Objective Assessment of Pork Quality

8/2/2019 Objective Assessment of Pork Quality

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ELSEVIER

Meat Science37 (1994) 41 142 0 1994 ElsevierScienceLimitedPrinted in Grea t B ritain. All rights reserved0309-1740/94/$7.00

O b j e c t i v e A s s e s s m e n t o f P o r k Q u a l i t y

M. D. Garrido, J . Pedauy6, S . Baf i6n & J . LaencinaT e c n o l o g l a d e l o s A l im e n t o s , F a c u l t a d V e t e ri n a r ia ,C a m p u s d e E s p i n a r d o , 30 071 M u r c i a , S p a i n

( R e c e i v e d 2 4 M a y 1 99 3; r e v i s e d v e r s i o n re c e i v e d 1 0 J u n e 1 99 3; a c c e p t e d 7 J u l y 1 99 3)

ABSTRACTSeveral objective methods for estimating pork quality were studied." internallight scattering (FOP) , electrical conductivity (EC) , pH, colour, waterholding capacity (WHC), soluble proteins (SP), pigment content, intra-muscular fat (i.m. fa t), and moisture. The measurements were made onthe S e m i m e m b r a n o s u s and L o n g i s s i m u s t h o r a c i s at 45 rain and 24 h p o s tm o r t e m in some cases and on the S e m i m e m b r a n o s u s in others.

Most of the measurements are significantly different between normal,PSE and DFD quality categories.There is a good correlation between pH values in both muscles:

pH4sSM-pH45LT (r=O. 74) and pH24SM-pHz4LT (r=O. 71). At 45 rain theeorrelation of EC with FOP and pH was r=0.56 and r=~).48 respectively.Lower correlations were found in other parameters.The results from principal component analysis (P CA ) showed that thethree first components explained 60.3% of the total variation and the mostimportant variables fo r the first PC were pH45 and EC45.

I N T R O D U C T I O NT h e g r o w i n g i n t er e st o f c o n s u m e r s i n m e a t q u a l it y a n d t h a t o f th e m e a ti n d u s t r y i n s a t i s f y i n g t h i s i n t e r e s t a n d s e l e c t i n g t h e m o s t a p p r o p i a t e u s ef o r i ts p r o d u c t s a r e s u f fi c ie n t j u s t if i c a ti o n f o r t h e d e v e l o p m e n t o f p r o b e sf o r c a t e g o r i z i n g m e a t s o o n a f t e r s l a u g h t e r a n d o t h e r r e l a t e d s t u d i e s .M o s t o f t h e s e p r o b e s a r e b a s e d o n t h e o p t i c a l a n d e l e ct r ic a l p r o p e r t ie s o fm u s c l e .

T h e m e a s u r e m e n t s o f i n t e r n a l l i g h t s c a t t e r i n g b y f i b r e o p t i c p r o b e( F O P ) a n d o f e le c t r ic a l c o n d u c t i v i t y b y q u a l i t y m e t e r ar e tw o a l te r n a t iv e st o p H m e a s u r e m e n t s f o r t h e c l a s si fi ca t i on o f P S E a n d D F D m e a t s

