ApPENDIX A

Some Useful Tables for Sensory Tests

The following tables were derived using the MINITAB statistical pack• age.

177 178 GUIDELINES FOR SENSORY ANALYSIS

Table A-1 The number of assessors in a paired comparison or duo-trio test required to give correct judgments, at three different significance lev- els (one-tailed test). Note: Not valid for preference.

Significance Level Number of Assessors 5% 1% 0.1% 7 7 7 8 7 8 9 8 9 10 9 10 10 11 9 10 11 12 10 11 12 13 10 12 13 14 11 12 13 15 12 13 14 16 12 14 15 17 13 14 16 18 13 15 16 19 14 15 17 20 15 16 18 21 15 17 18 22 16 17 19 23 16 18 20 24 17 19 20 25 18 19 21 26 18 20 22 27 19 20 22 28 19 21 23 29 20 22 24 30 20 22 24 31 21 23 25 32 22 24 26 33 22 24 26 34 23 25 27 35 23 25 27 36 24 26 28 37 24 26 29 38 25 27 29 39 26 28 30 40 26 28 30 41 27 29 31 42 27 29 32 43 28 30 32 44 28 31 33 45 29 31 34 50 32 34 37 Appendix A 179

Table A-2 The number of assessors in a triangle test required to give correct judgments, at three different significance levels.

Significance Level Number of Assessors 5% 1% 0.1% 7 5 6 7 8 6 7 8 9 6 7 8 10 7 8 9 11 7 8 10 12 8 9 10 13 8 9 11 14 9 10 11 15 9 10 12 16 9 11 12 17 10 11 13 18 10 12 13 19 11 12 14 20 11 13 14 21 12 13 15 22 12 14 15 23 12 14 16 24 13 15 16 25 13 15 17 26 14 15 17 27 14 16 18 28 15 16 18 29 15 17 19 30 15 17 19 31 16 18 20 32 16 18 20 33 17 18 21 34 17 19 21 35 17 19 22 36 18 20 22 37 18 20 22 38 19 21 23 39 19 21 23 40 19 21 24 41 20 22 24 42 20 22 25 43 20 23 25 44 21 23 26 45 21 24 26 50 23 26 28 ApPENDIX B

Glossary of Terms Used in Sensory Analysis

In most cases, contributors to Guidelines for Sensory Analysis in Product Development and Quality Control have used nomenclature as de• fined in the International Standard Sensory Analysis-Vocabulary (ISO 5492, 1992 (Elf».

Acceptability (noun) State of a product favourably received by a given individual or popUlation, in terms of its organoleptic attributes. Acid () (adj.) Describes the basic taste produced by dilute aqueous solutions of most acid substances (e.g., citric acid and tartaric acid). After-taste (noun) O1factory and/or gustatory sensation which occurs after the elimination of the product and which differs from the sensations per• ceived whilst the product was in the mouth. Appearance (noun) All the visible attributes of a substance or object.

Source: Extracts from ISO 5492: 1992 are reproduced with permission under license number PD\1999 0174. Complete copies ofthe standard can be obtained by post from BSI Customer Services, 389 Chiswick High Road, London, W4 4AL, or through national standards bodies.

181 182 GUIDELINES FOR SENSORY ANALYSIS

Assessor (sensory) (noun) Any person taking part in a sensory test. NOTE: A naive assessor is a person who does not meet any particular criterion. An initiated assessor is a person who has al• ready participated in a sensory test. Attribute (noun) Perceptible characteristic. Bias (noun) Systematic errors which may be positive or negative. Bitter (taste) (adj.) Describes the basic taste produced by dilute aqueous solutions of various substances such as quinine and caffeine. Comparative assessment Comparison of stimuli presented at the same time. Consumer (noun) Person who uses a product. Contrast effect Increase in response to differences between two simultaneous or consecutive stimuli. Control (noun) Sample of the material under test chosen as a reference point against which all other samples are compared. Convergence effect Decrease in response to differences between two simultaneous or consecutive stimuli. Detection threshold Minimum value of a sensory stimulus needed to give rise to a sensation. The sen• sation need not be identified. Difference test Any method of test involving comparison between samples. Difference threshold Value of the smallest perceptible difference in the physical intensity of a stimulus. NOTE: In English, the term "difference threshold" is sometimes designated by the letters "DL" (difference limen) or the ini• tials "JND" Gust noticeable difference). Appendix B 183

Discrimination (noun) Act of qualitative and/or quantitative differ• entiation between two or more stimuli. Duo-trio test Method of difference testing in which the control is presented first, followed by two samples, one of which is the same as the control sample. The assessor is asked to identify the sample which is different from the control. Error (of assessment) The difference between the observed value (or assessment) and the true value. Expert (noun) In the general , a person who, through knowledge or experience, has competence to give an opinion in the fields about which he or she is consulted. Expert Assessor Selected assessor with a high degree of sen• sory sensitivity and experience of sensory methodology, who is able to make consis• tent and repeatable sensory assessments of various products. Hedonic (adj.) Relating to like or dislike. Hedonic scale Scale expressing degrees of like or dislike. Independent assessment Evaluation of one or more stimuli without direct comparison.

