estabilidade oleo soja e canola na composição de ácidos graxos

7/28/2019 estabilidade oleo soja e canola na composio de cidos graxos

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Frying Stabi li ty of Soyb ean and C anola O i ls with M odified Fa t tyAcid Composit ionsK . W a r n e r * a n d T .L . M o u n t sFood Qua l i ty and S afety Research, NCA UR, ARS, USDA, Peoria, i ll ino is 61604

98 3

P i l o t p l a n t - p r o c e s s e d s a m p l e s o f s o y b e a n a n d c a n o l a I lo w -e r u c i c a c id r a p e se e d ) o i l w i t h f a t t y a c i d c o m p o s i t i o n sm o d i f i e d b y m u t a t i o n b r e e d i n g a n d/ or h y d r o g e n a t i o n w e r ee v a l u a t e d f o r f r y i n g s t a b i li t y . L i n o l e n i c a c i d c o n t e n t sw e r e 6 . 2% f o r s t a n d a r d s o y b e a n o i l , 3 .7 % f o r l o w - l i n o l e n i cs o y b e a n o i l a n d 0 . 4 % f o r t h e h y d r o g e n a t e d l o w - l i n o l e n i cs o y b e a n o i l . T h e l i n o l e n i c a c i d c o n t e n t s w e r e 1 0 .1 % f o rs t a n d a r d c a n o l a o i l, 1.7 % f o r c a n o l a m o d i f i e d b y b r e e d i n ga n d 0 .8 % a n d 0 .6 % f o r o i ls m o d i f i e d b y b r e e d i n g a n dh y d r o g e n a t i o n . A l l m o d i f i ed o i ls h a d s i g n i f i c a n t l y ( P


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98 4K . W A R N E R A N D T . L . M O U N T S

Oil characterization. F a t t y a c i d c o m p o s i t i o n s o f t h e i ni -t i al o i ls w e re d e t e r m i n e d b y c a p i l l a r y g a s c h r o m a t o g r a p h i c( G C ) a n a l y s i s w i t h a V a r i a n 3 4 0 0 G C ( P a lo A l t o , C A ) e q u ip -p e d w i t h a S P 2 3 3 0 c o l u m n ( 3 0 m , 0 . 2 5 m m i . d . , 0 . 2 0 t ~ mf i l m t h i c k n e s s ) ( S u p e lc o , B e l l e fo n t e , P A ) . A f t e r s a m p l e i n -j e c ti o n , t h e c o l u m n t e m p e r a t u r e w a s h e l d a t 1 7 0 C f o r 1 0m i n . T h e t e m p e r a t u r e w a s p r o g r a m m e d t o i n c r e as e a t3 C / m i n t o 2 2 0 C , w i t h a f i n a l h o l d o f 1 0 m i n . F r e e f a t t ya c i d (F F A} c o n t e n t s w e r e m e a s u r e d i n d u p l i c a t e b y t h eA O C S M e t h o d C a 5 a - 40 ( 1 5} . T h e p e r c e n t p o l a r c o m -p o u n d s w e r e d e t e r m i n e d i n d u p l i c a t e b y t h e A s s o c i a t i o no f O f f ic i al A n a l y t i c a l C h e m i s t s ' c o l u m n c h r o m a t o g r a p h ym e t h o d ( 16 ). F o a m h e i g h t ( in c m ) w a s m e a s u r e d i nd u p l i c a t e i n t h e f r y e r s a f t e r 1 0 , 20 , 3 0 a n d 4 0 h o f h e a t i n ga n d f r y i n g a t 1 9 0 C . A 1 5 - cm s t a i n le s s - s te e l m e a s u r e w i t h1 0 - m m g r a d a t i o n s w a s h e l d i n t h e c e n t e r o f th e f r y e r, a n da r e a d i n g w a s t a k e n 3 0 s a f t e r a 1 5 0 - g b a t c h o f f r e s hs h o e s t r i n g p o t a t o e s w a s p l a c e d i n t h e f r ye r . T h e h e i g h to f o il p r i o r t o e a c h f r y i n g w a s s u b t r a c t e d f r o m t h em e a s u r e m e n t t o d e t e rm i n e e x a c t f o a m h e ig h t .Statistical analysis. D a t a w e r e i n t e r p r e t e d b y a n a l y s iso f v a r i a n c e ( 17 ). S t a t i s t i c a l s i g n i f i c a n c e w a s e x p r e s s e d a tt h e P < 0 . 05 l e v e l u n l e s s o t h e r w i s e i n d i c a t e d .

