Principes and Practices of Small- and Medium-Scale Fruit Juice Processing
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FAO AGRICULTURAL SERVICES BULLETIN 146 Rome, 2001 FOREWORD This bulletin presents both theoretical and practical information on the processing of fruit and vegetable juices, thus offering the reader both the principles and practices of small and medium-scale fruit juice processing. While large-scale juice processing is the subject of many textbooks and other printed or electronic publications, small-scale operations generally receive very little attention. The purpose of this publication is to fill the gap in information available to professionals as well as private entrepreneurs, mainly in developing countries. It is the medium and small-scale agro-industries that more appropriately fill the needs and capabilities of these countries, considering the available volume of production and the capacity of local markets to absorb products. The bulletin is divided into two parts. The first gives the general principles of fruit and vegetable juice processing. It starts with a general history and background of juice production and continues through fruit composition, juice grades, harvesting and post-harvest handling of the fruit, and on to the general principles of juice manufacturing and presentation. It also covers the processing related products such as jams, jellies, pectin, essential oil etc. The second part describes in detail the processing of specific juices as well as the major by-products. Citrus juice, especially orange juice, receives particular attention. Specific chapters are dedicated to grape, apple, stone fruits as well as a long list of tropical fruits. The methods of processing of major vegetable juices are also covered. Finally, the publication presents a list of printed as well as electronic sources of information for further reading. FAO will be pleased to receive comments and provide any additional information required. Please address enquiries to: The Chief Agro-Industries and Post-Harvest Management Service Agricultural Services Division FAO of the U.N. Via delle Terme di Caracalla 00100 Rome ITALY iii TABLE OF CONTENTS PAGE FOREWORD iii PART 1 GENERAL PRINCIPLES 1 CHAPTER 1. INTRODUCTION AND HISTORICAL BACKGROUND 3 1.1 Purpose of publication 3 1.2 Historical background 5 1.3 The value of juice 6 CHAPTER 2. DEFINING JUICES 11 2.1 Some definitions 11 2.2 Juice criteria 12 CHAPTER 3. FRUIT MORPHOLOGY AND COMPOSITION 17 3.1 Distinctions 17 3.2 Fruit/juice general composition 19 3.3 Phytochemicals 20 CHAPTER 4. JUICE SAFETY, GRADES AND STANDARDS 23 4.1 Safety, safety and safety 23 4.2 Quality 25 4.3 Regulatory concerns 26 CHAPTER 5. RAW MATERIAL FOR JUICE 29 5.1 Initial considerations 29 5.1.1 Fruit cultivar 29 5.1.2 Cultivation practices 30 5.1.3 Harvest season and maturity 32 5.1.4 Harvest and post-harvest handling 34 CHAPTER 6. GENERAL JUICE MANUFACTURE PRINCIPLES 37 6.1 Unit operations applied to juice 37 6.1.1 Pre-process storage 39 6.1.2 Cleaning, sorting and inspection 40 6.1.3 Crushing and juicing 43 6.1.4 Pressing 49 6.1.5 Juice clarification 53 6.1.6 Filtration 56 6.1.7 Deaeration 57 6.1.8 A word of caution regarding processing systems 57 v PAGE CHAPTER 7. GENERAL JUICE PROCESSING PRINCIPLES 59 7.1 Juice spoilage 59 CHAPTER 8. JUICE STABILIZATION AND PRESERVATION 63 8.1 Some definitions 63 8.1.1 Refrigeration + sanitation 63 8.1.2 Freezing 64 8.1.3 Combined methods 64 8.1.4 Competitive inhibition 66 8.2 Thermal processing 67 8.2.1 Canning 68 8.2.2 Hot fill 69 8.2.3 Aseptic processing 70 8.3 Non thermal and other methods 71 8.3.1 Sterile filtration 71 8.3.2 Chemical preservatives 72 8.3.3 Newer methods 74 8.4 Concentration 75 8.5 Jelly and jam manufacture 78 8.6 Wine 79 8.7 Water removal and water activity 82 8.8 Dehydration 83 8.9 Vacuum drying 84 8.10 Juice packaging systems 87 8.10.1 Storage requirements 91 8.10.2 Active packaging 91 8.10.3 Product identification 92 8.10.4 Bulk storage 92 CHAPTER 9. JUICE AND BEVERAGE BLENDS 95 9.1 Rationale 95 9.1.1 Blending strategies 95 CHAPTER 10. COMPLEMENTARY PRODUCTS AND BY-PRODUCTS 101 10.1 Trends 101 10.1.1 Pectin 101 10.1.2 Essential oils and essences 101 10.1.3 Pigments 101 vi PAGE 10.2 Phytochemicals 103 PART 2 SPECIFIC JUICE PRODUCTS 105 CHAPTER 11. PRACTICAL ASPECTS OF CITRUS JUICE PROCESSING 107 11.1 What is citrus and where is it grown? 