Interval scale Scale where numbers are chosen in such a way that equal numerical intervals are as• sumed to correspond to equal differences in sensory perception.

Magnitude estimation Process of assigning values to the intensities of an attribute in such a way that the ratio of the value assigned and the assessor's per• ception are the same. Objective method Any method in which the effects of personal opinions are minimised. 184 GUIDELINES FOR SENSORY ANALYSIS

Off-flavour Atypical flavour often associated with dete• rioration or transformation of the product. Off-odour Atypical odour often associated with dete• rioration or transformation of the product. Ordinal scale Scale where points are arranged according to a pre-established or continuous progres• sion. Paired comparison test Method in which stimuli are presented in pairs for comparison on the basis of some defined attributes. Panel (noun) Group of assessors chosen to participate in a sensory test. Perception Awareness of the effects of single or mul• tiple sensory stimuli. Preference (noun) Expression of the emotional state or reac• tion of an assessor which leads him or her to find one product better than one or several others. Preference test Test to assess preference between two or several samples. Profile The use of descriptive terms in evaluating the sensory attribute of a sample and the in• tensity of each attribute. Quality (noun) Collection of features and characteristics of a product or service that confer its ability to satisfy stated or implied needs. Ranking (noun) Method of classification in which a series of samples is placed in order of intensity or de• gree of some specified attribute. This pro• cess is ordinal with no attempt made to as• sess the magnitude of the differences. Rating (noun) Method of classification according to cat- Appendix B 185

egories, each of which is placed on an ordi• nal scale. Ratio scale Scale where numbers are chosen in such a way that equal numerical ratios are assumed to correspond to equal sensory perception ratios. Recognition threshold Minimum value of a sensory stimulus per• mitting identification of the sensation per• ceived. Reference (noun) Substance, different from the material under test, used to define an attribute or a specified level of a given attribute. Residual taste (noun) Olfactory and/or gustatory sensation which occurs after the elimination of the product and which differs from the sensations per• ceived whilst the product was in the mouth. Salty (taste) (adj.) Describes the basic taste produced by aque• ous solutions of various substances such as . Scale (noun) Continuum, divided into successive values, which may be graphical, descriptive, or nu• merical, used in reporting the level of a characteristic. Scale (hedonic) Scale expressing degrees of like or dislike. Scale (interval) Scale where numbers are chosen in such a way that equal numerical intervals are as• sumed to correspond to equal differences in sensory perception. Scale (ordinal) Scale where points are arranged according to a pre-established or continuous progres• SIOn. Scale (ratio) Scale where numbers are chosen in such a way that equal numerical ratios are assumed 186 GUIDELINES FOR SENSORY ANALYSIS

to correspond to equal sensory perception ratios. Scoring (noun) Method of evaluation of a product or of the attributes of a product by means of scores (having a mathematical significance). Screening (noun) Preliminary selection procedure. Selected assessor Assessor chosen for his or her ability to per• form a sensory test. Sensory (adj.) Relating to the use of the sense organs. Sensory adaptation Temporary modification of the sensitivity of a sense organ due to continued and/or re- peated stimulation. Sensory analysis Examination of the sensory attributes of a product by the sense organs. Sensory fatigue Form of sensory adaptation in which a de• crease in sensitivity occurs. Specialised expert assessor Expert assessor who has additional experi• ence as a specialist in the product and/or process and/or marketing, and who is able to perform sensory analysis of the product and to evaluate or predict effects of variations relating to raw materials, recipes, process• ing, storage, ageing, etc. Stimulus threshold Minimum value of a sensory stimulus needed to give rise to a sensation. The sen• sation need not be identified. Subjective method Any method in which the personal opinions are taken into consideration. Sweet (taste) (adj.) Describes the basic taste produced by aque• ous solutions of various substances such as sucrose. Taint Taste or odour foreign to the product. Appendix B 187

Triangle test Method of difference testing involving the simultaneous presentation of three coded samples, two of which are identical. The as• sessor is asked to select the sample per• ceived as different. --ApPENDIX C Some Useful Contacts

INFORMATION ABOUT PUBLISHED STANDARDS (ISOIBSI)

BSI Customer Services 389 Chiswick High Road London W4 4AL u.K. Tel: +44 (0)181 9969000 Fax: +44 (0)181 9967400

