MULTIVARIATE ANALYSIS OF DATA IN SENSORY SCIENCE
CHAPTER 1 A DESCRIPTION OF SAMPLE DATA SETS USED IN FURTHER CHAPTERS 1 CHAPTER 2 PANELIST AND PANEL PERFORMANCE A MULTIVARIATE EXPERIENCE 19 CHAPTER 3 A NONTECHNICAL DESCRIPTION OF PREFERENCE MAPPING 41 CHAPTER 4 DETERMINISTIC EXTENSIONS TO PREFERENCE MAPPING TECHNIQUES 61 CHAPTER 5 MULTIDIMENSIONAL SCALING AND UNFOLDING AND THE APPLICATION OF PROBABILISTIC UNFOLDING TO MODEL PREFERENCE DATA 87 CHAPTER 6 CONSUMER SEGMENTATION TECHNIQUES 103 CHAPTER 7 ORDINAL LOGISTIC REGRESSION MODELS IN CONSUMER RESEARCH 121 CHAPTER 8 RISK ASSESSMENT IN SENSORY AND CONSUMER SCIENCE 155 CHAPTER 9 APPLICATION OF MARS TO PREFERENCE MAPPING 171 CHAPTER 10 ANALYSIS OF JUST ABOUT RIGHT DATA 199 CONTENTS 1 A DESCRIPTION OF SAMPLE DATA SETS USED IN FURTHER CHAPTERS 1 1 A DESCRIPTION OF EXAMPLE DATA SETS THE VARIOUS DATA SETS DESCRIBED HERE ARE USED IN VARIOUS CHAPTERS OF THE BOOK BUT WE THOUGHT IT WOULD BE USEFUL TO DESCRIBE THE METHODOLOGIES IN A LITTLE MORE DETAIL HERE THE ACTUAL DATA CAN BE DOWNLOADED FROM THE BOOK WEB SITE AT HTTP WWW UARK EDU UA MULTIVARIATE INDEX HTM 1 1 1 WHITE CORN TORTILLA CHIPS 1 1 1 1 INTRODUCTION THIS DATA SET IS USED EXTENSIVELY AS AN EXAMPLE IN CHAPTERS 3 4 5 AND 7 ADDITIONAL DETAILS ABOUT THESE STUDIES ARE PUBLISHED IN MEULLENET ET AL 2002 AND 2003 HOUSEHOLDS IN THE UNITED STATES ARE VERY FOND OF SALTY SNACKS INCLUDING TORTILLA CHIPS ACCORDING TO DIES 2000 76 OF U S HOUSEHOLDS PURCHASE TORTILLA CHIPS EVERY 32 DAYS IN 1996 TORTILLA AND POTATO CHIPS ACCOUNTED FOR VE OF THE TOP 10 PRODUCTS IN THE SALTY SNACK CATEGORY ANONY MOUS 1998 IN THE UNITED STATES TORTILLA CHIPS HAVE A 20 MARKET SHARE OF SALTY SNACK PURCHASES SECOND ONLY TO POTATO CHIPS LISSER 1993 IN 1996 TORTILLA CHIPS ENJOYED THEIR HIGHEST SALES IN 10 YEARS AND YELLOW TORTILLA CHIPS GAINED IN POPULARITY WELLMAN 1997 A FEW STUDIES HAVE BEEN CARRIED OUT FOR THE EVALUATION OF THE SENSORY PROPERTIES OF TORTILLA CHIPS BUTTERY AND LING 1995 1998 CHARACTERIZED THE AVOR VOLATILES OF CORN TORTILLA CHIPS WHEREAS HAWRYSH ET AL 1995 EXAMINED THE SENSORY AND CHEMICAL STABILITY OF TORTILLA CHIPS FRIED IN CANOLA OIL CORN OIL AND PARTIALLY HYDROGENATED SOYBEAN OIL STINSON AND TOMASSETTI 1995 SHOWED THAT THE AVOR AND TEXTURE ACCEPTABILITY OF LOW FAT TORTILLA CHIPS INCREASED WHEN NATURAL CORN AVOR WAS ADDED HOWEVER THE CONSUMER PREFERENCE PATTERN OF WHITE CORN TORTILLA CHIPS IS NOT YET CLEARLY DE NED THIS STUDY WAS CONDUCTED TO DETERMINE THE PREFERENCES FOR TORTILLA CHIPS AND TO QUANTIFY THE SPECI C SENSORY CHARACTER