Chemistry and Technology of Soft Drinks and Fruit Juices
Beschreibung
Weitere Details
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Person
Dr Philip R. Ashurst, Ashurst and Associates, Consulting Chemists to the Food Industry, Ludlow, UK.
Inhalt
Contributors xv
Preface xvi
1 Introduction 1
P.R. Ashurst
1.1 Overview 1
1.2 Soft drinks 1
1.2.1 Ready-to-drink products 2
1.2.2 Concentrated soft drinks 2
1.2.3 Legislation 3
1.2.4 Product types 4
1.2.5 Development trends 6
1.2.6 Nutrition 7
1.2.7 New product trends 8
1.3 Fruit juices 8
1.3.1 Processing technology 9
1.3.2 Adulteration 10
1.3.3 Other processes 12
1.3.4 Nutrition 12
1.4 Packaging 13
1.5 Summary 14
References and further reading 14
2 Trends in beverage markets 15
E.C. Renfrew
2.1 Introduction 15
2.2 Definitions 15
2.3 Beverage consumption trends 16
2.3.1 Bottled water 17
2.3.2 Carbonated soft drinks 17
2.3.3 100% juices nectars and fruit drinks 19
2.3.4 Energy drinks 19
2.3.5 Ready-to-drink (RTD) tea and ready-to-drink coffee 20
2.3.6 Coffee 20
2.3.7 Tea 21
2.3.8 Beer 21
2.3.9 Wine 22
2.3.10 Milk and flavoured milks 22
2.4 Consumption charts 23
2.5 Regions and markets 25
2.6 Market share charts 26
2.7 Main drivers in consumption 28
2.7.1 The search for 'natural' 28
2.7.2 Adult soft drinks 29
2.7.3 Protein drinks 29
2.8 Conclusion 29
3 Fruit and juice processing 31
B. Taylor
3.1 Introduction 31
3.2 Fruit types 32
3.2.1 Botanical aspects and classification of fruit types 32
3.2.2 Harvesting considerations for berry citrus pome stone and exotic fruits 35
3.3 Fruit types for processing 36
3.3.1 Pome fruits 36
3.3.2 Citrus fruits 38
3.4 General comments on fruit juice processing 39
3.4.1 Processing of 'fleshy' fruits 40
3.4.2 The use of enzymes in fruit juice processing 43
3.4.3 Extraction of citrus juices 46
3.5 Juice processing following extraction 'cleaning' and clarification 48
3.5.1 Juice concentration by evaporation 49
3.5.2 Freeze concentration 50
3.5.3 Hyper- and ultrafiltration 50
3.6 Volatile components 51
3.6.1 Spinning cone column 52
3.6.2 Composition of fruit juice volatiles 53
3.7 Legislative concerns 54
3.7.1 European fruit juice and nectars directive and associated regulations 54
3.7.2 AIJN Guidelines 56
3.7.3 Labelling regulations and authenticity 57
3.7.4 Juice in the diet - 'five-a-day' 58
3.8 Quality issues 58
3.8.1 Absolute requirements 58
3.9 In conclusion 62
References and further reading 64
4 Water and the soft drinks industry 65
T. Griffiths
4.1 Usage of water in the industry 65
4.2 Sources of water 66
4.2.1 Water cycle 66
4.2.2 Surface water 67
4.2.3 Ground water 67
4.3 Quality standards relating to water 68
4.3.1 UK legislative standards 68
4.3.2 Internal and customer standards 68
4.4 Processing water 69
4.4.1 Required quality 69
4.4.2 Starting quality 72
4.4.3 Processing options 75
4.5 Analytical and microbiological testing of water 83
4.5.1 Chemical tests 83
4.5.2 Microbiological tests 84
4.6 Effluents 84
4.6.1 Potential contaminants of water waste 84
4.6.2 Use of 'grey' water 85
4.6.3 Clean-up and reuse of effluents 85
Further reading 87
References 87
5 Other beverage ingredients 88
B. Taylor
5.1 Introduction 88
5.2 Factors influencing development of the industry 88
5.3 The move towards standardisation 91
5.4 The constituents of a soft drink 94
5.5 Water 94
5.5.1 Requirements 94
5.5.2 Quality of fresh water 96
5.5.3 Water hardness 96
5.5.4 Water treatment 96
5.5.5 Water impurities and their effect 97
5.6 Acidulents 98
5.6.1 Citric acid 98
5.6.2 Tartaric acid 99
5.6.3 Phosphoric acid 100
5.6.4 Lactic acid 101
5.6.5 Acetic acid 101
5.6.6 Malic acid 101
5.6.7 Fumaric acid 101
5.6.8 Ascorbic acid 102