ASTM 100 Bar Harbor Drive West Conshohocken, PA 19428-2959 U.S.A. Tel: +1 (610) 832 9585 Fax: + 1 (610) 832 9555 e-mail: [email protected]

TRAINING COURSES IN SENSORY STATISTICS

Statistics for Industry 4 Victoria Avenue Knaresborough, North Yorkshire HG5 9EU u.K. Tel: +44 (0)1423865955 Fax: +44 (0)1423 865711

189 190 GUIDELINES FOR SENSORY ANALYSIS

ADVICE ON SENSORY ANALYSIS Campden & Chorleywood Food Research Association Chipping Campden, Gloucestershire, GL55 6LD U.K. Tel: +44 (0)1386 842000 Fax: +44 (0)1386 842100 e-mail: [email protected]

Leatherhead Food Research Association Randalls Road Leatherhead, Surrey KT22 7RY England, U.K. Tel: +44 (0)1372 376761 Fax: +44 (0)1372 386228

SOFTWARE FOR SENSORY DATA-CAPTURE Biosystemes, (FIZZ) 9, rue des Mardors 21560 Coutemon, France Tel: +33 0380475762 Fax: +33 0380475071 e-mail: [email protected]

Compusense 150 Research Lane Guelph,Ontario Canada Nl G 4T2 Tel: +1 5198369993 Fax: +15198369898 e-mail: [email protected]

SOCIETIES AND PROFESSIONAL BODIES The Market Research Society 15 Northburgh Street London, EC 1V OAR U.K. Tel: +44 (0)171 4904911 Appendix C 191

Fax: +44 (0) 171 490 0608 e-mail: [email protected]

STATISTICAL PACKAGES

GENSTAT

NAG Ltd. Wilkinson House Jordon Hill Road Oxford, Oxfordshire OX2 8DR U.K. Tel: + 44 (0)1865-53233

MINITAB Minitab Ltd. 3 Mercia Business Village Torwood Close Westwood Business Park Coventry, Warwickshire CV4 8HX u.K. Tel: + 44 (0)1203-695730

Minitab Inc. 3081 Enterprise Drive State College, PA 16801 U.S.A. Tel: + 1-814-238-3280

SAS

SAS Software Ltd. Wittington House Henley Road Medmenham, Marlow, Bucks SL7 2EB u.K. Tel: + 44 (0) 1628-486933 SAS Institute Inc. Box 8000, SAS Circle 192 GUIDELINES FOR SENSORY ANALYSIS

Cary, NC 27511-8000 U.S.A. Tel: + 1-919-942-7273

SENPAK

Reading Scientific Services Ltd. Lord Zuckennan Research Centre Whiteknights P.O. Box 234 Reading, Berks RG6 2LA u.K. Tel: + 44 (0)1734-868541

SEN STAT

Sensory Research Laboratories Ltd. 4 High Street Nailsea, Bristol, BS19 IBW u.K. Tel: + 44 (0)1275-810183

STATGRAPHICS

Manugistics Inc. 2115 East Jefferson Street Rockville, MD 20852-4999 U.S.A. Tel: + 1-301-984-5412

Cocking and Drury Ltd. 180 Tottenham Court Road London, WIP 9LE U.K. Tel: + 44 (0) 171-4369481

STATISTICA

Statsoft Ltd. 21-23 Mill Street Appendix C 193

Bedford, Bedfordshire, MK40 3EX U.K. Tel: + 44 (0)1234 341226

Statsoft, Inc. 2300 East 14th Street Tulsa, OK 74104 U.S.A. Tel: + 1-918-749-1119

S-PLUS StatSci Europe OsneyHouse Mill Street Oxford, Oxfordshire OX2 OJX U.K. Tel: + 44 (0)1865-200952 SPSS SPSS UK Ltd. 9-11 Queens Road Walton-on-Thames, Surrey, KT12 5LU U.K. Tel + 44 (0)1932-566262

SPSS Inc. 444 North Michigan Avenue Chicago, IL, 60611 U.S.A. SYSTAT CLECOM The Computer Algebra Centre The Research Park Vincent Drive Edgbaston, Birmingham B 15 2SQ U.K. Tel: + 44 (0)121-471-4199 Bibliography

