a group experience in sensory evaluation - meat science

384 A GROUP EXPERIENCE IN SENSORY EWAIUATION*

D . G . CORNISH and R. E. BALDWIN Oscar Mayer & Co. and

University of Missouri

Yesterday, most of the RMC conference members participated i n the Analyses have wiener t a s t e test conducted j u s t before the noon lunch.

been conducted on the data from tha t t e s t . This session is t o inform you of the outcome of some of those analyses.

Before showing you some of the analyt ical resu l t s , I would l i ke t o mention a few reasons f o r performing t h i s exercise. F i r s t , the organizers of t h i s meeting believed it would be interest ing f o r those i n attendance t o par t ic ipate d i rec t ly i n the generation of information f o r t h i s par t of the program. Secondly, it was considered tha t it may be of i n t e re s t t o demonstrate the powers of time-share computers and terminals.

The products you evaluated i n yesterday's t e s t were production wieners. composition and nut r i t iona l information of pork and of beef wieners a r e presented i n tab le 1. However, f o r the t a s t e t e s t , random code numbers were assigned t o the samples and placement on the t r ay a l so was randomly assigned. The design of the test w a s balanced so that half of the participants tas ted pork first and half tas ted beef f i r s t . The meat formulation of the pork wieners w a s predominantly pork trim w i t h some beef trim, while the meat formulation of t he beef wieners w a s lo@ beef tr im. The wiener made from a combination of pork and beef will be referred t o as pork wiener throughout t h i s presentation.

They were designated as pork wieners and beef wieners. The

You were asked t o record your evaluation on a ba l lo t shown i n figure 1. You were a l so asked t o indicate some information concerning your personal background. of t he information in to the computer system.

This bal lot has been coded t o enable entry

Yesterday's sensory t e s t would be considered a preference t e s t w i t h hedonic ra t ings. direct ion of choice end sometimes the extent t o which a product appeals t o some population. preference f o r one sample over another, a large number of panelists is desirable.

The objectives of a preference t e s t a re t o predict

To obtain a measure of consumer reaction or

These panelists not only need not, but should not, be trained.

The t a s t e tes t data from yesterday's session was analyzed by using a portable terminal. 350 c i t i e s i n North America w i t h data processing service. used t o input the t a s t e test data were as follows:

This par t icular terminal has the a b i l i t y t o access The methods

* Presented a t the 28th Annual Reciprocal Meat Conference of the American Meat Science Association, 1975.

W IENEK EVALUATION k I G U 1 , L 1 0

T a s t e t h e samples i n the o r d e r t h e y a r e p r e s e n t e d , from l e f t t o r i g h t . Clear

y o u r iiiouth with a s i p of water b e f o r e t a s t i n g e a c h . I n d i c a t e how well you l i k e

o r d i s l i k e t h e p r o d u c t s b y p l a c i n g a clieck mark on t h e scales be low:

S m i P L E POR K W I E ~ J ER s SAMPLE R F F F WMERS

__ L L I K E VERY MUCH A_- ____ 5 L I K E MODERATELY 5

4 LIKE S L I G H T L Y 4 - 3 D I S L I K E S L I G H T L Y 3

1 D I S L I K E VERY MUCH 1 2 D I S L I K E MODERATELY 7

P L E A S E PLACE A CHECK MARK I N THE A P P R O P R I A T E CATEGORIES BELOW:

1. EMPLOYMENT : 5. SMOKE:

1 E d u c a t i o n

7 Government

1 Yes

2 No

6 . GEOGRAPHICAL LOCATlON 3 I n d u s t r y

_LJ-- ~ e s e a r c t i 1 West ( A )

7 Nor th C e n t r a l ( B ) Lnstitute ( e g . , A . M . l . F . , WARF)

2 . EDUCATlON:

1 High School

7 B.S.

3 M.S.

4 P h . D .

3 . AGE:

1 d. 20

2 20-29

3 30-39

5 50-59

6 > 59

4 40-49

--

3 N o r t h East (C)

4 S o u t h ( D )

5 Foreign

38 6

U ~ E I L L . . I CORPOS I T I O J A i W IIIUTR I T I Oi4AL I i4FORI"IAT I Oil OF PORK AND OF BEEF \!I ENERS

P 0 R lLk/ ~ F J I H S. -- R EEF\JI61\LER-S.