411


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412 M . D. G arrido, J . PedauyO , S. Ba~6 n, J . La enc ina( M a c D o u g a l l , 1 98 4) s i n c e a p H m e t e r i s d i ff ic u lt t o u s e o n t h e s l a u g h t e rl in e . B o t h i n s t r u m e n t s a r e r o b u s t , e a s y t o u s e a n d d o n o t r e q u i r ec o n s t a n t r e c a l i b r a ti o n .E v a l u a t i n g c o l o u r b y c o l o r i m e t e r ( M i n o l t a , C o l o r m e t ) i s a n o t h e ra l t e r n a t i v e s i n c e P S E a n d D F D m e a t s a r e d i f f e r e n t i n t h i s r e s p e c t . V i s u a la s se s s m e n ts o f p o r k p a le n e s s b y o b s e r v e r p an e ls , w e r e r e p o r t e d t o s h o w al i n e a r c o r r e l a t i o n w i t h L * o r b r i g h t n e s s v a l u e s ( E l l i o t , 1 9 6 9 ; M a c D o u g a l le t a l . , 1 9 6 9 ; V a n d e r W a l e t a l . , 1 9 8 7 , 1 9 9 2 ; E i k e l e n b o 0 m e t a l . , 1992).T h e r e a r e o t h e r c h a r a c t e r i s t i c s o f t h e m u s c l e w h i c h v a r y a c c o r d i n g t oq u a li ty . I t h a s b e e n k n o w n , f o r e x a m p l e, t h a t t h e e x t e n t o f d e n a t u r a t i o n o ft h e m u s c l e p r o t e i n s d i f f e r s i n n o r m a l a n d P S E m e a t ( W i s m e r - P e d e r s e n ,1 9 5 9 ; B e n d a l l & L a w r i e , 1 9 6 4 ; M a c D o u g a l l & D i s n e y , 1 9 6 7 ) ) . T h u s , t h em e a s u r e m e n t o f p r o te i n s o lu b i li ty a n d o t h e r c h a r a c te r is t ic s o f m e a t s u c h a st h e c o n c e n t r a t i o n o f h a e m p i g m e n t s ( W a r r i s s e t a l . , 1 9 9 0 ; E i k e l e n b o o me t a l . , 1 9 9 2 ; T r o u t , 1 99 2), w a t e r h o l d i n g c a p a c i t y ( G r a u e t a l . , 1 9 5 3 ; B a r t o n -G a d e , 1 9 8 0 ; K a u f f m a n e t a l . , 1 9 8 6 ) a n d i n t r a m u s c u l a r f a t ( V a n d e r W a le t a l . , 1 9 9 2 ) c a n a ls o h e l p cl as s if y m e a t a l t h o u g h t h e d i s a d v a n t a g e o ft h es e m e t h o d s is t h a t t h e y a r e e s se n ti al ly d e s tr u c t iv e a n d d o n o t p r o v i d ei m m e d i a t e r e s u lt s.I n t h i s p a p e r , w e e v a l u a t e d i f f e r e n t i n s t r u m e n t a l a n d a n a l y t i c a l m e t h o d sa s p r e d i c t o r s o f p o r k m e a t q u a l i t y a n d t h e r e la t io n s h i p s b e t w e e n t h e sem e t h o d s b a s e d o n d a t a c o l le c t ed o v e r a p e r i o d o f 2 y e a r s fr o m p i gc a r c a s s e s i n t h e M u r c i a r e g i o n .

M A T E R I A L A N D M E T H O D ST h r e e h u n d r e d a n d t w e lv e p o r k c a rc a ss e s f r o m c o m m e r c i a l b r e e d s ( gilts :L a n d r a c e L a r g e W h i te ; b o a r s o f v a r i o u s b re e d s) w e r e t es te d . T h ea n i m a l s w e r e s l a u g h t e r e d i n a c c o r d a n c e w i t h S p a n i s h r e g u l a t i o n s ( R T S ,R . D . 3 2 6 3 , 2 6 11 7 6) . T h e d i s t a n c e b e t w e e n p ig f a r m a n d s l a u g h t e r h o u s ev a r i e d b e t w e e n 1 . 5 a n d 4 0 k m , a n d t h e r e s t p e r i o d a n d f a s t i n g f r o m 3 t o1 2 h . T h e a n i m a l s w e r e s t u n n e d b y e l e c t r o n a r c o s i s ( 1 1 0 - 2 7 5 V f o r 4 - 5 s )a n d c o n v e n t i o n a l c h i ll i n g ( 4 - 5 C f o r 2 4 h ) w ~as u s e d . T h e c a r c a s s e s w e r es a m p l e d r a n d o m l y w i t h a m a x i m u m o f 1 5 s a m p l e s p e r d a y o v e r a 1 2m o n t h p e r i o d . M e a s u r e m e n t s o f i n t e r n a l l ig h t s c at te r in g w i t h a F i b r eO p t i c P r o b e ( F O P , P r e m i e r E l e c tr o n i c s N o r t h e r n L t d , U K ) , e le c tr ic a lc o n d u c t i v i ty ( E C ) w i t h a Q u a l i t y M e t e r ( Q M , Q u a l i ty M e t e r, T e c h p r o n ,M u n i c h , G e r m a n y ) a n d p H ( p H m e t er C r is o n 5 06 w i t h I n g o l d X e r o l y tc o m b i n e d e l ec t ro d e ) , w e r e m a d e o n t h e l ef t s id e o f t h e c a r c a s s a t 45 m i n a n d24 h p o s t m o r t e m ( p m ) . T h e y w e r e c a r r i e d o u t i n t h e S e m i m e m b r a n o s u s( S M ) a n d L o n g i s s i m u s t h o r a c i s ( L T ) a t a p o s i t i o n b e t w e e n t h e t h i r d a n d