T A B L E 2F a t t y A c i d C o m p o s i t io n o f C a n o la O i l saF a t ty ac id Oi lscomposition CAO b L o L n~ Lo Lnd-Br H yd Lo Ln~-HydC16:0 4.3 5.1 5.3 5.3C18:0 1.7 1.9 2.6 5.1C18:l-cis 60.5 65.6 69.0 39.7C18:l-trans 3.9 46.6C18:2-cis 20.8 24.0 16.5 0.5C18:2-trans 0.3 1.1C18:3 10.1 1.7 0.8 0.7C20:1 1.3 0.8 0.8 0.6C22:1 0.5 0 0 0Iodin e value 114 91 91 77aLow-erucic acid rapeseed oil.bStandard canola oil.CLow-linolenic acid cano la oil.dBrush hydrogen ated, low-l inolenic acid canola oi l .~Hydrogenated low-linolenic acid canola oil.

R E S U LT S A N D D I S C U S S I O NFatty acid composition. T h e f a t t y a c id c o m p o s i t io n o f t h eS B O s s h o w e d a r a n g e o f i o d i n e v a l u e s f r o m 1 3 1 f o r S B Ot o 9 2 f o r a n o i l m o d i f i e d b y b r e e d i n g t o a L n c o n t e n t o f3 .7 ( L o L n ), f o l lo w e d b y h y d r o g e n a t i o n t o a L n v a l u e o f0 .4 ( L o L n - H y d ) ( T a b le 1). T h e S B O h a d a 6 .2 % L n c o n t e n t .T h e C A O s r a n g e d i n io d i n e v a l u e f r o m 1 1 4 f o r C A O t o7 7 f o r a n o i l m o d i f i e d t o a L n l e v e l o f 1. 7% ( L o L n ), w i t ha f u r t h e r r e d u c t i o n i n L n t o 0 .7 % ( Lo L n - H y d ) b yh y d r o g e n a t i o n ( T a bl e 2 ). A b r u s h h y d r o g e n a t i o n p r o c e s sd e c r e a s e d t h e L o L n s a m p l e f r o m 1 .7 t o 0 .8 % L n ( L o L n -B r H y d ) . B y t h e s e p r o c e d u r e s , trans C 1 8 : 3 w a s n o td e t e c t e d i n a n y o f t h e o i ls .Oil deterioration mea sureme nts. F F A s , w h i c h m e a s u r eo i l h y d r o l y s i s , in c r e a s e d i n t h e S B O s w i t h i n c r e a s i n g o i lu s a g e a s e x p e c t e d ( F i g. 1 ). T h e S B O h a d t h e h i g h e s t F F Al ev e ls , f o l lo w e d b y t h e L o L n - H y d s o y a n d t h e L o L n s o y .T h e F F A v a l u e s a f t e r 4 5 h o f h e a t i n g a n d f r y i n g w e r e 0 .2 4f o r s o y , 0 . 2 3 f o r L o L n - H y d s o y a n d 0 . 2 1 f o r L o L n s o y .

T A B L E 1F a t t y A c i d C o m p o s i t i o n o f S o y b e a n O i l sFa tty acid Oilscomposi t ion SBOa Lo Ln b Lo LnC-HydC16:0 11.4 11.4 9.9C18:0 3.9 4.4 4.0C18:l-cis 24.2 25.0 48.1C18:l-trans 16.3C18:2-cis 54.4 55.3 17.6C18:2-trans 3.0C18:3 6.2 3.7 0.4Iodin e valu e 131 126 92"S tandard soybean o i l.bLow-linolenic acid soyb ean oil.CHydrogenated, low-linolenic acid soybean oil.