I p i ~ l < \ - [ ~ ~ ~ ~ ~ - ~ ~ ; POICI;, \ I A I E R , E E E F , B E E F , H A T ~ ~ , CORN SYRUP,

SALT, CORN SYRUP,

S O D I UM ASCORBATE,

SALT, FLAVORING, DEx-mosE,

SODIUII NITRITE DEXTROSE , FLAVOR I NG,

SO11 1 U M N I T I: I TE

P A P R I K A , S O D I U M ASCORBATE,

I'J UT R I T I 0 14 A 1 V A LU E S / L I I 1 K CALOR I ES : 140 1'10 PROTE I N : 5 GM 5 GM

C A 13 130 H YD R A T E : 2 GM 2 GM FAT : 13 GM 13 GM

PRO-I-E IN : V I T , A,: VIT, C I :

R IBOFLAV IN : IJ I A C I rd :

I R O N :

-rH I AM I N E :

CALC I UM:

X OF U I S , RDA 10 0 15 4 2 4 0 2 2 6 2

10 0

15 0 2 4 0 2 2 8 2

38 7

1. Dial the telephone access number i n S t . Louis.

2 . Type i n the coded information from each ba l lo t using the portable terminal.

3. Store data, and request a "canned program" run.

4. Instruct the computer t o run the desired program and l i s t the r e su l t s .

The s t a t i s t i c a l systems or "canned programs" tha t a r e available with t h i s par t icular u n i t are l i s t e d i n table 2 . The systems tha t were used i n analyzing the data f romthe t a s t e t e s t are the last 8 programs.

Figures 2 and 3 i l l u s t r a t e the computer's a b i l i t y t o generate a bargraph. areas who participated i n yesterday's t e s t . 3 ) shows the number of people a t each educational l eve l who participated i n the t a s t e t e s t . The information provided i n these bargraphs indicate t h a t the majority of the panel participants were from education f i e l d and had F'h.D. degrees.

Figure 2 shows the number of people from four employment The next bargraph (figure

The computer system i s also capable of producing data i n histogram form. The upper half of f igure 4 i l l u s t r a t e s the number of people who f e l l into different age groups. The histogram on the lower portion of the flgure 4 deals with the number of paxticipants from di f fe ren t geographical locations.

The computer w a s requested t o display frequency tables on male/ female and smoker/non-smoker r a t io s . The r e su l t s a r e shown in tab le 3 .

The information which I have described thus f a r has deal t with the personal prof i les of the participants i n yesterday's t a s t e t e s t . The next 2 figures show how the participants rated pork wieners and beef wieners. This information i s given i n the form of simple s t a t i s t i c s and histograms. Figure 5 i l l u s t r a t e s the dis t r ibut ion of ratings given exclusively t o pork wieners. The dis t r ibut ion of ra t ings given t o beef wieners i s contained i n f igure 6.

The information provided i n t ab le 4 summarizes the data acquired i n the t a s t e t e s t broken down according t o employment, education, age, sex, smokers and geographical location. The resu l t s shown i n t h i s table make it possible t o rapidly scan the data and provide a basis f o r deciding i f fur ther s t a t i s t i c a l analyses a re desirable or necessary. it is impossible t o Judge from the information provided i n t h i s table whether or not a s ignif icant difference ex is t s between the overal l mean of the ra t ing given t o pork wieners versus the overal l ra t ing given t o beef wieners.

For example,

The computer w a s asked t o provide a t - s t a t i s t i c which can be used t o determine i f the overal l mean of the ratings given t o pork wieners and the overal l mean of the ratings given t o beef wieners are s i g n i f i - cantly different . The " t " - s t a t i s t i c for the overal l means i s shown i n

FH EQ

0

0

EDUCAT I ON 1 36

GOVEHNNENT 15

INDUSTRY 32

RESEARCH INSTITUTE 1 1

0

e

e

-_- e

0 e

a

e

Fti Ell

0

0

2

27

52

1 1 5

0

0

NOTE: HEHL E A C h ' & ' h€.,FHESENTS 2 OBSERVATIONS.