3/10

O b j e c t iv e a s s e s sm e n t o f p o r k q u a l i t y 413f o u r t h f r o m l a s t ri b . I n a l l c a s es , t h e a v e r a g e o f t ri p l i c a te r e a d i n g s w a sr e c o r d e d . T h e m e a t s w e r e c la ss if ie d a s D F D , n o r m a l a n d P S E a c c o r d in g toF O P , E C a n d p H m e a s u r em e n t s m a d e in th e L T a n d S M m u s cle s a t 45 m i na n d 2 4 h p m ( t en p a r a m e t e r s i n all ) a c c o r d i n g t o t h e f o l l o w i n g t h r e s h o l dv a l u e s ( G a r r i d o e t a l . , 1 99 2): F O P4 5 ( D F D < 1 8 < n o r m a I < 3 5 < P S E ) , FOP24( D F D < 2 5 < n o r m a l < 4 5 < P S E ) , E C ( D F D < 5 < n o r m a l < 1 0 < P S E ) , pH 4s( P S E < 5 . 8 < n o r m a l ) a n d p H24 ( n o r m a l < 6 . 2 < D F D ) . M e a t s w i t h f ew e r t h a ns e v en p a r a m e t e r s c o r r e s p o n d i n g t o a p a r t i c u l a r q u a l i t y w e r e c la ss if ie d asi n t e r m e d i a t e : s li g h tl y D F D o r s li gh tl y P S E . S a m p l e s o f S M w e r e r e m o v e d a t 2 4 h p m f o r c o l o u r m e a s u r e m e n t s( L * , a * , b * v a l u es ) u s i n g a M i n o l t a ( M i n o l t a C h r o m a m e t e r I I , C R 2 00 /0 8M i n o l t a C a m e r a C o . , L t d , J a p a n ), b e f o r e th e fa t w a s r e m o v e d f r o mt h e m e a t . T h e m e a s u r e m e n t s w e r e t a k e n o n a f re s h ly c u t s u rf a ce o f t h em u s c l e .A f t e r t h e s a m p l e s w e r e c u t, w a t e r h o l d i n g c a p a c i t y ( W H C ) , s o lu b i li ty o fp r o t e i n s ( S P ) , m o i s t u r e , i n t r a m u s c u l a r f a t ( i . m . f a t ) a n d h a e m p i g m e n tc o n c e n t r a t io n , w e r e d e te r m i n e d . T h e W H C ( % ) w a s d e t e r m i n e d a c c o r d in gt o t h e fi lt er p a p e r p r e ss m e t h o d o f G r a u a n d H a m m (1 9 53 ), a n d t h e S P( U A 4 g ) u s i n g B i u r e t r e a g e n t ( B a r t o n - G a d e , 1 98 0). M o i s t u r e ( % ) w a sa s s e ss e d b y t h e m e i h o d d e s c r i b e d i n t h e I S O r e g u l a t i o n s 1 44 2 w h i l e i .m .f a t (% ) w a s m e a s u r e d a c c o r d i n g t o I S O r e g u l a t io n s 1 443 a f t er p r i o rd i g e s t i o n o f t h e s a m p l e i n C 1 H . T h e f a t w a s e x t r a c t e d u s i n g p e t r o l e u me t h e r a s s o l v e n t .F u r t h e r s am p l es w e r e u s e d t o d e t e r m i n e p i g m e n t c o n c e n t r a t i o n ( m g /g )a c c o r d i n g t o T r o u t ( 1 9 9 1 ) . T h e s a m p l e s w e r e h o m o g e n i z e d i n p h o s p h a t eb u f f e r ( p H 6 . 5 ) a n d t r e a t e d w i t h T r i t o n X - 1 0 0 a n d s o d i u m n i t r a t e( 6 5 m M ) .T h e s t a t i s t i c a l s t u d y o f t h e r e s u l t s w a s c a r r i e d o u t u s i n g s i m p l e v a r i a n c ea n a l y s i s, P e a r s o n ' s c o r r e l a t io n s a n d p r i n c i p a l c o m p o n e n t a n a l y si s (P C A ) .

R E S U L T S A N D D I S C U S S I O NT a b l e 1 s h o w s th e m e a n , s t a n d a r d d e v i at io n a n d t h e m i n i m u m a n dm a x i m u m v a l u es o f t h e q u a l i t y c h a r ac t e ri s ti c s s tu d i e d . I t c a n b e s e en t h a tt h e F O P a n d E C v a lu e s in th e S M m u s c l e a r e s li gh tl y h i g h e r t h a n t h ec o r r e s p o n d i n g m e a s u r e m e n t s i n t h e L T . T h e p H v a l u e s a r e s i m i l a r t ot h o s e o b t a i n e d b y L 6 p e z - B o t e e t a l . ( 1 9 8 9 ) , w h i l e t h e F O P r e a d i n g s a r eb e l o w t h o s e f o u n d b y C h i zz o li n i e t a l . ( 1 9 9 1 ) a n d c l o s e t o t h o s e o b t a i n e db y W a r r is s e t a l . ( 19 8 9) . E l e c t r i c a l c o n d u c t i v i t y is b e l o w t h a t o b t a i n e d b yO l i v e r e t a l . ( 19 9 1 ), w h i l e t h e m e a n v a l u e s o f L * , a * a n d b * i n t h e S Mc o i n c i d e w i t h t h o s e o f O s t e r a n d F e w s o n , (1 99 0) .


