Handbook of Indices of Food Quality and Authenticity (Woodhead Publishing Series in Food Science, Technology and Nutrition)

563 Pages·1997·29.13 MB·English

by  Rekha Singhal

Handbook of indices of
food quality and
authenticity
Rekha S Singhal
Pushpa R Kulkarni
Dinanath V Rege
WOODH E AD PUBLISHING LIMITED
Cambridge England
Published by Woodhead Publishing Limited
Abington Hall, Abington
Cambridge CB16AH, England
First published 1997 Woodhead Publishing Limited
0 1997, Woodhead Publishing Ltd
All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any
means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval
system, without permission in writing from the publisher.
While a great deal of care has been taken to provide accurate and current information, neither the author,
nor the publisher, nor anyone else associated with this publication, shall be liable for any loss, damage or
liability directly or indirectly caused or alleged to be caused by this book.
British Library Cataloguing in Publication Data
A catalogue record for this book is available from the British Library
ISBN 1 85573 299 8
Designed by Geoff Green (text) and The ColourStudio (cover)
Typeset by Textype Typesetters, Cambridge, England
Printed by T J International Ltd, Cornwall, England
Preface
Assessment of food quality has all along been in terms of wholesomeness, acceptability
and adulteration. Many ingenious approaches have been worked out and subjected to
comparative investigations. Their reproducibility, sensitivity, simplicity and feasibility
for routine application have been critically evaluated in collaborative studies and the
methods approved have been selected as official. Several of these methods have
withstood the test of time. The history of the Kjeldahl method for the determination
of nitrogen and proteins in foods is unique as it has survived over a hundred years.
During the recent past however several new challenges have been posed to the food
scientist and the food analyst. Factors such as identification of botanical source and of
geographical origin, the diverse and varying contaminations that enter through the
environment including agrochemical residues and radioactive isotopes, the discovery
of new health hazards, the manufacture and marketing of new formulations and blends,
the chemical, biochemical and biologically induced changes in composition, chemical
changes associated with processing including thermal, radiation, fermentation and
such other treatments all have come to the attention of food manufacturers as well as
-
the enlightened consumers who have become aware of the implications of many of
these factors in the success of the food processing operation, maintenance of quality
and uniformity of the product and above all the wholesomeness of the food articles that
reach the consumer. The traditional methodology for food analysis has begun to reveal
inadequacy in tackling these and other such problems that have arisen continually.
At the same time since the mid-1970s there has been brisk activity in biological
research from which novel analytical approaches have been emerging. The work on
chemotaxonomy that began in a faltering manner a few decades earlier, has gained
momentum and several new observations of far reaching importance to analysts have
emerged. New molecules in the plant kingdom have been discovered as antinutritional
or toxic phytoalexins, substances imparting resistance to pests. Many of these may be
species specific or even variety specific. Most notable, however, is knowledge of
molecular biology and genetics which has enabled the development of novel analytical
applications based on the unique properties of proteins and nucleic acids.
It is therefore considered opportune to survey these trends and highlight the novel
approaches that are opening up to the analyst and that are sure to help in solving the
new problems that the food scientist is likely to face in the future. Problems arising in
the area of major food commodities, the application of the new approaches and the
direction of future work are indicated. It is hoped that this discussion will be fruitful in
8 Handbook of indices of food quality and authenticity
inducing analytical researchers to reorient themselves to the new and varied
parameters of food quality that are gaining prominence.
This project would not have borne fruit had it not been for the active support and
encouragement from a number of individuals and organizations. The authors take
great pleasure in acknowledging Prof. M. M. Sharma, Director, Department of
Chemical Technology, University of Bombay (UDCT), Bombay, for the keen interest
he has taken in this project and the readiness with which he has provided
infrastructural facilities. Generous support from Dr. R. Rajgopal of M/S Colour
Publications Pvt. Ltd., Bombay, M/S Anchrom Enterprises TLC Specialists, M/S
-
AS Computech, colleagues and students is also gratefully acknowledged. The entire
library staff of the UDCT and the Central Food Technological Research Institute,