AGE F H EG]

0 0

54 53 38 28 1 H 0 0

EhEO 0 CI 1 0 11 u u 0 0 0 0 0 7 0 0 0 0 0 0 0 0 0

31 0 0 0 0 0 0 0 0 0

91 0 0 ti 0 0 0 0 0 0

66

S M P L E STATISTICS b O h PORK

NO. OF' ODSEHVATlONS 146

S e 0 9 1 b 4 0 e 8 2 3 6 3 2 * G ( J O U U 6.00000

392

E HEO 0 0 5 0 0 0 0

1 6 u 0 0 0

44 0 0 0 0 72 0 0 0 0

59 0 0

A V E U G E : STANDARD DEVIATION 8 SbiLLEST OBSEHVA T I ON : LAhGEST OBSEHVATION 8

196

393

IkIjLk, ‘1. STATISTICAL ANALYSIS MODULES

REGRESSION ANALYSI s ONE-\/AY ANALYSIS OF VARIANCE 2 AND 5 FACTOR ANALYSIS OF VARIANCE WEIBULL RELIABILITY ANALYS I s CHI -SQUARE TEST EXPONENT I AL SMOOTH I NG POLYNOMIAL CURVE FITTING LEAST SQUARES POLYNOMIAL FIT CONFIDENCE LIMITS AUTOCORRELATION LEAST SQUARES REGRESSION CORRELATION VATR IX

REGRESSION ANALYSIS ON BIVARIATE DATA GROWTH RATE CALCULATION I ~ V I N G AVERAGES FITS FOR NEIGHTED DATA POLYNOMIAL BARGRAPH

FREQUENCY TABLE SIMPLE STATI ST I cs T-TEST

MULTIPLE REGRESSION X-Y PLOT

FREQUENCY COUNT OF TWO CROSS V A R I A B L E S

11 I STOGRAM

CORR E L A T I ON

394

FIiEDUENCY TABLE FOR SEXCODE

CUM* CUM. FFi EQ PCT. E HEGi P C l .

MALE 184 93.88 164 9 3 . 8 8 FEbiALE 12 6.12 196 100.00

F h E Q U U C Y TAELE FOR SWOHCODE

CUM. CUM. FR EQ P C T * Fh EQ PCT*

YES 70 35.71 70 35.71 NO 126 64.29 A96 1 0 0 * 0 0

'lAt3LE 4.

UlP LO Y Pi EN 1'

SAMPLE STATISTICS

EIJUCATION

I NDU s 'rLY I;E:s EAli CH I Eu s 1 I 'AUlE

G o v EWN EN 'r

H I G b SCHOOL B.S. M.S. El1.D.

AGE

SLX

SMOKE

YES NO

GEOGHAPHIC LOCAI'ION

WEST NOh 1'H C EN 1'FiAL NOFr'I'h EAST SOCIl'H F ON E I GN

NO. OF FOhK BEEF OBSEWV. MEAN S O D . M E A N S . D .

136 5 .2 U.b 4.9 1.0 i s 4.9 0.8 5.1 1 . 1 32 4.9 0 . 8 4.3 0.9

4.b 0.9 5.2 0.8 11

2 5.5 0.7 5.0 1.4 27 4.8 0.9 4.5 0.9 52 5.1 0.8 4.8 1.0

1 1 5 5.1 0 08 4 . 9 1.1

0 0. 0. 0. 0. 59 5.1 0.9 4.& 0.9 53 5.1 0.9 4.b 1.1 38 5.1 u.7 5.0 1 . 1 28 5.2 0.4 4.9 1.0 18 5.2 0.6 4.6 1 . 1

184 5.1 0.8 4.8 1.0 12 5.5 0 . 5 5.4 1.0

70 5.1 0.7 4.7 1 . 1 126 5.1 0.5 4.9 1.0

19 5.1 0.8 4.5 1.0 58 5.1 0 . 8 4.9 1.0 2 1 4.9 1 .0 4 . 5 1.0 52 5.2 0.8 5.1 0.9 6 5.0 0. 4.3 1.4

396 tab le 5 . A s ign i f icant ly (P < 0.05) higher ra t ing was given t o the pork wieners when compared t o beef wieners . The t - s t a t i s t i c can be used t o determine more subt le e f fec ts on ratings. For example, the comparison of preference t o pork wieners between males and females ( tab le 6 ) , and the difference i n preference t o pork wieners between smokers and non-smokers (table 7). The r e su l t s indicate there was no s igni f icant difference i n preference t o pork wieners between males and females or between smokers and non-smokers.

