Statistical methods for food science : introductory procedures for the food practitioner

326 Pages·2013·4.04 MB·English

by  John A Bower, (Lecturer in food science)

Statistical Methods for Food Science
To Jonathan and Cassandra
and to Pushka-Latitia with love
“Everything is on a scale . . .”
Statistical Methods for Food Science
Introductory procedures for the food practitioner
Second Edition
John A. Bower
Former Lecturer and Course Leader (BSc Food Studies)
Queen Margaret University, Edinburgh, UK
This edition first published 2013 ⃝C 2013, 2009 by John Wiley & Sons, Ltd.
Wiley Blackwell is an imprint of John Wiley & Sons, formed by the merger of Wiley’s global
Scientific, Technical and Medical business with Blackwell Publishing.
Registered office: John Wiley & Sons, Ltd, The Atrium, Southern Gate, Chichester,
West Sussex, PO19 8SQ, UK
Editorial offices: 9600 Garsington Road, Oxford, OX4 2DQ, UK
The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, UK
111 River Street, Hoboken, NJ 07030-5774, USA
For details of our global editorial offices, for customer services and for information about how
to apply for permission to reuse the copyright material in this book please see our website at
www.wiley.com/wiley-blackwell.
The right of the author to be identified as the author of this work has been asserted in
accordance with the UK Copyright, Designs and Patents Act 1988.
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system,
or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording
or otherwise, except as permitted by the UK Copyright, Designs and Patents Act 1988, without
the prior permission of the publisher.
Designations used by companies to distinguish their products are often claimed as trademarks.
All brand names and product names used in this book are trade names, service marks,
trademarks or registered trademarks of their respective owners. The publisher is not associated
with any product or vendor mentioned in this book.
Limit of Liability/Disclaimer of Warranty: While the publisher and author(s) have used their
best efforts in preparing this book, they make no representations or warranties with respect to
the accuracy or completeness of the contents of this book and specifically disclaim any implied
warranties of merchantability or fitness for a particular purpose. It is sold on the understanding
that the publisher is not engaged in rendering professional services and neither the publisher
nor the author shall be liable for damages arising herefrom. If professional advice or other
expert assistance is required, the services of a competent professional should be sought.
Library of Congress Cataloging-in-Publication Data
Bower, John A. (Lecturer in food science)
Statistical methods for food science : introductory procedures for the food practitioner /
John A. Bower, former lecturer and Course Leader (BSc Food Studies) Queen Margaret
University, Edinburgh, UK. – Second edition.
pages cm
Includes bibliographical references and index.
ISBN 978-1-118-54164-7 (softback : alk. paper) – ISBN 978-1-118-54159-3 – ISBN
978-1-118-54160-9 (epdf) – ISBN 978-1-118-54161-6 (emobi) – ISBN 978-1-118-54162-3
(epub) 1. Food–Research–Statistical methods. I. Title.
TX367.B688 2013
664.0072–dc23
2013001794
A catalogue record for this book is available from the British Library.
Wiley also publishes its books in a variety of electronic formats. Some content that appears in
print may not be available in electronic books.
Cover images made up of a montage of figures from the book.
Cover design by hisandhersdesign.co.uk
⃝R
Set in 10/13pt Times New Roman by Aptara Inc., New Delhi, India
1 2013
Contents
Preface ix
About the companion website xi
Acknowledgements xiii
Part I Introduction and basics
Chapter 1 Basics and terminology 3
1.1 Introduction 3
1.2 What the book will cover 4
1.3 The importance of statistics 6
1.4 Applications of statistical procedures in food science 6
1.5 Focus and terminology 9
References 12
Software sources and links 13
Chapter 2 The nature of data and their collection 15
2.1 Introduction 15
2.2 The nature of data 15
2.3 Collection of data and sampling 26
2.4 Populations 36
References 42
Chapter 3 Descriptive statistics 44
3.1 Introduction 44
3.2 Tabular and graphical displays 45
3.3 Descriptive statistic measures 59
3.4 Measurement uncertainty 69
3.5 Determination of population nature and variance homogeneity 86
References 89
Chapter 4 Analysis of differences – significance testing 91
4.1 Introduction 91
4.2 Significance (hypothesis) testing 92
4.3 Assumptions of significance tests 102
4.4 Stages in a significance test 103
4.5 Selection of significance tests 108
4.6 Parametric or non-parametric tests 112
References 113
vi Contents
Chapter 5 Types of significance test 114
5.1 Introduction 114
5.2 General points 114
5.3 Significance tests for nominal data (non-parametric) 115
5.4 Significance tests for ordinal data (non-parametric) 122
5.5 Significance tests for interval and ratio data (parametric) 129
References 139
Chapter 6 Association, correlation and regression 141
6.1 Introduction 141
6.2 Association 142
6.3 Correlation 144
6.4 Regression 149
References 153
Chapter 7 Experimental design 155
7.1 Introduction 155
