Post-harvest Technologies for Fruits and Vegetables

326 Pages·2015·21.585 MB·English

by  Hosahalli S. Ramaswamy

POST-HARVEST TECHNOLOGIES
OF FRUITS & VEGETABLES
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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.
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Lanc ast er, Penns ylv an ia 17602 U.S.A.
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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 
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