T h e F F A l e v el s i n t h e C A O s s h o w e d n o s i g n i f i c a n t d i f-f e r en c e s b e t w e e n t h e L o L n a n d t h e L o L n - B r H y d C A O sa t a n y o f t h e e v a l u a t i o n t i m e s ( F ig . 1 }. T h e F F A l e v e ls int h e C A O a n d L o L n - H y d o il s w e r e s ig n i f i c a n tl y h i g h e rt h a n t h e o t h e r t w o C A O s . A f t e r 4 5 h o f u s a g e , o il s h a dF F A o f .3 4 f o r L o L n ; .3 7 f o r L o L n - B r H y d ; .4 8 f o r L oL n - H y d ; a n d . 6 6 fo r C AO .T h e d e c r e a s e d l ev e l s o f L n i n t h e m o d i f i e d S B O sr e s u l t i n g f r o m e i t h e r b r e e d i n g o r b r e e d i n g / h y d r o g e n a t i o nh e l p e d c o n t r i b u t e t o s i g n i f i c a n t l y l o w e r a m o u n t s o f p o l a rc o m p o u n d s c o m p a r e d t o t h e S B O ( F ig . 2). T h e S B O

0 .250 .2

0 .15~ o.10

o.o5'"o 0.0.mO< 0.6

0.5u_ 0.4

0 .3u_ 0.2

0.11

-O- SoybeanLo Ln

-l - Lo Ln--Hyd. ~/ -

S f .~ -, i i i i

-e- CanolaLo Ln

"-#-- LO Ln-- Br. Hyd, ~ .. .-Lo Ln--Hyd. ~ . " " " -

. . . . n ' ' " ~ 1 4 ,

;--222 - - - - ~; t ; d 5 4 5

H o u r s o f F r y i n g a n d H e a t i n g a t 1 9 0 CF I G . 1 . F r e e f a t t y a c i d s i n s o y b e a n a n d c a n o l a o i l s . L o L n , l o wl ino len ic ; Lo Ln-Hyd, low l ino len ic , hydrogenated; Lo Ln-Br Hyd,l o w l i n o le n i c , b r u s h h y d r o g e n a t e d .

JAOCS, Vol. 70, no. 10 (October 1993)


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FRYING ST ABILITY OF SOYBEAN AND CANOLA OILS98 5

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5 1 5 2 5 3 5 4 5

H o u r s o f F r y i n g a n d H e a t i n g a t 1 9 0 CFIG. 2. P e r c e n ta g e p o l a r c o m p o u n d s i n s o y b e a n a n d c a n o l a o i l s. S e eF igure 1 for abbrev ia t ions .