The relat ionship of the rat ings given t o pork wieners as influenced by age of par t ic ipants m i g h t be useful ly subjected t o fur ther evaluation. Therefore, the computer was instructed t o produce a ser ies of equations t o describe the relat ionship between these two variables. This infor- mation is s h m i n t ab le 8. The curve with the la rges t index i s the b e s t - f i t . Curve 5 , y=l/(a+B%) re su l t s i n an index of determination of 0.005C8. indicate l i t t l e o r no relat ionship between the rat ings given t o pork wieners and age of the judge.

The index of determination i s r2. Thus, t he r e su l t s

Another capabi l i ty of the computer and terminal system is t o produce multiple regression and multiple correlat ion coeff ic ients as shown i n t ab le 9. The r e su l t s indicate tha t there i s l i t t l e o r no relat ionship of the ra t ing given t o pork wieners t o age and education of the pane l i s t .

A simple but in te res t ing system capabi l i ty is the production of x-y p lo t s . beef wieners on the basis of age c lass i f ica t ion .

Figure 7 shows the means of the rat ings given t o pork and

I n summary, there a re no s e t formulas that can be universally applied t o analyze sensory problems. evaluate i t s own needs and desires and develop sensory capabi l i t i es i n accordance w i t h those needs. For example, this computer system functions very wel l f o r Market Research people who conduct tests on new products. I n t h i s example, a prompt, r e l i ab le feedback of consumer opinion i s needed.

Each company or i n s t i t u t ion must

Today I have presented a portion of the t o t a l amount of data which The terminal which was used i n analyzing data from th is

I have the terminal was generated. sensory t e s t was furnished by General Elec t r ic Co. i n the educational exhibi t room f o r those of you interested. output yesterday cost $27 and took 1 5 minutes f o r r e t r i v a l .

The data

I would l i k e t o thank our hosts here a t Missouri f o r the telephone hook-up provided a t the conference. Baldwin and her staff f o r conducting the sensory t e s t , and a l so fo r help in analyzing the r e s u l t s .

A spec ia l thanks f o r D r . Ruth

IhL hOLLOWING b O U H h k P O l h E 3 E S khL OPTIONAL EOH CALCULAlION O F A I - S I A T I S l l C Oh 1 H E IrEANS OF SAMFLE VAfiIABLES POL)< & BEEF

C O k P U 1 E ; D ?' VALUE DEGkE.ES OF FREEDOPI 2 70820 390 .oo

2 - l A I LLD PliOBAE I L I TY 0 0 0 7 0 6

I'AI3ULAR "T" VALUES 1.96 (P.*.05) 2.137 ( P . < . O l )

THE FOLLOWING FQUh hYFOlhIESES A R E OPTIONAL FOR C A L C U L A T I O N OF A T - S T A T I S T I C ON 'i'hE MEANS OP SAMPLE VAKIARLES FkPiALE & PKF'EMALE

1 FIEAN OF PIWALE = GIVEN VALUE 2 P r U N O F PKE-ALE = N U N OF PHFENALEJ ASSUMING 2 VARIANCES ARE EQUAL 3 M I A N OF PKPiiLE = M E A N OF PHFEPALE, ASSUMING 2 VAHIANCES ARE UNEQUAL 4 ~ v I J A N OF PXMALE = M E A N OF FKFEPALE, khEHt THE Vlll iIABLES A R E HELfi'I'LD 5 EXIT EhOh TTESTo

HYPOTHESIS TYPE --?2

CO.PiUTED T VALUE - 1 . 7 8 1 1 9

DEGHEES OF F'HEEDOM 2 - TA I LED PH OBAB I L I 1Y 194000 0 007645

TAbULAR "T" VALUES 1.96 < P . < o O 5 ) 2 . 9 7 < P . < . O l )

399

THE FOLLOWING F O U H hYPOTHESES ARE OPTIONAL FOR CALCULATION OF A T - S T A ' I I S T I C ON 1 h E PiFANS O F SAMPLE VARIABLES PKSMOKE & PKNOSMOIi

1 NEAN O F PKSMOKE = GIVEN VALUE 2 M E A N O F PKSMOKE = hWiV O F PKNOSMOKI ASSUMING 2 VARIANCES ARE EQUAL 3 MEAN Ob PKSPiOIiG = PIEAN OF PKNOSIVIOKI ASSUMING 2 VAZiIANCES A R E UNEQUAL 4 M E A N O F PKSPiOKE = N U N OF PKNOSKOKI WHEFrE THE V A h I H b L E S AHE HLLATLD 5 E X 1 1 FROM ?'TEST.