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Beauchamp, G. 1990. Research in chemosensation related to flavour and fragrance percep• tion. 44, no. 1: 98-100. Bourne, M.C. 1982. Food texture and viscosity: Concept and measurement. London: Aca• demic Press. Brandt, M.A. et aI. 1963. Texture profile method. Journal ofFood Science 28: 404-409. British Standards Institution. 1982. BS 5929: Methods for sensory analysis offoods. Part 2: Paired comparison test. London. British Standards Institution. 1984. BS 5929: Methods for sensory analysis offoods. Part 3: Triangle test. London. British Standards Institution. 1986a. BS 5929: Methodsfor sensory analysis offoods. Part 1: General guide to methodology. London. British Standards Institution. 1986b. BS 5929: Methods for sensory analysis offoods. Part 4: Flavour profile methods. London. British Standards Institution. 1989. BS 5929: Methods for sensory analysis offoods. Part 6: Ranking. London. British Standards Institution. 1989. BS 7183: British standard guide to design oftest rooms for sensory analysis offoods. London. British Standards Institution. 1992. BS 5098: Glossary ofterms relating to sensory analy• sis. London. British Standards Institution. 1992. BS 5929: Methodsfor sensory analysis offood. Part 9: Initiation and training ofassessors in the detection and recognition ofodours. London. British Standards Institution. 1992. BS 5929: Methods for sensory analysis offood. Part 8: Duo-trio test. London. British Standards Institution. 1992. BS 5929: Methods for sensory analysis offood. Part 7: Investigating sensitivity oftaste. London. British Standards Institution. 1993. BS 7667: Assessors for sensory analysis. Part 1. Guide to the selection, training and monitoring ofselected assessors. London. British Standards Institution. 1994. BS 7667: Assessors for sensory analysis. Part 2. Guide to the selection, training and monitoring ofexperts. London. Brown, W. 1997. Contribution oforal breakdown to individual differences in flavour and texture perception. (Talk given at the SCI Meeting on Individual Differences in Sensory Perception and Product Choice, London, April 1997), 14-15. Cardello, A.V. 1996. The role of the human in food behaviour: II. Texture. Cereal World 41, no. 6: 469-470. Cardello, A.V. 1996. The role of the human senses in food behaviour: III. Taste. Cereal Foods World 41, no. 9: 751-753. Cairncross, E.E., and L.B. Sjostrom. 1950. profiles: A new approach to flavor prob• lems. Food Technology 4, no. 8: 308-11. Chatfield, C. 1983. Statistics for technology. London: Chapman & Hall. Chatfield, C., and A.J. Collins. 1980. Introduction to multivariate analysis. London: Chapman & Hall. Bibliography 197

Civille, G. V., and B.G. Lyon. 1996. Aroma and flavour lexicon for sensory evaluation: Terms, definitions, references and examples. ASTM data series publication DS66. Phila• delphia: American Society for Testing and Materials. Cochran, W.G., and G.M. Cox. 1957. Experimental designs. New York: John Wiley & Sons. Danzart, M. 1986. Univariate procedures. In Statistical procedures in food research, ed. J.R. Piggott, 19-59. London: Elsevier Applied Science Publishers. Department of Health, Advisory Committee on Novel Foods and Processes. 1991. Guide• lines on the conduct of taste trials involving novel foods or foods produced by novel processes. London. Edgell, A. et al. 1987. EMG-A new concept in texture measurement. Dairy Indust. Int. 52, no. 5: 27-29. European Organisation for Quality Control. 1976. Glossary of terms used in quality con• trol. Bern, Switzerland. European Sensory Network. 1996. A European sensory and consumer study: A case study on coffee. Chipping Campden, U.K. (Available from CCFRA, Chipping Campden, Gloucestershire, GL55 6LD, U.K.). Fransella, F., and D. Bannister. 1977. A manual for repertory grid technique. London: Aca• demic Press. Gacula, M.C., and J. Singh. 1984. Statistical methods in food and consumer research. Lon• don: Academic Press. Gower, J.e. 1975. Generalized Procrustes analysis. Psychometrika 40, no. 1: 33-51. Greenbaum, T.L. 1988. The practical handbook and guide to focus group research. Toronto: Lexington Books. Guinard, J-X., and R. Mazzucchelli. 1996. The sensory perception of texture and mouthfeel. Trends in and Technology 7: 213-219. Harper, R. 1972. Human senses in action. Edinburgh: Churchill Livingstone. Horwitz, W. 1988. Protocol for the design, conduct and interpretation of collaborative stud• ies. Pure and Applied Chemistry 60, no. 6: 855-864. Hutchings, J.B., and P.J. Lillford. 1988. The perception offood texture-the philosophy of the breakdown path. Journal of Texture Studies 19: 103-115. Institute of Brewing. 1995. Sensory analysis manual. London. (Available from Institute of Brewing, 33 Clarges St., London WIY 8EE, u.K.). Institute of Brewing Analytical Committee. 1997. Health and safety aspects: General policy statement. London. International (ISO). 1991. Methods for sensory analysis offood. Part 7. Investigating sensitivity oftaste. ISO 3972. International Standards Orgzanization (ISO). 1992. Sensory analysis-vocabulary. ISO 5492. Ishihara, S. 1973. Tests for colour blindness. Tokyo: Kanehara Shuppan Co. 198 GUIDELINES FOR SENSORY ANALYSIS