ISTICS FOUND IN THE TORTILLA CHIPS PRESENTLY ON THE MARKET 1 1 1 2 SAMPLES A BROAD RANGE OF 25 COMMERCIALLY AVAILABLE TORTILLA CHIPS WERE PURCHASED AT LOCAL SUPER MARKETS THE ORIGINAL GROUP OF TORTILLA CHIPS WHICH INCLUDED BOTH YELLOW AND WHITE CORN CHIPS WAS VISUALLY SCREENED BASED ON COLOR SHAPE AND LEVELS OF SALT AND FAT REPORTED ON THE LABELS ELEVEN COMMERCIALLY AVAILABLE TOASTED WHITE CORN TORTILLA CHIP PRODUCTS TABLE 1 1 WERE SELECTED FOR THIS STUDY BECAUSE WHITE CORN TORTILLA CHIPS ARE MORE POPULAR WITH CONSUMERS THAN YELLOW CORN TORTILLA CHIPS AND THERE WAS A NANCIAL CONSTRAINT FOR THIS PROJECT LARGE BAGS OF EACH OF THE 11 TYPES OF TORTILLA CHIPS WERE PURCHASED 1 2 DAYS BEFORE TESTING THE SAMPLES WERE RANDOMLY CODED WITH A THREE DIGIT NUMBER AND STORED TO PREVENT FRACTIONING OF CHIPS 1 THE CODED SAMPLES WERE PRESENTED TO PANELISTS ON WHITE PLASTIC PLATES THAT WERE 6 INCHES IN DIAMETER APPROXIMATELY VE OR SIX LARGE CHIPS OR SIX TO EIGHT BITE SIZE CHIPS WERE PLACED ON EACH PLATE EACH BAG OF CHIPS WAS IMMEDIATELY RESEALED USING A BAG CLIP TO PRESERVE FRESHNESS CHIPS THAT WERE EXCESSIVELY FRACTURED WERE DISCARDED 1 1 1 3 DESCRIPTIVE ANALYSIS ELEVEN TORTILLA CHIP SAMPLES WERE EVALUATED FOR APPEARANCE AVOR AND TEXTURE BY A GROUP OF NINE SPECTRUM TRAINED PANELISTS PANEL ORIENTATION WAS CONDUCTED TO DEVELOP A DESCRIP TIVE LEXICON FOR THE APPEARANCE AVOR AND TEXTURE ATTRIBUTES SPECI C TO TORTILLA CHIPS USING THE SPECTRUM METHOD SENSORY SPECTRUM INC CHATHAM NJ REFERENCES USED FOR PANEL ORIENTATION AND LEXICON DEVELOPMENT ARE PRESENTED IN TABLES 1 2 1 3 AND 1 4 THE PANEL ORIENTATION ON TORTILLA CHIP TEXTURE AVOR AND APPEARANCE WAS CONDUCTED OVER THREE 3 HOUR SESSIONS THE TEXTURE BALLOT ANALYZED FOUR MAJOR CATEGORIES OF PRODUCT TEXTURE CHARACTERISTICS SURFACE RST BITE CHEW DOWN AND RESIDUAL FOR A TOTAL OF 15 TEXTURE ATTRIBUTES TABLE 1 2 THE AVOR BASIC TASTE AROMATICS FEELING FACTORS AND AFTERTASTE PRO LES CONSISTED OF 23 ATTRIBUTES TABLE 1 3 THE APPEARANCE BALLOT CONSISTED OF VE ATTRIBUTES TABLE 1 4 TEXTURE AVOR AND APPEARANCE EVALUATIONS WERE CARRIED OUT UNDER CONTROLLED CONDI TIONS OVER TWO 3 HOUR SESSIONS TWO 2 5 HOUR SESSIONS AND ONE 2 HOUR SESSION RESPEC TIVELY DURING EACH SESSION THE SAMPLES WERE PRESENTED IN A RANDOM ORDER TO EACH PANELIST I E EACH PANELISTS WAS ASSIGNED A DIFFERENT RANDOMIZATION SCHEME THE EVALUATION WAS PERFORMED IN INDIVIDUAL BOOTHS FEATURING CONTROLLED LIGHTING AND POSITIVE AIR PRESSURE PANELISTS WERE PROVIDED WITH A PAPER BALLOT REFERENCES AND CRACKERS NABISCO PREMIUM UNSALTED BRAND