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414 ~f. D. Garrido, J. PedauyO, S. Bagdn, J. Laencina

T A B L E 1M eans, Standard Deviations, Minimum and M aximum V alues of M eat Quality ChracteristicsN Mean SD Min Max

pH45 SM 312 6.30 0.40 5"08 7.20LD 312 6"30 0-40 5.20 7" 15

FOP45 SM 312 15"24 9.18 2150 60-00LD 312 10.12 6-73 1-00 46.00

EC45 SM 312 5.63 3.13 2-70 22.20LD 312 4-58 1-71 1.70 17-10

pH24 SM 312 5-82 0.22 5.39 6-70LD 312 5.82 0-22 5.30 6.89

FOP24 SM 312 25.51 11.45 3.00 64-00LD 312 21.08 8.22 4.00 45.00EC24 SM 312 7'66 2'97 2"60 16" 10

LD 312 4"27 1"64 1"80 10"70L* SM 178 46-23 5"87 30" 13 60-95a* SM 178 7-12 2.54 1.66 16-10b* SM 178 4.28 1.98 - 1.47 13.02T45 SM 301 39.18 1-89 31-10 42T24 SM 296 6.9 6-61 1 8I. m. fa t SM 207 1.47 0.60 0.53 3.92WHC SM 268 73.27 7-96 40.25 97.31SP SM 279 0.192 0.06 0.056 0.300Pigment SM 277 1.26 0.52 0.13 3-94

T h e i n t r a m u s c u l a r f a t c o n t e n t o f th e s a m p l e s a n a l y s e d w a s 1 . 5% , s im i l a rt o t h e 1 . 3 % o b t a i n e d b y D e V r i e s e t a l . ( 1 9 9 0 ) . T h i s p a r a m e t e r i s s i g -n i f i c a n t l y c o r r e l a t e d w i t h m a r b l i n g ( V a n d e r W a l e t a l . , 1 9 9 2 ) , h e n c ei t s i n t e r e s t a s a q u a l i t y f a c t o r . H o w e v e r , t h i s r e s u l t i s b e l o w t h e 2 %r e c o m m e n d e d i n D a n i s h s t u d ie s as a m a r k o f a c c e p ta b l e q u a l i ty ( B a r t o n -G a d e , 1 9 91 ). C o m p a r e d w i t h th e s t u d ie s o f L d p e z - B o t e e t a l . ( 1 9 8 9 ) a n dO l i v e r e t a l . ( 1 9 9 1 ) , t h e s o lu b l e p r o t e i n c o n c e n t r a t i o n i s h i g h e r .

T h e c h a r a ct e r is t ic s o f t h e sa m p l e s a c c o r d i n g t o q u a l i t y ( D F D , s l ig h t lyD F D , n o r m a l , s l ig h tl y P S E a n d P S E ) in L T a n d S M , a r e g i v en i n T a b l e s2 a n d 3 . O f t h e s a m p l e s a n a l y s e d , 1 8 w e r e c l a s si f ie d a s D F D ( 5. 7% ) , 2 0 7s l i g h t l y D F D ( 6 6. 3% ) , 8 1 a s n o r m a l ( 2 5 , 9% ) , f iv e s l i g h t ly P S E ( 1.6 % )a n d o n e P S E . T h i s p e r c en t a g e o f P S E o r s li gh t ly P S E m e a t i s w e l l b e lo w t h e3 5 % d e t e c t e d b y O l i v e r e t a l . ( 1 9 8 8 ) i n S p a i n a n d t h e 4 1 % b y K a l l w e i t( 1 9 8 1 ) i n G e r m a n y , b o t h b a s i n g t h e i r r e su l ts o n t h e p H 4 5 v a l u es . N os i g n if i ca n t d if fe r e n c e s c a n b e a p p r e c i a t e d b e t w e e n D F D a n d s l i gh t lyD F D e xc ep t in F O P 2 4 L T , E C 24 S M a n d p H 2 4 i n b o t h m u s c l e s , n o r[ b et w e en P S E a n d s l ig h t l y P S E e x c e p t i n F O P 45 L T a n d E C 4 5 L T . S i m i l a rr e s u l t s w e r e f o u n d f o r t h e e x t r e m e l y P S E a n d P S E c a t e g o r i e s b y O l i v e r