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A Atmosphere and shelf life, 4 Acceptance tests, 49-53 and taint, 6 hedonic rating, 50-51 monadic tests, 50 multi-sample ranking for preference, B 52-53 number of assessors for, 79 Balanced incomplete block design, order paired comparison test, 51-52 effects evaluation, 103, 105 paired tests, 50 Box-and-whisker diagrams, 116 repeat paired comparison test, 52 Brightness, visual assessment, 16 and replication, 101 sensory assessors for, 77-78 sensory assessors training, 87 sequential monadic tests, 50 c standard products in, 137 statistical analysis of data, 115-117 Canonical variate analysis, 115 Adaptation Carriers, and product testing, 66-67 and sensory assessment, 33 Carry--over (precedence) effect, and taste, 20 63--64 Age, in sensory assessment, 29 Certification studies, purpose of, 141 Ageusia, 20 Cigarette , and taste, 21 Alternative hypothesis, 119 Clarity, visual assessment, 16 Analysis of variance (ANOVA), 111, Client, needslrequirements of, 36 112-113 Closed-response questions, 55, extension of, 112-113 55-56 Friedman ranked ANOVA, 115 Cluster analysis, 115 order effects evaluation, 102 Colds, and odor assessment, 19 Association effects, 31 Collaborative studies, purpose of, 141

201 202 GUIDELINES FOR SENSORY ANALYSIS

Color statistical software, 120 and flavor, 26 See also Statistics visual assessment, 15-16 Data collection Color blindness, 15 computer as tool, 38, 40 Color discrimination, testing for, 15 report section, 124 Commercial products, 67 Decoration, and visual assessment, 17 Complete factorial design, 99 Descriptive profiling, 47-48 COMPUSENSE, 120 Descriptive tests, 46-49 Concurrence matrix, order effects consensus profiling, 46-47 evaluation, 103, 104, 105 descriptive profiling, 47-48 Confidence intervals, 110 free-choice profiling, 48-49 Confounding, 103 number of assessors for, 79 Consensus profiling, 46-47 panel requirements, 49 Constraints in sensory analysis, 131-132 phases in testing, 46 cost constraints, 132-133 sensory assessors for, 76-77 product constraints, 131-132 sensory assessors training, 84-87 in report, 123 standard products in, 136-137 time constraints, 132 statistical analysis of data, 109 Consumer panel, 45, 49, 53 Detection threshold, 27 Continuous line-scale, 38, 39, 48 Difference from control test, 42 Control products Difference tests, 41-45, 138 blind control, 99 difference from control test, 42 as calibration standard, 99 duo-trio test, 42 in experiment, 98 levels of questioning, 41 sensory assessor training, 86 magnitude estimation, 45 Correlation, assessor performance number of assessors for, 79 monitoring, 140 paired comparison test, 42 Correlation coefficient, 117-118 panel requirements for, 45 Correspondence analysis, 114 ranking test, 44-45 Cost constraints, 132-133 sensory assessors for, 76 Cross-laboratory studies, types of, 141 sensory assessors training, 83 triangle test, 43-44 two-out-of-five test, 44 D Difference threshold, 27 Discriminant analysis, 115 Data analysis, 40-41, 106-120 Discrimination tests for acceptance tests, 115-117 standard products, 136 for descriptive tests, 109-115 statistical analysis of data, 109 for discrimination tests, 109 Discussion section, reports, 126 hypothesis testing, 119-120 Disinfectants, and taint, 6 normal distribution of data, 108-109 Distractions, and sensory assessment, for relating data, 117-119 33 report section, 124 Distribution, and shelf life, 5 statistical methods, 107-108 Duo-trio test, 42 Bibliography 203

E and interaction of senses, 26 perception, stages of, 25-26 Eating, oral processing of food, stages of, Flooring, and taint, 6 23 Food labels, use by date, 3-4 Electromyography (EMG), 24 (General Food Hygiene) Equipment Regulations 1995, 88 requirements, 131 Forced-choice option, triangle test, 43 safety precautions, 89 Fractional factorial design, 99 Evenness, visual assessment, 16 Free--choice profiling, 48-49 Expectation, and sensory assessment, 26, Friedman ranked analysis of variance, 31 45,115 Experimental design control products, 98 factorial designs, 99-100 G number of assessors, 100 and number of products, 97, Gender differences, in sensory 101-102 assessment, 29 order effects, evaluation of, 102-106 Generalized Procrustes analysis, 48-49, purpose of, 95-96 113,114 reference products, 98 Genetic factors replication, 100-101 in sensory assessment, 30 session effect, evaluation of, 98 and taste, 20-21 size of difference between products, GENSTAT, 120 100 Graphical methods, 107, 116 statistical issues, 96 histograms, 107, 116, 117 within-sample variation, analysis of, line graphs, 107, 163 97-98 panel performance monitoring case Experimental products, 67 example, 171-175 Exploratory statistics, 109-110, 115 External preference mapping, 118 Eye, operation of, 14 H