c o n t a i n e d 4 2 % p o l a r c o m p o u n d s a f t e r 4 5 h o f h e a t i n g a n df r y in g , w h e r e a s b o t h m o d i f i ed S B O s o n l y h a d 2 5 % p o l a rc o m p o u n d s . A s t a n d a r d l e v e l o f 2 7 % p o l a r c o m p o u n d s i su s e d i n E u r o p e t o i n d i c a t e s e v e r e l y d e t e r i o r a t e d o il. T h eS D f o r p o l a r c o m p o u n d s i n t h e s o y b e a n v a r i e t i e s r a n g e df r o m 0 t o 1 .6 w i t h a n a v e r a g e d e v i a t i o n o f 0 .9 .T h e a m o u n t o f p o l a r c o m p o u n d s f o r m e d i n t h e m o d i f ie dC A O s a n d C A O w e r e si m i l a r a t a l l e v a l u a t i o n t i m e s( a v e r a g e S D - - 0 . 7) (F i g . 2). T h e L o L n C A O h a d t h e l e a s ta m o u n t o f p o l a r c o m p o u n d s o f a ll t h e C A O s a t e a c h f ry -i n g t i m e ; h o w e ve r , t h e l e v e ls w e re h i g h - - 2 7 % - - e v e n a f t e ro n l y 2 5 h o f o il u s a g e .I t i s w e l l k n o w n t h a t u n s a t u r a t e d f a t t y a c i ds a r e m o r es u s c e p ti b l e t h a n s a t u r a t e d o n e s t o o x y g e n a t t a c k d u r i n gt h e r m a l o x i d a t i o n , a n d t h i s c a n r e s u l t i n h i g h e r l e v el s o fp o l a r c o m p o u n d s . T h e r e f o r ~ t h e l ev e l o f p o l a r c o m p o u n d si n t h e f r y i n g o i ls s h o u l d b e r e l a t e d t o t h e d e g r e e o f u n -s a t u r a t i o n o f th e o il . H o w e v e r , p r e v i o u s r e p o r t s i n t h el i t e r a t u r e a r e n o t c o n s i s t e n t i n f i n d i n g h i g h c o r r e l a t i o n so f u n s a t u r a t i o n a n d p o l a r c o m p o u n d s . D o b a r g a n e s a n dP e r e z - C a m i n o (1 8) r e p o r t e d a t r e n d t o w a r d h i g h e r p o l a rc o m p o u n d s a s u n s a t u r a t i o n i n c re a s e s. I n t h e i r st u d y , p a l mo il w i t h 5 6 % u n s a t u r a t e s w a s h e a t e d f o r 1 0 0 h a t 1 9 5 Ca n d h a d a p o l a r c o m p o u n d l e v e l o f 5 8% . O l i v e oi l w i t h 8 6 %u n s a t u r a t i o n w a s t r e a t e d u n d e r t h e s a m e c o n d i t io n s a n dh a d a p o l a r c o n t e n t o f 6 6% . O n t h e o t h e r h a n d , t h e y f o u n dt h a t o l i v e o il a n d S B O w i t h s i m i l ar u n s a t u r a t i o n ( 86 % )h a d p o l a r c o m p o u n d s o f 66 a n d 7 1% , r e s p e c ti v e l y . S e b e d i oa n d c o - w o r k e rs (1 9) f o u n d s i m i la r r e s u l t s f o r p e a n u t a n dS B O s . T h e y r e p o r t e d t h a t t h e p e r c e n t a g e s o f p ol a r c om -p o u n d s i n t h e o i ls w e re e q u i v a l e n t a f t e r u p t o 3 0 h o f f r y -i n g f r e n c h f ri es . W o r k b y C h u ( 20 ) s u p p o r t s t h e f i n d i n g st h a t u n s a t u r a t i o n i s n o t a l w a y s a g o o d p r e d i c t o r o f p o l a rc o m p o u n d f o r m a t i o n . I n t h a t s t u d y , a b l e n d o f p a l mo l e i n : S B O w i t h a n i o d i n e v a l u e ( I V ) o f 1 0 1 a n d as e s a m e : S B O b l e n d w i t h a n I V o f 1 2 2 w e r e u s e d f o rf r y i n g f o r 1 6 h . T o t a l p o l a r c o m p o u n d s i n t h e b l e n d s w e r e

s i m i l a r a t 1 4 a n d 1 5 % , r e s p e c t i v e l y . I n t h i s p r e s e n t s t u d y ,b o t h t h e L o L n S B O a n d L o L n - H y d S B O h a d s ig n if i-c a n t l y l e ss t o t a l p o l a r c o m p o u n d s t h a n S B O o r a n y o f t h eC A O s a f t e r 1 5 t o 4 5 h o f h e a t i n g a n d f r y i n g . W e o b s e r v e dt h e s e r e s u l t s ev e n t h o u g h t h e t h r e e S B O s h a d s i m i l a rl e ve l s o f u n s a t u r a t i o n ( 8 4 -8 5 % ) . U n s a t u r a t i o n o f t h e o i li s p r o b a b l y o n l y o n e o f m a n y c o m p o s i t i o n a l f a c t o r s a ff e ct -i n g t h e f o r m a t i o n o f t o t a l p o l a r c o m p o u n d s .T h e a m o u n t o f f o a m i n g i n a u s e d f r y i n g o il i s a n o t h e rm e a s u r e o f fa t d e t e r i o r a t i o n . T h e v a l u e s in t h i s s t u d yr e p r e s e n t t h e l e ve l o f f o a m a b o v e t h e s u r f a c e o f t h e o i l a sf r e s h p o t a t o e s w e r e f ri e d. T h e r e w e r e n o s i g n i f i c a n t d i f-f e r e n c e s b e t w e e n t h e t w o m o d i f i e d S B O s ; h o w e v e r, t h eS B O h a d s i g n i f i c a n t l y h i g h e r f o a m h e i g h t t h a n t h e o t h e rt w o o i l s a t t h e 2 0 - , 3 0 - a n d 4 0 - h t e s t i n g p e r i o d s ( F i g . 3 } .I n a d d i t i o n , t h e f o a m h e i g h t i n t h e m o d i f i e d S B O s w a sl e ss t h a n 1 .0 c m a t e v e r y s a m p l i n g t im e .T h e v a r i a t i o n s i n f o a m h e i g h t s o f C A O s w e r e n o ts i g n i f i c a n t l y d i f f e r e n t u n t i l 2 0 h o f o il u s a g e ( F i g. 3 ). T h eC A O h a d s i g n i f i ca n t ly m o r e f o a m d e v e l o p m e n t t h a n t h em o d i f i e d C A O s a t t h e 2 0 - , 3 0 - a n d 4 0 - h t i m e s .