HYPOTHESIS TYPE --?2

COtiPUTED T VALUE DEGREES OF FREEDOM 2 - T A I LEIj PRODAD I L 1 TY 0 046436 1 9 4 * O O 0 64291

TABULAR "T" VALUES 1 * 9 8 (P.<.O5) 2 . 9 7 < P . < * 0 1 1

400

Y U A I I I A R L E : P O H H X bAii I A D L E AGECOLE

XbIEAN: 3*454062E+OO YMEAN: 5.041837E+00

N U P B E& CURVE 1 NDEX A B

1 Y =A +u "X 0.00140 5*01006E+00 2 *36747E* 2 k =AU EN- (B*X 1 0 000265 4088889E+00 7042731E. 3 Y=A'( x -B 1 0.00234 4.681 75E+OU 2.3 1 €55 4E. 4 k = A + ( B / X ) 0 ~ O 0 U 6 4 5.14854E+CJO - 1 *70%69E* 5 k = 1 / <A+BQX 1 O O U 0 5 0 0 2.11142k-01 -20 3641 3 E 6 Y=X /<A *x +B > U.O(j400 1 *95523E-01 2023827E

4 01

XFIEAN YMEAN 5*091837E+00

3 *4540b2E+UO 3*4%8571E+00

RULTIPLE C O R F i E L A T I O N COEFFIC I ENT = 9 *242587E-02

COEFFICIENTS E S T OF SD 6 661 6443E-03 9 5558 14 S E - 0 2

4 7589427E-02 8 10 402 52s-08

F U A I ' I O ( 2 ~ 1 4 3 DEGREES OF FREEDOM)= 80314581E-01

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D . H. Kropf: I ' ve j u s t discovered i n t a l k i n g with Dwight Loveday that our North Cen t ra l da t a i s contaminated, he was r a i sed below t h e Mason-Dixon l i n e and he wrote down North Cent ra l .

E . C . Allen: I ' ve always been curious i n formulations such as t h i s . How m c h do you have t o change them t o ge t d i f f e rences between beef and pork? Is th i s t y p i c a l what you normally f ind?

D . G . Cornish: The formula which was used i n yes te rday ' s t a s t e t e s t was 60$7 pork and 4C$ beef. t o sp ice d i f f e rence . However, t h e wieners used yesterday are market standard items.

Some of t h e f l a v o r d i f f e rence is due

R . L. Henrickson: W h a t was t h e function of paprika? Flavor or color?

D . G . Cornish: Color.

D . H. Kropf: I s t i l l remember t h e number of my sample. Could you g ive us t h e code? Odd or even? What was t h e code?

D . G . Cornish: The odd numbered sample was pork and t h e even number sample was bee f .

R . E. Baldwin: Normally I wouldn't have done that. It f a c i l i t a t e d decoding t h e raw d a t a . i n t e r e s t i n g that you were able t o d e t e c t t h a t d i f f e rence on t h e b a l l o t .

Usually I would a s s ign random numbers. It was

M. C . Brockmann: How on e a r t h d id you g e t a n a l y t i c a l moisture t o equal p rec i se ly four times p ro te in plus lo?

D . G . Cornish: That's a s e c r e t .

J. H. Z ieg ler : We promised t o give you t h e opportunity t o a s k questions--we d i d n ' t guarantee any answers.

J . W . Carpenter: How is t h e a c c e p t a b i l i t y of t hese two wieners on f l a v o r w i t h cost?

D . G . Cornish: Currently t h e cos t of t hese two wieners a r e equal ly p r i ced . The r e l a t i o n s h i p that these two va r i ab le s have on acceptance is probably based on personal preference, d i e t , e t c . The d i f f e rence t h a t each cont r ibu te t o acceptance--1 couldn't t e l l you.