Sensory Discrimination Tests and Measurements: Sensometrics in Sensory Evaluation

Sensory testing and measurement are the main functions of sensory analysis. In recent years, the sensory and consumer field has evolved to include both difference testing and similarity testing, and new sensory discrimination methods such as the tetrads have received more attention in the literature.

This second edition of Sensory Discrimination Tests and Measurements is updated throughout and
responds to these changes. It includes:

A wide range of sensory measurements:

o measurements of sensory effect (d , R–index, and Gini–index);

o measurements of the performance of a trained sensory panel (intraclass correlation coefficients and Cronbach s coefficient alpha);

o measurements of the relative importance of correlated sensory and consumer attributes (drivers of consumer liking or purchase intent);

o measurements of consumer emotions and psychographics;

o measurements of time–intensity;

o measurements of sensory thresholds;

o measurements of sensory risk with negative sensory effects (benchmark dose (BMD) methodology);

o measurements of sensory shelf life (SSL).

A balanced introduction of sensory discrimination tests, including difference tests and similarity tests.

A Bayesian approach to sensory discrimination tests.

Modified and multiple–sample discrimination tests.

Replicated discrimination tests using the beta–binomial (BB), corrected beta–binomial (CBB), and Dirichlet–multinomial (DM) models.

Sensory discrimination methods including the tetrads and the M + N .

R and S–Plus codes for all the measurements and tests introduced in the book.

Mainly intended for researchers and practitioners in the sensory and consumer field, Sensory Discrimination Tests and Measurements is a useful reference for modern sensory analysis and consumer research, especially for sensometrics.

Preface xiii

Acknowledgements xv

About the companion website xvii

1 Introduction 1

2 Measurements of sensory difference/similarity: Thurstonian discriminal distance 8

3 Measurements of sensory difference/similarity: area under ROC curve in Signal Detection Theory 42

4 Difference testing 60

5 Similarity (equivalence) testing 98

6 Bayesian approach to discrimination tests 139

7 Modified discrimination tests 162

8 Multiple–sample discrimination tests 202

9 Replicated discrimination tests: beta–binomial model 255

10 Replicated discrimination tests: corrected beta–binomial model 283

11 Replicated discrimination tests: Dirichlet multinomial (DM) model 301

12 Measurements of sensory thresholds 329

13 Measurements of sensory risk with negative sensory effects 345

14 Measurements of time intensity 365

15 Measurements of sensory shelf life 398

16 Measurements of the performance of a trained sensory panel and panelists 412

17 Measurements of consumer emotions and psychographics 444

18 Measurements of the relative importance of attributes 463

Appendix A List of R/S–Plus codes, data files, and packages used in the book 486

References 489

Author Index 517

Subject Index 525

Jian Bi is a consultant in sensometrics in the food and consumer product industries. From 1996 to 2000, he served as a Senior Statistician in the Institute for Perception in Richmond, VA, USA. Since 2000, he has, as an independent consultant, provided statistical consulting service and data analysis in sensory and consumer research for multiple companies, including Amway, Wrigley, Campbell Soup Company, Heinz, Kraft Foods, PepsiCo. Asia, and Mondelçz. He is the author or co–author of two books and more than 60 papers.