5.7 Flavourings 102
5.7.1 Flavourings and legislation 104
5.7.2 Flavourings in beverage application 106
5.7.3 Water-miscible flavourings 106
5.7.4 Water-dispersible flavourings 107
5.8 Colours 112
5.9 Preservatives 115
5.9.1 Microorganisms and beverages 116
5.9.2 Sulphur dioxide 117
5.9.3 Benzoic acid and benzoates 119
5.9.4 Sorbic acid and sorbates 119
5.10 Other functional ingredients 120
5.10.1 Stabilisers 120
5.10.2 Saponins 120
5.10.3 Antioxidants 121
5.10.4 Calcium disodium EDTA 121
5.11 Food safety 122
5.12 Future trends 123
Further reading and references 125
6 Non-carbonated beverages 126
P.R. Ashurst
6.1 Introduction 126
6.2 Dilutable beverages 127
6.2.1 Overview 127
6.2.2 Nomenclature 127
6.2.3 Ingredients 128
6.2.4 Manufacturing operations 137
6.2.5 Filling and packaging 139
6.2.6 Product range 140
6.3 Ready-to-drink non-carbonated products 140
6.3.1 Overview 140
6.3.2 Formulations 140
6.3.3 Special problems 140
6.3.4 Manufacturing and packing 141
6.3.5 Packaging types 142
6.4 Fruit juices and nectars 142
6.4.1 Processing 142
6.4.2 Packaging 144
Further reading 145
7 Carbonated beverages 146
D. Steen
7.1 Introduction 146
7.2 Carbon dioxide 147
7.3 Carbon dioxide production 148
7.3.1 Fermentation 148
7.3.2 Direct combustion 148
7.3.3 Quality standards 149
7.3.4 Delivery to the customer 149
7.3.5 Precautions 150
7.4 Carbonation 152
7.4.1 Basic considerations 152
7.4.2 Carbonation measurement 154
7.5 Syrup preparation 156
7.6 De-aeration 157
7.7 Carbonators 158
7.8 Filling principles 160
7.8.1 Gravity filler 161
7.8.2 Counter-pressure filler 163
7.8.3 Other filler types 167
7.8.4 Clean-in-place systems 169
7.9 Process control 171
7.10 Future trends 172
Further reading 173
8 Processing and packaging 174
R.A.W. Lea
8.1 Introduction 174
8.2 Juice extraction 174
8.3 Blending 175
8.3.1 Batch blending 176
8.3.2 Flip-flop blending 176
8.3.3 Continuous blending 176
8.4 Processing 177
8.4.1 Flash pasteurisation 177
8.4.2 Hot filling 178
8.4.3 In-pack pasteurisation 179
8.4.4 Aseptic filling 179
8.4.5 Chilled distribution 181
8.4.6 Summary 181
8.5 Control of process plant 181
8.6 Factory layout and operation 182
8.7 Hazard Analysis Critical Control Points 186
8.8 Good manufacturing practice 186
8.9 Cleaning in place 187
8.10 Packaging 188
8.11 Conclusion 191
9 Packaging materials 192
D. Rose
9.1 Introduction 192
9.2 Commercial and technical considerations 193
9.2.1 General considerations 193
9.2.2 Packaging materials 195
9.3 Processing 197
9.3.1 Cold-filling 197
9.3.2 In-pack pasteurising 197
9.3.3 Hot-filling 198
9.3.4 Aseptic filling of bottles 198
9.3.5 Liquid nitrogen injection 202
9.4 Bottles 202
9.4.1 Glass 202
9.4.2 Polyethylene terephthalate 203
9.4.3 High-density polyethylene 207
9.4.4 Polypropylene 207
9.4.5 Polyvinyl chloride 207
9.4.6 Plastic properties 208
9.5 Closures 209
9.5.1 Metal roll-on or roll-on pilfer-proof closures 209
9.5.2 Vacuum seal closures 210
9.5.3 Plastic closures 211
9.5.4 Crown corks 213
9.6 Cans 213
9.6.1 Metal bottles 218
9.6.2 Plastic cans 218
9.7 Cartons 218
9.8 Flexible pouches 221
9.9 Multipacks 222
9.10 Secondary packaging 223
9.11 Pack decoration 224
9.12 Environmental considerations 225
9.13 Conclusions 228
Acknowledgements 230
10 Analysis of soft drinks and fruit juices 231
D.A. Hammond
10.1 Introduction 231
10.2 Laboratory accreditation 234
10.3 Sensory evaluation 236
10.4 Water 237
10.5 Sweeteners 239
10.5.1 Analysis of natural sweeteners 240
10.5.2 Analysis of high-intensity sweeteners 245
10.6 Preservatives 249
10.6.1 Benzoic and sorbic acids 249
10.6.2 Sulphur dioxide 251
10.6.3 Dimethyldicarbonate 252
10.7 Acidulants 252