Habituation, and sensory assessment, F 33 Halo effect, and sensory assessment, Factor analysis, 114 32-33 Factorial designs, 99-100 Health, and odor assessment, 19 complete factorial design, 99 Hedonic rating, 50-51 fractional factorial design, 99 hedonic scale, 51, 116, 117 Fatigue, and taste, 20 Histograms, 107, 116 First order effect, 63 information from, 116, 117 FIZZ, 120 Hue, visual assessment, 15 Flavor, 25 Hypogesia, 20 definition of, 25 Hypothesis testing, 119-120 204 GUIDELINES FOR SENSORY ANALYSIS

alternative hypothesis, 119 Market research, product matching, 7-8 null hypothesis, 119 Mastication, process of, 23 Type I error, 119-120 Methods section, reports, 123-124 Type II error, 119-120 MINITAB, 120 Monadic tests, 50 Mood, and sensory assessment, 34 I Motivation, and sensory assessment, 34 Multiple comparison tests, statistical, Ideal-point model, 119 112 Individual differences, 28-30 Multiple linear regression, 118 age, 29 Multi-sample ranking for preference, gender, 29 52-53 genetic factors, 30 Multivariate analysis, 107, 113 importance of, 28 physiological state, 29-30 psychological factors, 30 N Interpretation section, reports, 126 Internal preference mapping, 117, 118 Night blindness, 15 Interquartile range, 116 Nominal scale, 37 Interval scale, 37-38, 39, 51 Non-parametric methods, 107-108 N<>-perceivable-difference option, triangle test, 43-44 K Normal distribution, of data, 108-109 Nose, and smell, 17 Kruskal Wallis test, 115 Null hypothesis, 119

L o Latin Square, order effects evaluation, 102,103 Objectives, in reports, 122 Leniency, and sensory assessment, 33 Odor assessment Lighting factors affecting assessment, 18-19 and shelf life, 4 sniff for evaluation of odors, 17-18 test area requirements, 130 One-tailed test, 109 and visual assessment, 16--17 One-way analysis of variance, III Line graphs, 107 Open-ended questions, 55 example of, 163 Order effects, 63 Location, and odor assessment, 18-19 causes of, 102 Logic error, and sensory assessment, 32 Order effects evaluation, 102-106 analysis of variance, 102 M balanced incomplete block design, 103,105 Magnitude estimation, 45 concurrence matrix, 103, 104, 105 Mann-Whitney U test, 115 Latin Square, 102, 103 Mapping. See Product mapping Ordinal scale, 37, 39 Bibliography 205

p Physiological state, in sensory assessment, 29-30 Packaging Portion size, and visual assessment, 17 and shelf life, 4 Preference, external preference mapping, and taint, 6 118 Paired-comparison test, 42, 51-52, 115 Preference mapping, 163-167 repeat test, 52 coffee analysis example, 163-166 Paired t-test, 110 goalof,157 Palate cleanser, 65 internal preference mapping, 117, 118 types of, 65 preference map, example of, 166 Panel leader, role of, 71-72 preference segmentation chart, 165 Panels relationship of consumer preferences/ for acceptance tests, 53 sensory attributes, 166-167 consumer panel, 45, 49, 53 Presentation odor, and sensory and descriptive tests, 49 assessment, 32 for difference tests, 45 Principal--component analysis, 113-114, performance monitoring, 13 7-140 160 ring tests, comparative checks, 140- regression analysis, 118 141 Product acceptability, 11 trained panel, 45, 49, 53 and customer requirements, 11 untrained panel, 45, 49, 53 Product batching, case example, 169-170 See also Sensory assessors Product constraints, and testing, 131-132 Parametric methods, 107 Product mapping, 9-10 Partialleast-squares regression analysis, aim of, 158 118 based on sensory profiles, 10 Perception, definition of, 13 and future product development, 161- Performance monitoring 162 criteria of assessor performance, 139- interpretation of map, 9-10 140 panels for, 160 cross-laboratory studies, 141 preference mapping, 163-167 graphical methods case example, 171- preparation of product, 159-160 175 results, 160, 162 panels, 137-140 samples for testing, 158-159 and standard products, 138-139 Product matching, 7-8 Personal habits, of sensory assessors, 73 goalof,157 Personality factors market research, 7-8 and sensory assessment, 34 and target product, 7 of sensory assessors, 73-74 Product reformulation, 8-9 Physiological sensations, 13-28 necessity of, 8-9 interaction of senses, 21-27 and sensory analysis, 9 sensitivity of, 27 Products, safety precautions, 89-90 sight, 14-17 Product specification, 2-3 smell, 17-19 case example, 143-145 taste, 19-21 and quality control, 2-3 and threshold, 27 sensory specifications, 2-3 206 GUIDELINES FOR SENSORY ANALYSIS

