSIDERATIONS

TABLE 7.

7

Concentration of Sucrose/Invert Sugar Syrups Saturated with respect
to Invert Sugar

Sucrose

Invert Sugar

%

Solids Content of Solutions
just Saturated with Dextrose
at 20° C (68°P)
% by weight

47·5
40'0
30·0
20·0

52·5
60·0
70·0
80·0

76'1
73·6
70·5
67'7

Solids Present

%

TABLE 8. Concentration of Sucrose/Glucose Syrups Saturated with respect
to Sucrose

Solids Present

42 DE Glucose
Sucrose
Syrup Solids

%

%

o

100

78·6
67·6
57·6
48·8
40·9
34·1
28·4
23·7

21'4
32·4
42'4
51·2
59·1
65·9
71'6
76·3

Solids Content of Solutions
just Saturated with Sucrose
at 20° C (68° P)
% by weight
67·1
70·0
72-0
74'0
76·0
78·0
80·0
82'0
84·0

§2.3). Table 8 shows that a syrup solids content of 84% can be achieved
using a mixture of sucrose and 42 DE glucose syrup without sucrose or
dextrose crystallisation taking place.
In practice the situation is complicated by the fact that whilst sucrose
crystallises fairly readily from solution, dextrose monohydrate does not.
A certain amount of dextrose supersaturation can exist indefinitely provided that no dextrose monohydrate is present to initiate crystallisation
(or 'seed' the solution). Dextrose will not crystallise from unseeded solutions until the concentration is over 150% higher than that of the solubility
value.
1.5

EQUILIBRIUM RELATIVE HUMIDITY

The amount of moisture present in air is indicated by the relative
humidity value. This relates the amount of water present in the air with
the total amount of moisture that could be held if the air was fully saturated
under the same conditions. The moisture in the air contributes a measurable pressure to the total air pressure and a comparative value, known as

the relative vapour pressure (rvp), can be derived by relating the deter-


S SUGAR CONFECTIONERY AND CHOCOLATE MANUFACTURE
mined value to the maximum value known for moisture-saturated air under
the same conditions.
The temperature at which moisture condensation from the air occurs is
known as the dew point. An examination of the relative humidity and
temperature will enable an accurate prediction to be made of the point
at which moisture formation will occur. Moisture deposition is particularly
likely to occur for instance when chocolates leave the cooling tunnels after
coating. This deposited moisture can leach out some of the sugar present
in the chocolate coating, which later crystallises causing 'sugar bloom'.
The moisture in a sweetmeat will exert a vapour pressure on the
atmosphere which immediately surrounds the confection. A value relating
the amount of moisture present in the surrounding air to fully saturated
air can be calculated. When this value known as the Equilibrium Relative
Humidity (e r h), is equal to the relative humidity of the air, the product
neither gains nor loses moisture. If the e r h is below this the confection will gain moisture and if above, will lose it.
Confections with high equilibrium relative humidities, over 70%, when
packed in sealed containers give rise to conditions which encourage mould
growth during storage. Changes in temperature result firstly in moisture
loss from the confection and later deposition on the surface. Leaching of
sugars occur and the weak sugar syrup will permit the growth of mould.
A number of methods for the theoretical calculation of erh (or rvp)
have been suggested [J. W. GROVER, 1947, I. Soc. Chern. Ind., 66, 201-5],
[A. E. POUNCY, B. C. L. SUMMERS, 1939, I. Soc. Chern. Ind., 58, 162],
[PROCTOR LANDROCK, 1951, Food Tech., 5, 332-7], [E. G. GILES, 1955,
Confectionery Production, (1), 61] and practical methods for their determination developed [J. W. GROVER, 1947, I. Soc. Chern. Ind., 66, 201],
[J. KELLEHER, 1955, Int. Sugar I., 57,36-38], [R. W. MONEY, R. BORN, 1951,

I. Sci. Fd. Agric., April ISO], [R. S. NORRISH, 1964, Confectionery Production, 30 (10), 769-771, S08], [G. D'ALTON, 1962, Confectionery Manufacture,
S], [W. POERSCH, 1963, Starke, 15, (11), 405-12].
TABLE 9. Typical Equilibrium Relative Humidity Values of Sugar Confections
Confection

(High) Boiled Sweets
Caramels
Creams
Fondant
Fudge
Jellies
Liquorice
Marshmallow
Turkish Delight

Equilibrium Relative
Humidity %

less than 30

45-50
80-85
75-80
65-75
60-76
57-65

64-72

60-70

BASIC TECHNICAL CONSIDERATIONS

1.6

9

ACID CONTENT

Five acids are commonly used in sugar confectionery products: citric,
malic, tartaric, lactic, and acetic acids. The first four are said to be 'weak'
acids and they are used for flavouring. In laboratory reports, the analyst for
convenience commonly indicates the percentage of acid as if it were citric.
Additional tests are necessary to identify the particular acid used. As a
general rule confections with a mild fruit flavour should contain 0·5%
acid, those sold as fruit confections need 1'0% acid and those sold as acid
drops should have an acid content of between 1'5%-2'0%.
1.7

pH

A knowledge of the amount of acid present although helpful, is not
indicative of the real acid strength of the product. A solution of 1%
sulphuric acid has quite different chemical acidic properties from a 1%
solution of citric acid.
The strength of an acid is related to the amount of dissociated hydrogen
ions in solution. Pure water, H 20 can in simple terms be thought of as
dissociating into hydrogen H + and hydroxyl OH - ions. When acids are
present they cause a greater dissociation and therefore increase the number

of hydrogen ions present. Alkalis cause reassociation thereby lowering the
amount of free hydrogen ions. Different acids cause different levels of
dissociation. The full scientific explanation is more complex.
A scale has been devised-pH-which gives comparable whole values
for indicating the acidity or alkalinity of a wide range of products. This
scale expresses the logarithm of one, divided by the hydrogen ion concentration, so that the 'pH value' is lower, the more acid the solution. The
method was suggested by Sorensen in 1909 and has been widely adopted
in the food industry. pH is easily measured either by colour matching
changes in dyes under particular acid or alkaline conditions or, more
usually, by measuring changes in electrical conductivity.
A neutral solution has a pH of 7·0, lower values indicate an acid
solution, higher values an alkaline solution. A 0'6% solution of nitric acid,
a strong acid, has a pH of 1·0 while the same concentration of weak acetic
acid has a pH of 2·9; such variations are indicated in Table 10.
The pH scale runs from 0 to 14; it is possible only under exceptional
conditions to get pH values as low at 1·5 and as high as 14. Below pH 1
and above pH 13 the determined values are inaccurate. In sugar confectionery manufacture the scale readings lie mainly between pH 2 and pH 8.
To stabilise the acidity of a product, use is made of so-called buffer-salts,
compounds produced from strong alkalis and weak acids; notably sodium
citrate. In the presence of extra acid, the citrate ion re-combines to form