F o a m h e i g h t m e a s u r e m e n t w a s t h e m o s t s e n s it iv e t e s tf o r d i f fe r e n c e s b e t w e e n m o d i f i e d a n d u n m o d i f i e d o i ls o fb o t h o i l t y p e s . P o l a r - c o m p o u n d a n a l y s i s w a s s e n s i t i v e t ot h e d i f f er e n c e s i n m o d i f i c a t i o n in S B O b u t n o t C A O ,w h e r e a s F F A w a s a b e t t e r i n d i c a t o r o f d if f e r e n ce s f o rC A O s t h a n f o r S B O s .Room odor. T h e o v e r a ll r o o m o d o r i n t e n s i t i e s o f t h eS B O s s h o w e d t h a t r e d u c i n g t h e L n c o n t e n t t o 3 .7 %s i g n i f i c a n t l y d e c r e a s e d t h e o d o r s c o r e a t a l l e v a l u a t i o nt i m e s c o m p a r e d t o th e s t a n d a r d S B O w i t h 6 .2 % L n( T a bl e 3 ). T h e o v e r a l l o d o r i n t e n s i t y f o r t h e L o L n - H y d s o ys a m p l e w a s s i g n i f i c a n t l y l e ss t h a n t h e S B O a f t e r o n l y t h e1- a n d 1 0 -h t e s t i n g p e r i o d s , b u t s i g n i f i c a n t ly s t r o n g e r t h a nt h e L o L n s o y o ff a t a l l t i m e s e x c e p t t h e l - h t e s t. T h e f i s h y

o d o r , w h i c h i s c h a r a c t e r i s t i c o f h e a t e d l i n o l e n a t e - c o n t a i n -i n g o i l s , w a s p r e s e n t i n a l l t h r e e o i l s f o r t h e i n i t i a l l - h

5 ~ SoybeanLo Ln4 ~ Lo Ln--Hyd.

3

0v 1 --=1 . . . . . . . . . . . . .0 - - - - - - ~ - - "- ~ - " - . . . . . " . . . . . . . . . '

" 1 - CanolaE 5 ~ Lo LnLo Ln--Br. Hyd,

I J- kO kn--Hyd. .43 t I -f .. 42 f ~ I I

1 ~ . ~ ~ - Io10 20 30 40

H o u r s o f F r y i n g a n d H e a t i n g a t 1 9 0 CF I G . 3 . F o a m h e i g h t s i n s o y b e a n a n d c a n o l a o i ls . S e e F i g u r e 1 f o ra b b r e v i a t i o n s .

JAOCS, Vo l . 70 , no . 10 (October 1993)


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986K . W A R N E R A N D ~ L . M O U N T S

T A B L E 3S e n s o r y A n a l y s e s o f S o y b e a n O i l s a n d F o o d F r i e d i n S o y b e a n O i l s

AnalysesHea t / f r y Room odora Fishy odorb Frenc h fr ies cOils at 190 C (h) inte nsit y scores inte nsity scores qua lity scores

Soybean 1 6.6 2.8 - -10 6.2 1.0 5.820 6.1 0.5 5.930 5.8 0.7 6.140 5.8 0.8 5.9

L oL n 1 5.1 0.3 - -10 4.2 0.5 7.420 4.5 0.7 7.230 4.1 0.6 7.140 4.2 0.8 6.9Lo Ln - H yd 1 5 . 6 1 .7 - -10 5.2 0.2 7.020 5.5 0.0 6.930 5.8 0.1 6.840 5.9 0.0 6.7aRoom odor intens i ty: 0 - - none; 10 = s trong.bFishy odor (of fryin g oils) intens ity: 0 = none; 10 -- stron g.CFrench-fried po tato quality: 10 -- excellent; 1 -- bad; L SD = 1.0 (P < 0.05). See Table 1for abbreviat ions .