107 11.2 Nutritional benefits from consuming citrus 111 11.2.1 Sport or isotonnesic beverages 111 11.2.2 Energy beverages 112 11.2.3 Nutraceutical beverages 112 11.2.4 Herbal beverages 112 11.2.5 Smart beverages 112 11.2.6 Fun beverages 113 11.3 Economically feasible by-products from citrus and an idea of volumes 113 11.3.1 Pectin 114 11.3.2 Pectin pomace and dietary fibre 114 11.3.3 Dried citrus peel 115 11.3.4 Pulp wash 118 11.3.5 Juice sacs and whole juice vesicles 118 11.3.6 Beverage bases and clouding agents 118 11.3.7 Healthful, nutraceutical citrus beverages 118 11.3.8 Fractionated citrus oils and D-limonene 119 11.3.9 Citrus molasses and beverage alcohol base 119 11.3.10 Flavonoids and limonin 119 11.3.11 Conclusions 119 11.4 Overview of large scale citrus processing operation 119 11.4.1 Harvesting and transporting oranges into the processing plant 120 11.4.2 Citrus juice extraction systems 122 11.4.3 Manufacture of peel oil 124 11.4.4 Evaporation, concentration of the juice, storage and transportation 125 11.4.5 Saving money by manufacturing 72°Brix concentrate 126 11.5 Principle pieces of citrus extraction equipment for use at an appropriate scale 126 11.5.1 Small village-scale harvesting 126 11.5.2 Washing and storing fruit 126 11.5.3 Small-scale citrus 127 11.5.4 Small-scale citrus extraction 127 vii PAGE 11.5.5 Small-scale citrus juice pasteurization 128 11.6 Overview of small-scale fruit processing equipment with references on how to make equipment 131 11.7 Sanitation and good manufacturing practices 131 11.7.1 International 131 11.7.2 National and local regulations 131 11.8 Processing citrus other than oranges 132 11.8.1 Tangerine 132 11.8.2 Grapefruit 132 11.8.3 Lemon and lime 132 11.8.4 Exotic fruits 133 11.8.5 Conclusion 133 CHAPTER 12. GRAPE JUICE 135 12.1 Importance 135 12.2 Grape juice composition 135 12.3 Pre-harvest factors influencing grape juice quality 136 12.3.1 Climate 136 12.3.2 Soil 137 12.3.3 Cultivar 137 12.3.4 Vineyard management 137 12.4 Harvest and post-harvest factors influencing grape juice quality 138 12.5 Juice production 138 12.5.1 Hot press 140 12.5.2 Cold press 141 12.6 Processing factors that influence quality 141 12.7 Grape juice concentrate 142 12.7.1 Rising film evaporator 143 12.7.2 Falling film evaporator 143 12.7.3 Plate evaporators 144 12.7.4 Centrifugal or conical evaporators 144 12.7.5 Freeze concentration 144 12.8 Grape spreads 144 12.8.1 Sweeteners 145 12.8.2 Acids 145 12.8.3 Buffer salts 146 viii PAGE 12.9 Pectins 146 12.9.1 Addition of pectin 147 12.9.2 Syneresis 147 12.9.3 Procedure 148 CHAPTER 13. TREE FRUIT: APPLE, PEAR, PEACH, APRICOT AND PLUMS 151 13.1 Raw material 13.2 Harvest 151 13.2.1 Time elapsed from full bloom to maturity 153 13.2.2 Starch/iodine test 153 13.2.3 Pressure test 153 13.2.4 Soluble solids 154 13.2.5 Ground colour change 155 13.2.6 Flesh colour change 155 13.2.7 Water core 156 13.2.8 Easy removal of fruit from spur 156 13.3 Storage 156 13.4 Storage facilities 156 13.4.1 Air-cooled storage 156 13.4.2 Mechanically refrigerated storage 157 13.5 Processing 157 13.6 Apple juice manufacture 158 13.6.1 Pre-juicing 159 13.6.2 Extraction 160 13.6.3 Unclarified juice 161 13.6.4 Enzyme treatment 162 13.6.5 Tannin and gelatin treatment 162 13.6.6 Heat clarification 163 13.6.7 Centrifuged apple juice 164 13.6.8 Bentonnesite fining 164 13.6.9 Filtration 164 13.7 Pasteurization 165 13.8 Concentration 166 13.9 Applesauce 166 13.10 Pears 166 ix PAGE 13.11 Peaches 167 13.12 Apricot 168 13.13 Plums and prunes 168 CHAPTER 14. BERRIES 171 14.1 Cranberry 171 14.2 Strawberry 172 14.3 Blueberry 175 14.4 Blackberry 175 14.5 Raspberry and other berries 175 14.6 Cherry 176 CHAPTER 15. TROPICAL FRUITS 177 15.1 Pineapple 178 15.2 Mango 180 15.3 Passion fruit 180 15.4 Guava 182 15.5 Papaya 182 15.6 Guanabana (Soursop) 183 15.7 Acerola 184 15.8 Naranjilla 185 15.9 Carambola 185 15.10 Lychee 185 15.11 Banana 185 15.12 Other fruits for juice 187 CHAPTER 16. VEGETABLE JUICES 189 16.1 Tomato juice 191 16.2 Carrot 193 16.3 Other juices 195 16.4 Non-fruit/vegetable juices 196 CHAPTER 17. COMPLEMENTARY/COMPETITIVE PRODUCTS 197 17.1 Jams, jellies and syrups 197 17.2 Smoothies 197 17.3 Dairy 197 17.4 Sports drinks 197 17.5 Herbals and teas 199 17.6 Competitive products 199 x PAGE CHAPTER 18.