10.8 Carbonation 256
10.9 Miscellaneous additives 257
10.9.1 Caffeine 257
10.9.2 Quinine 258
10.9.3 Other additives 258
10.9.4 Fibre analysis 259
10.9.5 Herbal drinks 260
10.9.6 Osmolality 261
10.10 Analysis of colours used in soft drinks 261
10.10.1 Assessment of colour 263
10.10.2 Synthetic colours 265
10.10.3 Natural pigments 267
10.11 Vitamin analysis in soft drinks systems 272
10.11.1 Fat-soluble vitamins 274
10.11.2 Vitamin B class 274
10.11.3 Vitamin C 275
10.11.4 Vitamin analysis using immunological procedures 275
10.12 Methods used to detect juice adulteration 276
10.13 Methods used to assess the juice or fruit content of soft drinks 280
10.14 Conclusions 282
References 283
11 Microbiology of soft drinks and fruit juices 290
P. Wareing
11.1 Introduction 290
11.2 Composition of soft drinks and fruit juices in relation to spoilage 291
11.3 Background microbiology - spoilage 293
11.3.1 Sources 293
11.3.2 Yeasts 294
11.3.3 Bacteria 295
11.3.4 Moulds 297
11.4 Microbiological safety problems 299
11.4.1 Escherichia coli 299
11.4.2 Salmonella 299
11.5 Preservation and control measures 299
11.6 Sampling for microbial problems 301
11.7 Identification schemes and interpretation 301
11.7.1 Sample isolation 301
11.7.2 Non-molecular methods 302
11.7.3 Molecular identification 302
11.8 Brief spoilage case studies 303
11.9 Conclusions 304
References 306
Further reading 309
12 Functional drinks containing herbal extracts 310
E.F. Shaw and S. Charters
12.1 History 310
12.2 The extraction process 313
12.2.1 Extraction heritage 314
12.3 An extraction operation 320
12.3.1 Raw materials 321
12.3.2 Extraction 323
12.3.3 Organic extracts 329
12.3.4 Extract costs 329
12.4 Extract characteristics and their problems 331
12.4.1 Specifications 331
12.4.2 Stability 331
12.4.3 Hazing 332
12.4.4 Availability 333
12.5 Incorporation of extracts in beverages 333
12.5.1 Fruit juice-based and fruit-flavoured drinks 333
12.5.2 Mineral-water based and flavoured water drinks 334
12.5.3 Carbonated and dilutable drinks 334
12.5.4 Energy and sports drinks 334
12.5.5 Regulatory issues 335
12.6 Some commonly used herbs 337
References 354
13 Miscellaneous topics 356
P.R. Ashurst and Q. Palmer
13.1 Introduction 356
13.2 Nutrition 356
13.2.1 Nutritional components 357
13.2.2 Calculation and declaration of nutrition information 360
13.3 Sports drinks 363
13.3.1 Definition and purpose 363
13.3.2 Physiological needs 363
13.3.3 The absorption of drinks 365
13.3.4 Formulation 366
13.4 Niche drinks 369
13.4.1 Alcoholic-type drinks 369
13.4.2 Energy drinks 370
13.4.3 Functional drinks or nutraceuticals 371
13.4.4 Powder drinks 372
13.5 Dispensed soft drinks and juices 372
13.5.1 Introduction 372
13.5.2 Pre-mix and post-mix compared 373
13.5.3 Equipment 373
13.5.4 Outlets 375
13.5.5 Hygiene 375
13.5.6 Post-mix syrup formulation 376
13.5.7 Post-mix syrup packaging 377
13.6 Ingredient specifications 378
13.6.1 Why have specifications? 378
13.6.2 What a specification should include 378
13.6.3 Preparation of a specification 378
13.6.4 Supplier performance 379
13.7 Complaints and enquiries 380
13.7.1 Complaints 380
13.7.2 Enquiries 382
13.8 Health issues 383
13.8.1 Soft drinks and dental damage 383
13.8.2 Effect of colourings and preservatives 386
13.8.3 Obesity 387
13.9 Alternative processing methods 388
13.9.1 Microwave pasteurisation technology 388
13.9.2 High-pressure processing 393
13.9.3 Irradiation 395
References 396
Index 398
CHAPTER 1
Introduction
Philip R. Ashurst
Dr. P R Ashurst and Associates, Ludlow, UK
1.1 Overview