5/10

TABLE2

MeQ

yCaescoDeeQ

yCeenhLMue

DD

SgyDD

Nm

SgyPE

NMe

SD

NMe

SD

NMe

SD

NMe

SD

PE

NMe

SD

pH

1

66~23

2

64b03

8

6004

FO

1

65a

44

2

89a57

8

14b63

E

1

42a51

2

41a09

8

53b18

pH

1

60a02

2

58b01

8

57c02

FO

1

11

61

2

29b77

8

27b91

E

1

36~06

2

38a13

8

51b17

5

55d02

52485

5

9938

5

56d01

5

12~48

5

7616

1

52d

1

40d

1

11d

1

55d

1

30"b

1

17

m m m p

Mewhdeesu

psaesgcydee(P


6/10

4 1 6 M . D . G arr ido , J . P edauyO, S . B a~6n , J . Laenc ina

e t a l . ( 1 9 9 1 ) w h i l e F O P 2 4 a l s o p e r m i t t e d V a n d e r W a l e t a l . (1987) tod i ff e re n t ia t e b e t w e e n b o t h c a te g o r ie s o f D F D a n d P S E .M o s t o f th e m e a n v a l u e s f r o m e a c h p a r a m e t e r s a r e s ig n i fi c an t ly d i f fe r e n tb e t w e e n n o r m a l , P S E a n d D F D . H o w e v e r , t h e F O P v a l u e s f o r n o r m a l

a n d D F D m e a t a r e s o m e t im e s s im i l ar , p a r t i c u l a rl y i n th e c a s e o f FO P4 5,c o i n c i d i n g w i th t h e f in d i n g s o f W a r r is s e t a l . (1989) .T h e p H 4 5 m e a s u r e m e n t p e r m i t s t h e d i f f e re n t ia t io n b e t w e e n n o r m a l a n dP S E , a n d t h e pH 24 p e r m i ts t h e s a m e b e t w e e n n o r m a l a n d D F D , a l t h o u g ht h i s d i f f e r e n c e w a s n o t s i g n i f i c a n t ( P < 0 . 0 5 ) . T h i s i s i n a g r e e m e n t w i t h t h er e s u l t s o f L 6 p e z - B o t e e t a l . (1989) , Wa r r i s s e t a l . ( 1 9 8 9 ) a n d B r o w n( 19 92 ). O n t h e o t h e r h a n d , W H C a n d S P d i s ti n g u is h b e tw e e n P S E a n dD F D b u t n o t b e t w e e n n o r m a l a n d D F D m e a t . S im i la r r es u lt s w e r eo b t a i n e d b y L 6 p e z - B o t e e t a l . (1989) .B o t h O s t e r a n d F e w s o n ( 1 99 0) a n d T r o u t ( 19 92 ) fo u n d t h e L * v a lu e tob e d i ff e r e n t f o r D F D a n d P S E m e a t , a l t h o u g h t h e d i f fe r e n ce s a r e le ss f o rD F D a n d n o r m a l . P i g m e n t c o n t e n t is s li gh tl y d i ff e re n t f o r P S E , n o r m a la n d D F D m e a t , a l t h o u g h n o d if fe re n c es a r e a p p a r e n t f o r m o i s t u r ec o n t e n t a n d i n t r a m u s c u l a r f a t. T r o u t ( 19 9 2) a l so f o u n d d i ff e re n t p i g m e n tc o n c e n t r at io n s i n e x tr e m e ly D F D a n d P S E m e a t.T a b l e s 4 a n d 5 s h o w s t h e c o r r e l a t i o n s b e t w e e n t h e q u a l i t y c h a r a c t e r i s t i c ss t u d i e d i n L T a n d S M r e s p e c t i v e l y . I n g e n e r a l , t h e y a r e l o w . T h i s m a y b ed u e t o t h e s m a ll n u m b e r o f P S E a n d s li gh tl y P S E m e a t s fo u n d , w h i c hw o u l d r e d u c e t h e v a r i a b i li t y o f t h e o v e r a l l s a m p l e . C h i z z o l in i e t a l . (1991)o b t a i n e d s i m i l a r c o r r e l a t i o n s i n S M m u s c l e .T h e r e i s a l o w d e g r e e o f c o r r e l a t i o n , a l t h o u g h s ti ll s ig n i fi c an t ( P < 0 . 0 1 ) ,b e t w e e n F O P a n d E C i n b o t h m u s c l e s s t u d i e d w h i l s t t h e r e i s a b e t t e r c o r -r e l a t i o n f o r p H ( p H a sS M - p H 4 5 L T , r = 0 . 7 4 , P < 0 . 0 0 1 ; p H 2 4 S M - p H z 4 L T ,r = 0 .7 1 P < 0 . 0 0 1 ). E C v a lu e s a r e m o d e r a t e l y c o r r e l a te d w i t h F O P a n d p H .T h e s e r e s u l t s a r e s i m i l a r f o r b o t h m u s c l e s . T h e h i g h e s t c o r r e l a t i o n s a r et h o s e b e t w e e n F O P 4 5 S M - E C 4 5 S M ( r = 0 . 5 6 , P < 0 . 0 0 1 ) a n d b e t w e e n

