Post-harvest Technologies for Fruits and Vegetables PDF
Preview Post-harvest Technologies for Fruits and Vegetables
POST-HARVEST TECHNOLOGIES OF FRUITS & VEGETABLES HOW TO ORDER THIS BOOK BY PHONE: 877-500-4337 or 717-290-1660, 9AM–5PM Eastern Time BY FAX: 717-509-6100 BY MAIL: Order Department DEStech Publications, Inc. 439 North Duke Street Lancaster, PA 17602, U.S.A. BY CREDIT CARD: American Express, VISA, MasterCard, Discover BY WWW SITE: http://www.destechpub.com Post-harvest Technologies of Fruits & Vegetables HOSAHALLI S. RAMASWAMY, PHD, FCSBE, FAFST (I) Professor Department of Food Science and Agricultural Chemistry McGill University DEStech Publications, Inc. Post-harvest Technologies of Fruits & Vegetables DEStech Publ ic at ions, Inc. 439 North Duke Street Lanc ast er, Penns ylv an ia 17602 U.S.A. Copyr ight © 2015 by DEStech Publ ic at ions, Inc. All rights res erved No part of this publ ic at ion may be rep rod uced, stored in a ret rieval syst em, or transm itt ed, in any form or by any means, elect ronic, mec hani c al, phot oc opyi ng, rec ordi ng, or othe rw ise, witho ut the prior writt en per miss ion of the publ isher. Printed in the United States of Ameri ca 10 9 8 7 6 5 4 3 2 1 Main ent ry und er tit le: Post-harvest Technologies of Fruits & Vegetables A DEStech Publ ic at ions book Bibl io gr ap hy: p. Inc ludes ind ex p. 311 Library of Congress Control Number: 2014940614 ISBN No. 978-1-932078-27-5 Contents Preface ix Acknowledgements xi 1. An Overview of Postharvest Losses and Causes . . . . 1 Introduction 1 Causes of Postharvest Losses 7 2. Classification of Fruits and Vegetables . . . . . . . . . . . 11 Definitions 11 Classification of Fruits and Vegetables 13 3. Structure of Fruits and Vegetables . . . . . . . . . . . . . . . 23 Introduction 23 Structure of a Plant Cell 23 Structure of Fruits and Vegetables 26 Texture of Fruits and Vegetables 31 Texture-Structure Relationships 35 4. Composition and Nutritional Qualities . . . . . . . . . . . . 37 Introduction 37 Water 39 Carbohydrates 40 Proteins 46 Fats and Oils 46 v vi Contents Organic Acids 50 Vitamins and Minerals 51 Pigments 53 Flavor Compounds 56 Anti-Nutritional Factors in Foods 57 5. Harvesting of Fruits and Vegetables . . . . . . . . . . . . . 59 Introduction 59 Hand Harvesting 59 Mechanized Harvesting 60 Elements of Harvesting: Hand/Mechanical 62 Important Field/Orchard-Considerations for Mechanized Harvest 62 Types of Mechanical Harvesters 64 Harvest Aids 64 Extent of Mechanization 65 6. Quality and Maturity Indices . . . . . . . . . . . . . . . . . . . . 71 Introduction 71 Factors Influencing Quality 75 7. Post Harvest Physiology of Fruits and Vegetables: Respiration . . . . . . . . . . . . . . . . . . . . . . . . 85 Introduction 85 Aerobic vs Anaerobic Respiration 86 Energy Currency—ATP 86 Aerobic Oxidation of Glucose 87 Biochemical Pathways 89 Anaerobic Respiration 93 Factors Influencing Respiration 94 Control Measures to Minimize Respiratory Losses 104 Typical Calculations Involving Respiration Problems 104 8. Post Harvest Physiology of Fruits and Vegetables: Transpiration . . . . . . . . . . . . . . . . . . . . . 107 Introduction 107 Degree of Cooling Achieved by Transpiration 107 Significance of Transpiration During Plant Growth 108 Transpiration Represents Economic Loss 108 Contents vii Transpiration Occurs through Specialized Tissues 109 Transpiration is a Diffusion Phenomenon 109 Partial Pressure, Saturated Water Vapor Pressure and Relative Humidity 110 Factors Influencing Transpiration 117 Methods of Controlling Transpiration Losses 119 Psychrometry 120 9. Cooling of Fruits and Vegetables . . . . . . . . . . . . . . . 