Fruit juices and soft drinks are available in essentially the same form almost anywhere in the world. From polar bases to the tropics, and from the largest developed nations to small and less developed countries, soft drinks and fruit juices are available in bottles, cans, laminated paper packs, pouches, cups and almost every other form of packaging known.
This chapter outlines what soft drinks are, describes the various types of products available and sets the scene for later chapters, which deal with the more specialised aspects of the chemistry and technology of these products.
1.2 Soft drinks
What are soft drinks? There is no single definition available, but it is generally accepted that they are sweetened, water-based beverages, usually with a balancing acidity. They are flavoured by the use of natural or artificial materials, are frequently coloured, and often contain an amount of fruit juice, fruit pulp or other natural ingredients. The predominant ingredient is water - often ignored and frequently maligned - and it should be considered that the primary function of soft drinks is hydration. The sweetness and other characteristics enhance the enjoyment of consumption and make the products more appealing to consumers. They are, in some respects, secondary, and yet have importance in the provision of energy and some of the minor essential nutrients needed to meet daily requirements.
It is generally accepted that the description of soft drinks excludes tea, coffee, dairy-based beverages and, until recently, alcohol. However, in many countries, the production of 'soft' drinks containing alcohol is growing. Many see this as an undesirable trend because, traditionally, the taste of alcoholic beverages has been associated with adulthood. The blurring of the edges between the markets and tastes for alcoholic drinks and soft drinks appears to facilitate an easy transition for children and young people to the consumption of alcohol. It should be noted that, in many soft drinks, small amounts of alcohol (less than 0.5% alcohol by volume (ABV)) may be present as a consequence of alcohol being used as a solvent for many flavourings. Small amounts of alcohol may also be present in fruit juices.
There are two basic types of soft drinks: the so-called ready-to-drink (RTD) products that dominate the world market and the concentrated, or dilute-to-taste, products that are still important in some markets. These include syrups and so-called squashes and cordials.
Whether RTD or dilutable, soft drinks characteristically contain water, a sweetener (usually a carbohydrate, although artificial sweeteners are increasingly important), an acid (citric or malic and phosphoric in colas are the most common), flavouring, colouring and preservatives. There is a large range of additional ingredients that can be used for various effects.
1.2.1 Ready-to-drink products
This sector accounts for the largest volume of soft drinks production, and is divided into products that are carbonated - that is, they contain carbon dioxide - and those that are not. Carbonated RTD soft drinks dominate the world market, and detailed consumption trends are discussed in Chapter 2 of this volume.
The market for carbonated soft drinks is dominated by two giant brands of cola drinks that, together with their associated brand names, account for just over half the world's consumption of such products.
Non-carbonated RTD beverages have shown some considerable growth in recent years, mainly because of the availability of aseptic packaging forms. Non-carbonated drinks that rely on chemical preservation, or hot-pack/in-pack pasteurisation, often suffer from a number of potential problems, including rapid deterioration of flavour and colour.