T A B L E 4C o e f f ic i e n ts o f C o r r e l a t i o n b e t w e e n M e a t Q u a l i t y C h a r a c t e r i s t i c s i n Longissimus thoracis

FOP45 EC45 p ~ t / 4 5 F O P 2 4 E C24 P H 24F O P 4 5E C 4 5 0 " 4 5 "p H 4 5 - 0 " 3 3 "F O P 2 4 0 " 0 1E C e 4 0 . 2 7 "p H 2 4 - 0 . 1 9 b

- 0 " 4 3 "- 0 " 1 0 ' 0 3

0 " 56 " - 0 " 4 5 " 0 " 02- 0 - 1 7 b 0 "5 4" - 0 " 0 8 - 0 . 2 6 aa p < 0 "00 1; b p < 0"0 1 ; P < 0 "05.


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TABLE5

CeaoC

cesbw

MeQ

yCaescnSmmmau

FO

E

pH4FOPE

pH

L

a

b

WH

SPPgmMosuIma

FO E pH FO E PH L a* b

05 -03

-04

03a03

-00

02

03

-04

02

-01

-01~04

-01c-02

00

01

00

01

-00

02b

01-00

00

01

-00

-01~-04

00

00

00

-00

-00

-02b05

-03

WHC

-01b-00

00

-01c00

02a00

-02b01

S

-00

-00

00

-01

00

00

00

-00

02b-00

Pgme

-00

-01

-01

-02

-01

-01

-04a05

-02b

01

00

Mosue

00

-00

-00

-00

00

-00

-01

02c-02

-00

-01-02a

Im.fa

01

01-02a00

02

-01

03

-03

02~-00

00-03

-02b

"P


8/10

418 M . D . G a r r i d o , J . P e d a u y O , S . B a ~ 6 n , J . L a e n c i n a

p H 4 5 S M - E C 4 5 S M ( r = - 0 . 4 8 , P < 0 . 0 0 1 ) , a l t h o u g h t h i s l a t t e r r e l a t i o n s h i p i ss t i l l b e l o w t h a t f o u n d b y O l i v e r e t a l . ( 1 9 9 1 ) ( r = - 0 . 7 ) a n d F i s c h e r a n dH o n i k e l ( 1 9 8 6 ) ( r = - 0 . 8 9 ) .T h e L * a n d a * v a l u e s a r e s l i g h t l y c o r r e l a t e d w i t h p i g m e n t c o n t e n t ,r - - 0 . 4 5 a n d r = 0 . 5 8 , re s p e c ti v e ly . W a r r i s s e t a l . ( 1 9 9 0 ) o b t a i n e d a s i m i l a rc o r r e l a t i o n f o r t h e L * - p i g m e n t ( r = - 0 . 3 4 ) . O n t h e o t h e r h a n d , t h e r e i sh a r d l y a n y r e l a t i o n s h i p b e t w e e n F O P a n d L * , n o r b e t w e e n F O P a n dp i g m e n t c o n t e n t . I n s p it e o f t h is , t h e F O P z 4 - p i g m e n t c o r r e l a t i o n i ss i g n i f i c a n t ( P < 0 . 0 0 1 ) . S i m i l a r r e s u l t s w e r e o b t a i n e d b y S o m e r s e t a l .( 1 9 8 5 ) . H o w e v e r , W a r r i s s e t a l . ( 1 9 8 9 ) f o u n d a c o r r e l a t i o n c o e f f i c i e n t o fr = 0 . 5 0 f o r F O P 4 5 - L * a n d r = 0 . 8 6 f o r F O P 2 4 - L * .

L o w e r o r n o n s i g n i f i c a n t c o r r e l a t i o n s w e r e f o u n d b e t w e e n p i g m e n tc o n t e n t , W H C , s o l u b l e p r o t e i n s o r i n t r a m u s c u l a r f a t . O n l y b e t w e e np i g m e n t s a n d i n t r a m u s c u l a r f a t w a s t h i s c o e f f i c i e n t s l i g h t l y h i g h e r a n dt h e c o e ff ic i en t w a s s i g n i f ic a n t b e t w e e n p H 2 4 - W H C a n d F O P 2 4 - W H C( P < 0 . 0 0 1 a n d P < 0 . 0 5 r e s p e c t i v e l y ) .O f t h e t h r e e p a r a m e t e r s p H , F O P a n d E C , t h e f ir st se e m s t o b e a g o o dp r e d i c t o r o f q u a li t y a t 45 m i n t o d i f fe r en t ia t e b e t w e e n n o r m a l a n d P S Em e a t , a n d a t 2 4 h t o d i f f e r e n t i a t e n o r m a l a n d D F D m e a t . T h e g r e a t e s td i ff er e nc e s i n F O P v a l ue s a r e f o u n d b e t w e e n n o r m a l m e a t a n d m e a t