127 Introduction 127 Modes of Heat Transfer 132 Cooling Rate 137 Cooling/Pre-cooling Methods 145 Principles of Refrigeration 154 10. Cold Storage Systems for Fruits and Vegetables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167 Introduction 167 Refrigeration Requirements 177 Ventilated Storage 183 Refrigerated (Regular Atmosphere, RA) Storage 184 Control Atmosphere (CA) Storage Systems 189 Ethylene in Post-Harvest Technology 194 Membrane System for CA/MA 196 Hypobaric System for CA/MA 205 11. Packaging of Fruits and Vegetables . . . . . . . . . . . . . 211 Introduction 211 Package as a Handling Unit 212 Protection from Physical and Mechanical Injuries 214 Protection from Moisture Loss 217 Providing a Sanitary Environment 218 Facilitating Important Treatments 219 Prevention of Pilferage 219 Improvement of Sales Promotion 220 Communication with Consumers 220 Promotion of Product Identification and Company Recognition 220 viii Contents Facilitation of Sales 221 Generation of Modified Atmosphere within the Package 221 Types of Containers 222 Types of Packaging Materials 223 Packaging Requirements for Fruits and Vegetables 230 Modified Atmosphere Packaging 231 12. Irradiation of Fruits and Vegetables . . . . . . . . . . . . . 241 Introduction 241 Historical Perspectives 243 Forms of Radiation 243 Characteristics of Ionizing Radiations 248 Sources of Ionizing Radiations 250 Units of Radiation 255 Radiation Dose 258 Food Irradiation Worldwide 264 Detection of Radiation 273 Regulatory Approval 273 Economic Aspects 279 The Future 280 13. Postharvest Pathology . . . . . . . . . . . . . . . . . . . . . . . . 281 Introduction 281 Common Diseases 282 Disease Development 285 Mechanism of Pathogen Entry 287 The Infection Process 287 Defense Mechanism 287 Growth Behavior of Bacteria and Fungi 288 Treatments for Pathogen Control 290 Pre-Harvest Control 293 14. Postharvest Treatments . . . . . . . . . . . . . . . . . . . . . . . 295 Insect Control 295 Chilling Injury 302 Freezing Injury 304 References and Reading Materials 307 Index 311 CHAPTER 1 An Overview of Postharvest Losses and Causes INTRODUCTION THE word “harvest” triggers many sensations among people in countries that depend on agricultural production. It is the beginning of realizing the gain from all the hard work that has been put in right from the time of planting, watching the crop grow and bear fruit. It is celebrated with fervor in many countries, certainly a time to enjoy the reaps of their bounties. It is a reverberating magic word which gives the farmer the gorgeous images of a golden field of wheat or paddy ready to be brought home. Imagine the orchards of full apple, orange and cherry trees, the fields displaying a multitude of vegetables or the vines of grapes sagging with fruit. But however natural or noble it may be when we harvest, the act isn’t all that beneficial for the crops going through the harvesting process. For the bulk of fruits and vegetables it is a painful act of separation from the mother plant. When we pluck the bunch of grapes, chop the head of cabbage, cut the hands of bananas, slash the trunk of sugar cane, pull the ears of corn, lift the roots of carrots, snap the vines of beans, how can that be beneficial? This means an abrupt termination of their life. In human law, such acts would sound grave and warrant a great many pun- ishments. However strange it may sound when we use the same words with produce, they characterize the various changes that the produce goes through during the postharvest period. Maybe for a few crops like wheat, rice and other staple food crops, it may not look that bad since they generally stay on the plant until their fruits become fully mature 1
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