Product testing Q amount of product required, 68-{)9 Quadratic regression analysis, 118 carrier/food medium for, 66--(j7 Quality, defmition of, 2 carry-over (precedence) effect, Quality control 63--64 and product batching case example, context of test, 62 169-170 finished product and testing, 62 and product specification, 2-3 first order effect, 63 and product specification case limitations in, 69-70 example, 143-145 methods for, 69 sensory assessors for, 75 number of products presented, 70, Questionnaire design 101-102 closed-response questions, 55, 55-56 order effect, 63 fmal questionnaire, 58 palatability of products, 60--61 length factors, 56 palate cleanser, 65 and location of testing, 54-55 relevance to testing objective, 60 open-ended questions, 55 safety of product, 60 order of questions, 56-57 session effect, 64 and type of panel, 54 special practical difficulties, wording of questions, 57-58 62--63 Questionnaire layout, sensory assessor and strong /odors, 64-65 training, 86 temperature factors, 65--66 and visual differences, 65 whole product or part, 61 R See also Experimental design Product types Ranking tests, 44-45 commercial products, 67 number of assessors for, 79 experimental products, 67 sensory assessors training, 83-84 Proficiency studies, purpose of, 141 statistical, 115 Psychological factors, 31-34 Rating tests adaptation, 33 number of assessors for, 79 association effects, 31 sensory assessors training, 84 distractions, 33 Ratio scale, 38, 39, 51 expectation, 31 Recognition threshold, 27 habituation, 33 Recommendations section, reports, halo effect, 32-33 126 leniency, 33 Records, retaining, 127 logic error, 32 Reference products, in experiment, 98 personality factors, 34 References, in reports, 122 presentation odor, 32 Regression analysis, 118 psychology/physiology link, 31 multiple linear regression, 118 in sensory assessment, 30 partialleast-squares regression stimulus, 32 analysis, 118 Bibliography 207

principal-component regression interval scale, 37-38, 39, 51 analysis, 118 nominal scale, 37 quadratic regression analysis, 118 ordinal scale, 37, 39 simple linear regression analysis, 118 ratio scale, 38, 39, 51 Relating data, statistical analysis for, sensory assessor training, 84-85 117-119 SENPAK,120 Repeatability, assessor monitoring, 139 Senses. See Physiological sensations Repeat paired comparison test, 52 Sensitivity, measurement of, 27 Replication, 100--101 Sensory analysis and acceptability tests, 101 cost/time factors, 36 definition of, 100--10 1 data collection/analysis, 37--41 number required, 101 definition of, 13 Reports and individual differences, 28-30 audience for, 121-122 and perception, 13 comments in, 125 and physiological sensations, 13-28 constraints in, 123 for product acceptability, 11 data analysis section, 124 for product mapping, 9-10 data collection method, 124 for product matching, 7-8 discussion section, 126 for product reformulation, 8-9 experimental details in, 123-124 psychological factors, 31-34 functions of, 121 purposes of, 1,35-36 interpretation section, 126 scaling method, 37-38 introduction in, 122 shelf-life studies, 3-5 methods section, 123-124 steps in, 27 objectives, 122 for taint potential, 5-7 recommendations section, 126 terminology, listing of, 181-187 references in, 122 Sensory analysis process results section, 124-125 assessor briefing, 134-135 Results section, reports, 124-125 constraints, 131-13 2 Ring tests, comparing panels, 140--141 cost factors, 133 equipment, 131 facilities, 129 s incentives for assessors, 135 organizing testing, 133-134 Safety, 60, 89-93 performance monitoring of assessors/ equipment risks, 89 panels, 137-141 general policy statement, 92-93 product standards, 135-137 product risks, 89-90 test area requirements, 129-130 of sensory assessors, 88-91 Sensory analysis tests test environment risks, 90 acceptance tests, 49-53 test protocol risks, 91 descriptive tests, 46--49 SAS, 120 difference tests, 41--45 Scaling method, 37-38 Sensory aspects of food continuous line-scale, 38, 39 analysis of, 26-27 208 GUIDELINES FOR SENSORY ANALYSIS