t e n d i n g t o w a r d s P S E . E C is b e t te r f o r d e te c t in g P S E m e a t .T h e o t h e r p a r a m e t e r s s t u d i e d a l s o p r o v i d e d i n f o r m a t i o n o n m e a t q u a l i t ya l t h o u g h o n l y t h e W H C v a l u e s a n d p i g m e n t c o n t e n t s h o w i m p o r t a n tv a r i a t i o n s a c c o r d i n g t o t h e q u a l i t ie s c a te g o r i e s .I n o r d e r t o d e t e r m i n e t h e r e l a ti o n s h i p b e t w e e n t h e o n - l in e m e a s u r e m e n t su s e d i n b o t h m u s c l e s , a p r i n c i p a l c o m p o n e n t s a n a l y s i s ( P C A ) h a s b e e nc a r r i e d o u t . T h e r e s u l t s s h o w t h a t t h e f i r s t c o m p o n e n t ( P C 1 ) e x p l a i n e d3 4 . 9 % a n d t h e t w o f i r s t c o m p o n e n t s e x p l a i n e d 4 9 . 1 % o f t h e t o t a l v a r i a t i o n .E i g e n v e c t o r s o f e a c h v a r ia b l e f o r t h e t w o P C s a r e s h o w n i n T a b l e 6 .M e a s u r e m e n t s t a k e n a t 4 5 m i n w e r e s l i g h t l y h i g h e r t h a n t h e 2 4 h v a l u e si n P C 1 . T h e m o s t i m p o r t a n t v a r i a b le s i n P C 1 w e r e pH 4 5 a n d E C 4 5. E Ca n d F O P p r e s e n t e d a p o si ti v e c o r r e l a t i o n w i t h P C 1 , w h i le p H s h o w e d an e g a t i v e c o r r e l a t i o n . T h e s a m p l e s a s s u m e d n e g a t i v e v a l u e s i n P C 1 i n t h eD F D - d i r e c t i o n a n d p o s i t i v e i n t h e P S E - d i r e c t i o n . W h e n t h e D F D i n t e r v a li n PC 1 w a s s t u d ie d , t h e 1 8 l o w e s t v a l u es c o r r e s p o n d e d t o 8 D F D a n d1 0 s l ig h t ly D F D s a m p l e s . W h e n t h e n e x t 2 08 s a m p l e s w e r e t a k e n i n t oa c c o u n t , s a m p l e d i s t r i b u t i o n s i n P C 1 w e r e : 10 D F D , 1 76 s li g h tl y D F Da n d 2 2 n o r m a l . A s c a n b e s e e n , P C 1 w a s n o t a g r e a t v a l u e f o r i d e n t i f y i n gD F D m e a t s . W h e n t h e P S E i n t e r v a l i n P C 1 w a s s tu d i e d , t h e g r e a te s tv a l u e c o r r e s p o n d e d t o t h e P S E s a m p l e . T h e n e x t f i v e g r e a t e r v a l u e sc o r r e s p o n d e d t o s l i g h t l y P S E s a m p l e s . P C 1 , t h e n . i s a v a r i a b l e w h i c h c a nb e u s e d t o d e t e c t P S E m e a t s , a l t h o u g h , t h e l o w n u m b e r o f c a rc a ss e s


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Objec t ive assessmen t o f po rk qua l i ty 41 9

T A B L E 6Coefficients in the Eigenvectors for the tw o First Principal Co mpo nentsVa r ia b l e P C 1 P C 2

FOP45 SM 0.26 0.33FOP45 L D 0.27 0-21FOP24 SM 0.17 0-42FOP24 L D 0.03 0.20EC45 SM 0.34 0-35EC45 L D 0-31 0.22EC24 SM 0-24 0-01EC24 L D 0.30 0.02pH45 SM -0 . 40 0-21pH45 LD -0 .3 8 0-25pH24 SM -0 .2 8 0-40pH24 LD -0-29 0-43

c l a s si fi e d a s P S E a n d s l ig h t ly P S E m a k e s i t d i ff ic u lt t o d r a w a n y c o n c l u -s i o n i n t h i s r e s p e c t .

I n b o t h P C 1 a n d P C 2 , p H h a d t h e h ig h e s t l o a d in g , w h i c h s h o w s th ev a l u e o f th is p a r a m e t e r a s a p r e d i c t o r o f m e a t q u a l it y .