e v a l u a t i o n b u t w a s s i g n i fi c a n t ly l o w e r i n t h e L o L n s a m -p l e ( T ab l e 3 ). T h e i n t e n s i t y o f t h i s o d o r d e c r e a s e d i n t h eS B O a s h e a t i n g a n d f r y i n g t i m e i n c r e a se d a n d d i s a p -p e a r e d i n t h e L o L n - H y d s o y s a m p l e a f t e r 20 a n d 4 0 ho f h e a t i n g a n d f r y in g . T h e f i s h y o d o r i n t e n s i t y i n c r ea s e ds l i g h t l y in t h e L o L n S B O a s f r y i n g t i m e i n cr e a s ed . O t h e ro f f -o d o r s c o n t r i b u t i n g t o t h e o v e r a l l o d o r i n t e n s i t y w e r ea c r i d in a l l o i ls a n d h y d r o g e n a t i o n i n th e L o L n - H y d o i l.T h e S B O h a d h i g h i n t e n s i t y l e v e ls o f a c r i d o do r , r a n g i n gf r o m 2 .9 f o r t h e 1 - h s a m p l e t o 2 . 0 f o r t h e 4 0 - h o il . T h e L oL n a n d L o L n - H y d S B O s h a d i n i ti a l a c r id s c o r e s o f 1.6a n d 1 .3 , r e s p e c t i v e l y . T h e s e v a l u e s d e c r e a s e d s l i g h t l y o v e rt h e 4 0 - h t e s t . T h e h y d r o g e n a t i o n o d o r i n c r e a s e d w i t h i n -c r e a s e d h e a t i n g a n d f r y i n g o f t h e L o L n - H y d f r o m a lo wo f 1. 9 a t 1 h t o a h i g h o f 3 .4 a f t e r 4 0 h , b u t w a s n o t p r e s -e n t i n e i t h e r t h e S B O o r t h e L o L n S B O .T h e C A O h a d s i g n i f i c a n t l y m o r e o v e r a ll r o o m o d o r i n-t e n s i t y t h a n t h e m o d i f ie d C A O s o n l y a t t h e i n i t ia l 1 he v a l u a t i o n p e r i o d ( T a b l e 4 ). I n s u b s e q u e n t t e s t s a t 1 0 , 2 0 ,3 0 a n d 4 0 h , n o s i g n i f i c a n t d i f fe r e n c e s w e r e n o t e d . T h eo f f -o d o r s i n th e u n m o d i f i e d o i l w e r e p r e d o m i n a n t l y f i s h ya n d a c r id . T h e f i s h y o d o r i n t e n s i t y i n t h e C A O w a s s i g -n i f i c a n tl y h i g h e r t h a n i n t h e o t h e r C A O s a m p l e s a t 1 a n d1 0 h (T a b le 4). T h e a c r i d r a t i n g s f o r t h e C A O r a n g e d f r o m2 .4 f o r t h e 1 -h s a m p l e t o 3 .0 f o r t h e 4 0 - h o il . T h e f i s h y o d o ri n t e n s i t y o f t h e h y d r o g e n a t e d o il s i n c r e a se d s l i g h t ly o v e rt i m e - - 0 . 1 t o 0 .6 . T h e L o L n C A O h a d l o w l e v el s o f f i s h yo d o r i n t e n s i t y ( 0 .5 - 1. 2) a t a l l e v a l u a t i o n t i m e s . H y d r o g e n a -t i o n o d o r w a s p r e s e n t i n b o t h t h e L o L n B r H y d C A O a n dt h e L o L n H y d C A O b u t n o t i n t h e C A O o r t h e L o L n C A O.F r i e d f o o d . T h e q u a l i t y o f f r e n c h f r ie s f ri e d i n b o t h o ft h e m o d i f i e d S B O s w e r e s i g n i f ic a n t l y b e t t e r t h a n t h ep o t a t o e s f r i e d i n t h e S B O { T ab le 3 ). T h e p o t a t o e s f r i e d int h e S B O h a d l e ss f ri e d -f o o d a n d p o t a t o f l a v o rs a n ds t r o n g e r f i sh y f l a v o r t h a n t h e p o t a t o e s f r i e d i n t h e m o d i -f i e d o t is . I n t h e S B O f r e n c h f r ie s , t h e f i s h y f l a v o r i n t e n s i t yw a s h i g h e s t a t 1 0 h w i t h a s c o r e o f 2 .0 , w h i c h d e c r e a s e d