AND WATER FOR CLEANSING AND RINSING THEIR PALATES BETWEEN EACH SAMPLE A 10 MINUTE BREAK WAS SCHEDULED DURING EACH SESSION THE TEXTURE AND AVOR EVALUATIONS SALT CONTENT FAT CONTENT PRODUCT NAME ABBREVIATION PRODUCER SHAPE 1 1 BEST YET WHITE BYW FLEMING TRIANGLE 4 12 CORN COMPANIES INC GREEN MOUNTAIN GMG GREEN MOUNTAIN STRIP 5 13 GRINGO GRINGO GUY S RESTAURANT GUY GUY S SNACK FOODS ROUND 3 9 ROUNDS MEDALLION WHITE MED MEDALLION FOOD TRIANGLE 2 11 CORN CORPORATION MISSION STRIPS MIS MISSION FOOD STRIP 4 10 CORPORATION MISSION TRIANGLE MIT MISSION FOOD TRIANGLE 4 10 CORPORATION OAK CREEK OAK OAK CREEK ROUND 2 11 FARMS WHITE FARMS CORN SANTITA S SAN FRITO LAY TRIANGLE 5 8 TOM S WHITE CORN TOM TOM S FOODS INC TRIANGLE 5 10 TOSTITO S BITE SIZE TOB FRITO LAY ROUND 5 12 TOSTITO S TOR FRITO LAY TRIANGLE 3 9 RESTAURANT STYLE TABLE 1 1 COMMERCIAL PURE WHITE CORN TORTILLA CHIP PRODUCTS 1EXPRESSED AS PERCENTAGE DAILY INTAKE PERCENTAGE DAILY VALUE IS BASED ON A 2000 CALORIE DIET MULTIVARIATE ANALYSIS OF DATA IN SENSORY SCIENCE 2 TERM1 DE NITION TECHNIQUE REFERENCE SURFACE CHARACTERISTICS ROUGHNESS THE AMOUNT OF IRREGULAR HOLD SAMPLE TO MOUTH AND GRAHAM CRACKER PARTICLES IN THE SURFACE FEEL THE SURFACE OF THE MICRO 1 0 OF THE SAMPLE SAMPLE WITH TONGUE MACRO 1 5 MICRO THE SMALL CREVICES AND LIPS CLUB CRACKER AND IRREGULARITIES ON THE MICRO 3 5 SURFACE OF THE SAMPLE MACRO 2 5 MACRO THE LARGE PEAKS COOKIE AND SLOPED ANGLES MICRO 0 8 DETECTED ON THE SURFACE MACRO 5 0 OF THE SAMPLE PRINGLES MICRO 8 0 MACRO 1 0 TWIZZLER MICRO 0 5 MACRO 7 0 GRANOLA BAR MICRO 12 0 MACRO 1 0 TRISCUIT MICRO 13 0 MACRO 4 0 RYE WAFER MICRO 15 0 MACRO 0 0 NUTRAGEOUS MICRO 14 0 OILY GREASY LIPS THE AMOUNT OF OILY OR PLACE SAMPLE BETWEEN LIPS CLUB CRACKER 5 0 GREASY RESIDUE COMPRESS AND RELEASE PRINGLES 8 0 REGARDLESS OF THE USING THE TONGUE TO FEEL THICKNESS FELT ON THE THE SURFACE OF THE LIPS LIPS AFTER PLACING THE EVALUATE THE AMOUNT OF SAMPLE IN MOUTH OILY GREASY RESIDUE FELT ON THE LIPS LOOSE PARTICLES THE AMOUNT OF PARTICLES COMPRESS SAMPLE LIGHTLY PRINGLES 5 0 FELT ON THE LIPS BETWEEN LIPS REMOVE SAMPLE AND EVALUATE FIRST BITE HARDNESS THE FORCE REQUIRED TO COMPRESS OR BITE THROUGH CREAM CHEESE 1 0 COMPRESS THE SAMPLE SAMPLE ONE TIME WITH EGG WHITE 2 5 MOLARS OR INCISORS AMERICAN CHEESE 4 5 BEEF FRANKFURTER 5 5 OLIVE 7 0 PEANUT 9 5 ALMOND 11 0 CARROTS 11 0 LIFESAVERS 14 5 CRISPINESS THE AMOUNT OF SMALL COMPRESS SAMPLE WITH GRANOLA BARS 2 0 BREAKS FELT PERCEIVED AS MOLAR TEETH UNTIL CLUB CRACKER 5 0 HAVING MANY LIGHT AIRY SAMPLE SHATTERS BREAKS GRAHAM