R E F E R E N C E SB ar t o n - G ad e , P . ( 1 9 8 0 ) . M an u s c r i p t 6 0 6 E , S l ag t e r i e r n e s F o r s k n i n g s i n s t i t u t ,D e n m a r k .B a r t o n - G ad e , P . ( 1 9 9 1 ) . S e p o r . L o r ca , E s p a f i a .Bendal l , J . R . & Lawr ie , R . A . (1964) . A n i t a . B r . A b s t r . , 32, 1.Brown , S . N. (1992) . M e a t S c i . , 32, 195.Ch izzo l in i , R . , Delbono , G . , Novel l i , E . , Pongo l in i , S . & Rosa , P . (1991) . 3 7 t hI C o M S T . K u l m b a c h , G e r m a n y .De V r i e s , A . G . , W a l , P . G . v an d e r & M er k s , J . W . M . ( 1 9 9 0 ) . V e r s l ag en v and e c o n t a c t d a g N a a r d e n v le ze . D i e n s t L a n d b o u w k u n d i g O n d e r z o e k . E d e .E i k e l en b o o m , G . , Ho v i n g - B o l i n k , A . H . & Hu l s eg g e , B . ( 1 9 9 2 a ) . M e a t S c i . , 31 ,343.Eike l enboom, G . , Zhang , W. , Hov ing-Bo l ink , A . H. , Gar ssen , G . J . & S te r r enburg ,P. (1992b) . 3 8t h I C o M S T . C l e r m o n t - F e r r a n d , F r a n c e .El l io t , R . J . (1969) . J . F o o d T e c h n o l . , 4, 147.F i scher , K. & Hon ike l , K. O. (1986) . P r o c . C E C W o r k s h o p : O n L i n e a n d N o n -d e s tr u c ti v e M e t h o d s t o M e a s u r e M e a t C h a ra c te r is ti cs , T h e N , F r a n c e .Gar r ido , M. D. , Pedauy6 , J . , Baf idn , S . , P6rez , A . D. & Laenc ina , J . (1992) . 3 8 t hI C o M S T . C l e r m o n t - F e r r a n d , F r a n c e .G r a u , R . & H a m m , R . ( 1 9 5 3 ) . N a t u r w i s s . , 40, 29 .ISO S tandard 1443 (1973) . M e a t a n d M e a t P r o d uc ts .


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420 M. D. Garrido, J. Pedauy~, S. Ba~6n, J. LaencinaIS O S t an d a rd 1 4 4 2 (19 73 ). Meat and Meat Products.Kallwei t , E. (1981). Proc. Porcine Stress and Meat Quality Causes and PossibleSolutions to the Problems, ed . T . F roys te in , E . Sh ide & N. S tanda l , p .75 .K au f f m an , R . G . , E i k e l en b o o m , G . , W a l , P . G . v an d e r & Merk u s , G . (1 9 8 6 ) .Meat Sci., 18, 191.L6pez-Bo te , C . , Warr i s s , P . D . & Brown, S . N . (1989) . Meat Sci. 26, 167.MacDougal l , D . B . (1984) . Proc. Sci. Meeting Biophysical PSE-Muscle Analysis,V i en n a .MacDougal l , D . B . & Disney , J . G . (1967) . J. Food Technol., 2, 285.M acD o u g a l l , D . B . , C u t h b e r t s o n , A . & S m i th , R . J . ( 19 69 ). Anim. Prod., 11, 243.Ol iver , M. A. , Gisper t , M. & Dies t re , A . (1988) . Med. Vet.,5, 45.Ol iver , M. A. , Gisper t , M. , T ibau , J . & Dies t re , A . (1991) . Meat Sci. 29, 141.O s t e r , A . v o n & F ew s o n , D . (1 9 9 0 ) . Ziichtungskunde, 62, 141.Somers , C . , Tar ran t , P . V. & Sher ing ton , J . (1985) . Meat Sci., 15, 63.Trou t , G . R . (1991) . 37th ICo MST, K u l m b a c h , G e r m a n y .Trou t , G . R . (1992) . 38th ICo MST, C l e r m o n t - F e r r a n d , F r a n c e .Wal , P , G. van der , N i jeboer , H . , Merkus , G. S . M. (1987) . In Evaluation andControl of Meat Quality in Pigs, ed . P . V . Ta r r an t , G . E i k e l en b o o m & G .M o n i n . M a r t i n u s N i jh o f f, D o r d r e c h t .W al , P . G. van der , O lsm an , W. J ., Garssen , G. J . & Engel , B . (1992) . MeatSci., 32, 351.Warr i s s , P . D . , Brown , S . N . , L6pez-Bo te , C . , Bev is , E . A. & Adamns , S . J . M.(1989). Meat Sci., 25, 281.W arr i s s , P . D . , Brow n , S . N . & A dam s , S . J . M . (1990) . Meat Sci., 28, 321.W isme r-Ped ersen , J . (1959). Food Res., 24, 711.

Objective Assessment of Pork Quality

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