1.2.2 Concentrated soft drinks
Concentrated soft drinks became very important during the Second World War, and in the early years following that conflict. Many were based on concentrated orange juice, which was widely available as a nutritional supplement in the United Kingdom, packed in flat-walled medicine bottles.
The main markets for concentrated soft drinks developed mainly in the United Kingdom and its former empire. The products became universally known as 'squashes' or 'cordials', and became enshrined as such in UK food legislation in the 1960s.
Another very important development was the production of citrus comminutes. These were produced by mixing together, in appropriate proportions, the juice, peel components and essential oils of citrus fruits, and comminuting the mixture in a suitable mill. The resulting product delivered a more intense flavour and cloud than could be obtained from juice alone, and allowed the creation of 'whole fruit drinks', which have dominated the concentrates market in the United Kingdom over the past 40-50 years.
1.2.3 Legislation
It is not the intention of this chapter to cover legislation affecting soft drinks in any detail - not least, because it varies from country to country, and there is often a continuous variation of legislation within countries.
Legislation is, however, important from an historical perspective. For example, in the United Kingdom, the Soft Drinks Regulations 1964 (as amended) codified the products according to the way in which the industry was then organised, and set into law definitions not only of 'soft drinks', but also of many different product types, such as crushes, squashes and cordials. These names subsequently became generic household names in the United Kingdom and in many parts of the English-speaking world.
The above regulations were probably among the most proscriptive compositional statutes that existed for any food products in the United Kingdom, and for beverages anywhere in the world. As well as defining soft drinks, they laid down the requirement for minimum levels of sugars in certain product types, the maximum levels of saccharin (the only artificial sweetener then permitted) and the minimum levels of comminuted fruit and fruit juices that defined the best-known product categories. These regulations were eventually revoked in 1995.
The current trend is to move away from compositional legislation, to a much freer approach in which carbohydrates and other nutritional components can be used at will, and additives are taken from 'positive' lists of functional components. Other ingredients are frequently controlled by negative usage (i.e. they must not be present, or must not exceed closely defined limits).
This move to remove controls on formulations is now backed by informed labelling that contains increasing amounts of information for the consumer. This approach is now used widely throughout the world, with only relatively minor variations from country to country.
At the time of writing, the relevant European Union regulations (EU 1169/2011) require that a food which includes fruit juices and soft drinks must be labelled, and that labels must contain the following information:
- the name of the food;
- the list of ingredients;
- any ingredient or processing aid listed in Annex II (of the regulations), or derived from a substance or product listed in Annex II causing allergies or intolerances that is used in the manufacture or preparation of the food and is still present in the finished product, even if in an altered form;
- the quantity of certain ingredients or categories of ingredients (see below);
- the net quantity of the food;
- the date of minimum durability or the use-by date;
- any special storage conditions and or conditions of use;
- the name or business name and address of the food business referred to in Article 8(1);
- the country of origin or place of provenance, where provided for in Article 26;
- instructions for use where it would be difficult to make use of the food without such information;
- In beverages containing more than 1.2% of alcohol by volume of alcohol, the actual alcoholic strength by volume;
- a nutritional declaration.
It will be apparent that not all of the above will apply to fruit juices and soft drinks, but the declaration of the quantity of key ingredients (fruit or fruit juice in soft drinks) became law through earlier quantitative ingredient declaration regulations in Europe. Where artificial sweeteners and carbohydrates are used together, an appropriate statement is necessary. A warning about the product being a source of phenylalanine must be incorporated when aspartame is used as a sweetener.
Other additional regulations may also apply, and the above information should only be considered as a general guide. There is a wealth of additional information on this topic available on the internet. Readers requiring more specific information should consult appropriate authorities.
Because, in most countries, legislation is a rapidly changing sphere, it is essential for those formulating, producing and marketing soft drinks to update themselves regularly as regards the legislation of consumer countries, and to ensure label compliance.
1.2.4 Product types
1.2.4.1 Ready-to-drink products
Historically, soft drinks were refreshing beverages that copied or extended fruit juices. Fruit juices...