7.2 Terminology and general procedure 155
7.3 Sources of experimental error and its reduction 159
7.4 Types of design 164
7.5 Analysis methods and issues 174
7.6 Applicability of designs 176
References 176
Part II Applications
Chapter 8 Sensory and consumer data 181
8.1 Introduction 181
8.2 The quality and nature of sensory and consumer data 181
8.3 Experimental design issues 183
8.4 Consumer data (sensory and survey) 183
8.5 Trained panel sensory data 199
8.6 Analysis of relationships 216
References 216
Chapter 9 Instrumental data 219
9.1 Introduction 219
9.2 Quality and nature of instrumental data 219
9.3 Sampling and replication 222
9.4 Experimental design issues 224
9.5 Statistical analysis of instrumental data 226
9.6 Chemical analysis applications 228
9.7 Analysis of relationships 244
References 244
Contents vii
Chapter 10 Food product formulation 246
10.1 Introduction 246
10.2 Design application in food product development 246
10.3 Single ingredient effects 248
10.4 Two or more ingredients 252
10.5 Screening of many ingredients 257
10.6 Formulation by constraints 263
References 269
Chapter 11 Statistical quality control 271
11.1 Introduction 271
11.2 Types of statistical quality control 272
11.3 Sampling procedures 273
11.4 Control charts 274
11.5 Acceptance sampling 288
References 292
Chapter 12 Multivariate applications 293
12.1 Introduction 293
12.2 Multivariate methods and their characteristics 293
12.3 Multivariate modes 294
12.4 Relationship of consumer preference with sensory measures 310
References 311
Index 313
Preface
The recording and analysis of food data are becoming increasingly sophisticated.
Consequently, the practicing food scientist in industry or at study faces the task
of using and understanding statistical methods. Unfortunately, statistics is often
viewed as a difficult subject and tends to be avoided because of complexity and lack
of specific application to the food field. While this situation is changing and there
is much material on multivariate applications for the more advanced reader, a case
exists for a univariate approach for the non-statistician. That is the intent of this
book. It provides food scientists, technologists and other food practitioners with a
source text on accessible statistical procedures. Material for students and workers
in the food laboratory is included, covering the food analyst, the sensory scientist
and the product developer. Others who work in food-related disciplines involving
consumer survey investigations will also find many sections of use. Emphasis is
on a ‘hands-on’ approach with worked examples using computer software with
the minimum of mathematical formulae.
For the second edition, the content has been revised, some errors corrected and
additional information and detail given at various points. The main thrust of the
analyses, Excel use, has been updated for Excel 2010 format, whilst retaining the
instructions for Excel 2003. This update includes some of the amended formulae as
well as the new style of menu interaction when using the calculation and charting
facilities.
About the companion website
This book is accompanied by a companion website:
www.wiley.com/go/bower/statistical
Excel spreadsheet files with data are available on the website in both formats (2010
and 2003), so that readers can perform the calculations in the text or use new data
for their own examples and exercises.
Acknowledgements
I thank all students of food at Queen Margaret University, Edinburgh (1985–
2007), for their enthusiasm and contribution to experimentation in the study of
food science and consumer studies. Also, thanks are due to my colleagues in the
Department of Consumer Studies, in particular Dr. Monika Schro¨der for many
stimulating conversations and for her help with reading and editing of early drafts.
The publishers and author thank the following for permission to include output
material:
SPSS Software (IBM⃝R /SPSS⃝R )1 graphs and tables by International Business
Machines. Corporation (pp. 193, 295, 299, 300, 301, 303, 307 and 308).
Excel spreadsheet tables and graphs by Microsoft⃝R Corp.
Design-Expert(R) software output by Stat-Ease, Inc.
Examples of Minitab⃝R Statistical Software output by Minitab Inc.: Portions of
information contained in this publication/book are printed with permission of
Minitab Inc. All material remains the exclusive property and copyright of Minitab
Inc. All rights reserved.
Trademark notice
The following are trademarks or registered trademarks of their respective compa-
nies:
Excel is a trademark of Microsoft⃝R Corporation.
Minitab (Minitab⃝R Statistical SoftwareTM) is a trademark of Minitab Inc.
Design-Expert(R) software is a trademark of Stat-Ease Inc., Minneapolis, MN.
SPSS is a trademark or registered trademark of International Business Machines
Corp., registered in many jurisdictions worldwide.
MegaStat is a trademark of McGraw-Hill/Irwin, McGraw-Hill Companies Inc.
Minitab⃝R and all other trademarks and logos for the Company’s products and ser-
vices are the exclusive property of Minitab Inc. All other marks referenced remain
the property of their respective owners. See minitab.com for more information.
1 SPSS Inc. was acquired by IBM in October 2009.