flavor, 25 Smell, 17-19 interaction of, 26 assessment of, 18 texture, 21-25 defects of, 18 Sensory assessors and flavor, 26 for acceptance tests, 77-78 nose, operation, of, 17 briefing for test, 134-135 See also Odor assessment for descriptive tests, 76-77 Social conditioning, and sensory for difference tests, 76 assessment, 34 health and welfare of, 88-91 Software, statistical packages, 120 number required, 78-79 Sound performance monitoring, 137-140 and flavor, 26 qualifications of, 72-74 and texture, 26 for quality control tasks, 75 Spider plot, 117 selection criteria, 80-82 S-PLUS, 120 solutions for taste assessments, 80 SPSS, 120 special incentives for, 135 Standard products, 135-137 for taint tests, 76 in acceptance tests, 13 7 Sensory assessors training in descriptive tests, 136-137 for acceptance tests, 87 in discrimination tests, 136 for descriptive tests, 84-87 performance monitoring of panel, for difference tests, 83 138-139 general training, 82-83 uses of, 136 for ranking tests, 83-84 Standard Statistical Tables, 138 Sensory elements, of food product, 2 STAT-GRAPHICS, 120 Sensory specifications, 2-3 Statistics SEN STAT, 120 analysis of variance (ANOVA), Ill, Sequential analysis, 44 112-113 Sequential monadic tests, 50 canonical variate analysis, 115 Session effect, 64 cluster analysis, 115 evaluation of, 98 confidence intervals, 110 Shape, visual assessment, 16 confounding, 103 Shelf-life studies, 3-5 correlation coefficient, 117-118 case example, 145-147 correspondence analysis, 114 conditions affecting shelf-life, 4-5 discriminant analysis, 115 purpose of, 3 and experimental design, 96 Shine, visual assessment, 16 exploratory statistics, 109-110, 115 Sight, 14-17 external preference mapping, 118 color , 15 factor analysis, 114 defective, forms of, 15 factorial designs, 99-100 eye, operation of, 14 Friedman ranked analysis of variance, See also Visual assessment 115 Significance tests, 138 generalized Procrustes analysis (GPA), Simple linear regression analysis, 118 114 Size, visual assessment, 16 graphical methods, 107, 116 Bibliography 209

hypothesis testing, 119-120 Taint potential, 5-7 ideal-point model, 119 and sensory analysis, 6-7 internal preference mapping, sources of taint, 6 117,118 Taint prevention, case example, 153-155 interquartile range, 116 Taint tests Kruskal Wallis test, 115 screening of assessors for, 80-81 Mann-Whitney U test, 115 sensory assessors for, 76 multiple comparison tests, 112 Taste, 19-21 multivariate analysis, 113 defects of, 20 multivariate methods, 107 physiological factors in, 19-20 non-parametric methods, 107-108 Taste assessment one-tailed test, 109 factors affecting assessment, 20-21 one-way analysis of variance, 111 technique for tasting, 21 order effects evaluation, 102-106 Temperature paired-comparison test, 115 and product testing, 65-66 paired t-test, 110 and shelf life, 4 parametric methods, 107 Test environment, safety precautions, principal component analysis, 90 113-114 Test protocol, safety precautions, 91 ranking test, 115 Texture, 21-25 regression analysis, 118 characteristics of, 23-24 t-test, 108 definition of, 22 two-dimensional plots, 117 importance in product acceptance, 22 two-product t-test, 110 phases in assessment of, 24 two-tailed test, 109 senses used in assessment of, 22-23 two-way analysis of variance, 111 sensory/instrumental measurement of, two-way analysis of variance with 24-25 interaction, 111-112 and sound, 26 univariate methods, 107 visual assessment, 16 vector model, 119 Threshold, types of, 27 Wilcoxon test, 116 Time constraints, 132 See also Data analysis Trained panel, 45, 49, 53 Stimulus, and sensory assessment, 32 Triangle test, 43-44, 138 Storage, and shelf life, 5 forced-choice option, 43 Sweetener synergy, 31 no-perceivable-difference option, SYSTAT,120 43-44 sequential analysis, 44 T-test, 108 T paired t-test, 110 two-product t-test, 110 Tables, for sensory tests, 178-179 Two-dimensional plots, 117 Taint, meaning of, 5 Two--out-of-five test, 44 Taint investigation, case example, Two-product t-test, 110 149-151 Two-tailed test, 109 210 GUIDELINES FOR SENSORY ANALYSIS

Two-way analysis of variance, III Vision. See Sight with interaction, 111-112 Visual assessment factors affecting Type I error, 119-120 assessment, 16-17 Type II error, 119-120 features for measurement of, 15-16 importance in sensory analysis, 14,27 u Vocabulary and terms, sensory assessor training, 85 Univariate methods, 107 Volatility, and odor assessment, 19 Untrained panel, 45, 49, 53 Use by date, 3-4 w

v Wilcoxon test, 116 Word generation, sensory assessor Vector model, 119 training, 85