CRACKER 6 5 SMALL BREAKS AND THE OR CRUMBLES CHEERIOS 7 0 CONTINUED TABLE 1 2 TEXTURE VOCABULARY FOR TORTILLA CHIPS MULTIVARIATE ANALYSIS OF DATA IN SENSORY SCIENCE 3 TERM1 DE NITION TECHNIQUE REFERENCE DEGREE OF PITCH AND BRAN AKES 9 5 SOUND HEARD WHEN THE GOLD SH CRACKERS 11 0 SAMPLE IS CRACKED BROKEN CORN AKES 14 0 OR COMPRESSED ONCE CHEW DOWN CHARACTERISTICS COHESIVENESS OF THE AMOUNT THAT THE CHEWED CHEW SAMPLE WITH MOLAR SHOESTRING MASS SAMPLE HOLDS TOGETHER TEETH 8 10 TIMES AND LICORICE 0 0 EVALUATE CARROTS 2 0 MUSHROOMS 4 0 BEEF FRANKFURTER 7 5 AMERICAN CHEESE 9 0 BROWNIE 13 0 DOUGH 15 0 MOISTNESS OF THE AMOUNT OF WETNESS CHEW SAMPLE WITH MOLAR SALTINE CRACKERS 4 5 MASS OILINESS FELT ON THE SURFACE TEETH 8 10 CHEWS AND POUND CAKE 10 5 OF THE MASS EVALUATE HOW WET DOES JELL O GELATIN 14 0 THE SAMPLE FEEL WATER 15 0 ROUGHNESS OF MASS THE AMOUNT OF ROUGHNESS CHEW SAMPLE WITH MOLARS UNCHEWED JELL O PERCEIVED IN THE CHEWED 8 10 TIMES AND EVALUATE GELATIN 0 0 SAMPLE THE IRREGULARITIES IN THE ORANGE PEEL 3 0 SAMPLE MASS COOKED OATS 6 5 PRINGLES 8 0 MOISTURE THE AMOUNT OF SALIVA CHEW THE SAMPLE WITH SHOESTRING LICORICE 0 0 ABSORPTION ABSORBED BY THE SAMPLE MOLAR TEETH 8 10 TIMES LICORICE 3 5 DURING MASTICATION AND EVALUATE POPCORN 7 5 PAY ATTENTION TO HOW DRY POTATO CHIPS 10 0 YOUR MOUTH IS BECOMING POUND CAKE 13 0 NOT TO THE SAMPLE SALTINE CRACKERS 15 0 PERSISTENCE OF CRISP THE AMOUNT OF MASTICATION CHEW SAMPLE WITH MOLARS BEFORE THE CRISP SOUND AND COUNT THE NUMBER CHANGES OF CHEWS COMPLETED BEFORE THE PITCH OR CRISP SOUND CHANGES RESIDUAL CHARACTERISTICS OILY GREASY LM THE AMOUNT AND DEGREE OF EXPECTORATE THE SAMPLE SALTINE CRACKERS 0 5 RESIDUE FELT BY THE TONGUE AND FEEL THE SURFACE OF RITZ CRACKERS 2 5 WHEN MOVED OVER THE THE MOUTH WITH TONGUE PRINGLES 5 0 SURFACE OF THE MOUTH TO EVALUATE OIL 15 0 TOOTHPACK THE AMOUNT OF PRODUCT CHEW SAMPLE 15 20 TIMES CAPTAIN CRUNCH PACKED INTO THE CROWNS EXPECTORATE AND FEEL THE CEREAL 5 0 OF YOUR TEETH AFTER SURFACE OF THE CROWNS OF HEATH BAR 10 0 MASTICATION THE TEETH TO EVALUATE LOOSE PARTICLES THE AMOUNT OF PARTICLES CHEW SAMPLE WITH MOLARS CARROT 10 0 REMAINING IN AND ON THE SWALLOW AND EVALUATE SURFACE OF THE MOUTH AFTER SWALLOWING 1THE DATA FOR ROUGHNESS HARDNESS COHESIVENESS OF MASS ROUGHNESS OF MASS TOOTHPACK AND LOOSE PARTICLES WERE FROM THE WORK BY MEULLENET AND OTHERS 1999 2001 THOSE FOR MOISTURE OF ABSORPTION WAS FROM THE WORK BY MEILGAARD ET AL 1999 THE REMAINING DATA WERE FROM THIS STUDY TABLE 1 2 CONTINUED MULTIVARIATE ANALYSIS OF DATA IN SENSORY SCIENCE 4