Mysore, deserves a special mention for their cooperation and assistance. We appreciate
greatly the silent support offered by our families.
R. S. SINGHAL
P. R. KULKARNI
D. V. REGE
Contents
Preface 7
Chapter 1 The Development of the Concept of Food Quality, Safety and Authenticity 9
1.1 Diversity of composition 10
1.2 Food contaminants 10
1.3 Food quality 11
1.4 Nutritive quality 12
1.5 Food safety 12
1.6 Natural toxicants 13
1.7 Problem of chemical residues 13
1.8 Problem of food adulteration 14
1.9 Changes associated with processing 14
1.10 Conservation of excess produce 15
1.11 Evolution of food legislation 16
1.12 Current methods of food analysis 17
1.13 New techniques for food analysis 19
1.14 Validation and approval of alternative methods of microbial analysis 29
1.15 Quality management systems 29
1.16 Clean food campaigns 30
1.17 Current issues in food regulations in the EU and USA 30
References 31
Chapter 2 Food Grains 35
2.1 Introduction 36
2.2 Contaminants in grains 38
2.3 Interspecies and intervarietal wheat admixtures 38
2.4 Intervarietal rice admixtures 42
2.5 Cereal/cereal and cereal/legume blends 44
2.6 Indices for processing quality of wheat and other grains 46
2.7 Indices for microbial quality of cereals and cereal-based products 58
2.8 Indices of insect infestation of grains 63
2.9 Detection of damaged grains in sound grains 67
2.10 Other grains 67
References 68
4 Handbook of indices of food quality and authenticity
Chapter 3 Fruit and Vegetable Products 77
3.1 Introduction 78
3.2 Quality indices of fruit and vegetable juices 80
3.3 Organic acids and other additives 84
3.4 Peel homogenates in citrus juices 88
3.5 Dilution of fruit juices with water 89
3.6 Juice blends 98
3.7 Maturity and ripeness indices of fruits and vegetables 108
3.8 Non-microbial methods for determining microbial quality 114
119
References
Chapter 4 Milk and Milk Products 131
4.1 Introduction 133
4.2 Milk of different origins 133
4.3 Whey or buttermilk in milk 143
4.4 Reconstituted milk 149
4.5 Adulteration in milk and other dairy products 151
4.6 Other fats in milk fat, butter or ghee 153
4.7 Dilution of milk with water 168
4.8 Indices of microbial quality of dairy products 177
4.9 Indices of aesthetic quality of dairy products 193
4.10 Qualityofcheese 194
References 195
Chapter 5 Meat. Fish and Poultry 209
5.1 Introduction 211
5.2 Identification of meat species 212
5.3 Freshness indicators 231
5.4 Eating quality of fleshy foods 253
5.5 Evaluation of the age of the animal carcass 259
5.6 Contaminants in flesh foods 260
5.7 Quality of comminuted meats 267
5.8 Meat additives and adulterants 268
5.9 Egg: quality criteria 271
References 278
Contents 5
Chapter 6 Edible Oils and Fats 300
6.1 Introduction 302
6.2 Indicators of storage changes 306
6.3 Indicators of quality of heated oils 309
6.4 Toxic contaminants and adulterants 311
6.5 Indices of admixtures, blends, contaminants and adulterants
-
one fat in another 320
6.6 Sensory quality of oils 345
References 347
Chapter 7 Honey: Quality Criteria 358
7.1 Introduction 3 59
7.2 Adulteration of honey 362
7.3 Honey obtained from sugar-fed bees 370
7.4 Identifying the botanical/geographical origin of authentic honey 371
7.5 Contaminants of honey 378
References 379
Chapter 8 Spices, Flavourants and Condiments 386
8.1 Introduction 387
8.2 Spices as flavourants 394
8.3 Essential oils 423
8.4 Adulteration of spice essential oils 426
8.5 Citrus essential oils 429
8.6 Vanilla extract 434
8.7 Mint flavours 437
8.8 Saffron 43 8
8.9 Almond oil 440
8.10 Oil of sassafras 441
8.11 Vinegar 442
8.12 Miscellaneous 446
References 447
Chapter 9 Tea, Coffee and Cocoa 457
9.1 Introduction 458
9.2 Tea 458
9.3 Coffee 467
9.4 Cocoa and cocoa products 476
References 483
6 Handbook of indices of food quality and authenticity
Chapter 10 Indicators of Processing of Foods 489
10.1 Introduction 49 1
10.2 Thermal processing 49 1
10.3 Indicators of processing quality of beans 505
10.4 Fresh versus frozen-thawed foods 507
10.5 Indicators of storage quality of foods 508
10.6 Indicators of irradiation of foods 510
References 526
Index 538
Chapter 1
The Development of the Concept of Food Qua
Safety and Authenticity
1.1 Diversity of composition
1.2 Food contaminants
1.3 Food quality
1.4 Nutritive quality
1.5 Food safety
1.6 Natural toxicants
1.7 Problem of chemical residues
1.8 Problem of food adulteration
1.9 Changes associated with processing
1 .I 0 Conservation of excess produce
1 .I 1 Evolution of food legislation
1. I2 Current methods of food analysis
1. I3 New techniques for food analysis
1.13.1 Enzymes as indicators of food quality
1. I32 Biosensors in food analysis
1.13.3 Immunochemical techniques
1.13.4 DNA probes
1.13.5 Polymerase chain reaction
1.13.6 Rapid methods for microbiological analysis of foods
1.13.7 Authentication of foods using isotopic methods
1.13.8 RSK values
1.13.9 Identification of fish species in seafoods
1.14 Validation and approval of alternative methods of microbial analysis of foods
1 .I 5 Quality management systems
1 .I6 Clean food campaigns
1 .I7 Current issues in food regulations in the EU and USA
References