Chemistry and Technology of Soft Drinks and Fruit Juices

Dr Philip R. Ashurst, Ashurst and Associates, Consulting Chemists to the Food Industry, Ludlow, UK.

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