t o 0 .5 a f t e r 4 0 h . B o t h m o d i f i e d o i l s p r o d u c e d f r e n ch f r i e sw i t h s l i g h t { 0 .2 ) t o n o f i s h y f la v o r . P o t a t o e s f r i e d i n L oL n - H y d S B O h a d a s l ig h t h y d r o g e n a t i o n f l av o r a t a l l f ry -i n g t i m e s .T h e q u a l i t y o f t h e f r e n c h f r i e s i n a ll m o d i f i e d C A D s w e r es i g n i f i c a n t l y b e t t e r t h a n t h o s e f r i e d i n C A O ( T a b le 4). T h ep o t a t o e s f r i e d i n C A O h a d s t r o n g e r f l a v o r i n t e n s i t i e s o ff i s h y t h a n t h e p o t a t o e s f r i e d in t h e m o d i f i e d o ti s. T h i s f i n -d i n g i s i n c o n t r a s t t o t h a t o f D o b b s et al . (2 ) w h o r e p o r t e dt h a t t h e f i s h y o d o r o f C A O d i d n o t t r a n s f e r t o th e f l a v o ro f d o n u t s f r ie d in t h e s a m e o il . T h e p o t a t o e s f r i e d i n t h eh y d r o g e n a t e d o i ls h a d a s l i g h t h y d r o g e n a t i o n f la v o r.Cha racte rist ic odors~flavors. I n t r o d u c t i o n o f t h e s e n e w l ym o d i f i e d o i ls a s f r y i n g o i ls h a s g e n e r a t e d i n t e r e s t i n t h et y p e s o f o d o r s a n d f l a v o r s c h a r a c t e r i s t i c o f t h e o i l s a n dt h e r e s u l t i n g f r i e d f o o d s . S t a n d a r d s o y a n d c a n o l a o il o d o r sf o r m e d d u r i n g h i g h - t e m p e r a t u r e h e a t i n g - - a c r i d , f i sh y ,b u r n t a n d r u b b e r y - - a r e c h a r a c t e r i st i c o f a n y L n - c o n ta i n -i n g o i l ( T a b l e 5 ). A s t h e L n c o n t e n t i s d e c r e a s e d , t h e f i s h yo d o r i s l es s ev i d e n t, a l t h o u g h t h e r u b b e r y o d o r m a y s t il lb e d e t e c t e d . P r e d o m i n a n t o d o r s i n t h e L o L n o ti s, m o d i f i e db y b r e e d i n g o n l y , w e r e f r i e d f o o d a n d a c r i d . U s e o fh y d r o g e n a t i o n t o f u r t h e r re d u c e L n c o n t e n t p r o d u c e dh y d r o g e n a t i o n o d o r s a n d f l a v or s , a l t h o u g h a t le s s i n t e n s el e v e ls t h a n f o u n d i n o il s h y d r o g e n a t e d f r o m 8 % L n ( 4). T h eh y d r o g e n a t i o n o f f- o d o r w a s s t il l d e t e c ta b l e , e v e n w h e n t h ei n i t ia l L n c o n t e n t o f t h e o i l t o b e h y d r o g e n a t e d w a s 1 .7 % .I n s u m m a r y , m o s t s e n s o r y a n d p h y s i c a l / c h e m i ca l an a l y -s e s s h o w e d t h a t t h e q u a l i t y a n d s t a b i l i t y o f L o L n S B Ow e r e e q u a l t o th e L o L n - H y d S B O . B o t h m o d i f i e d S B O sw e r e b e t t e r t h a n t h e S B O i n a ll t e s t s ( T ab l e 6 ). T h e L oL n C A O w a s s i g n i fi c a n t l y b e t t e r t h a n t h e h y d r o g e n a t e dL o L n C A O s f o r o n l y p o l a r c o m p o u n d s ( T ab l e 6 ). A l lm o d i f i e d C A O s h a d b e t t e r q u a l i t y a n d s t a b i l i t y t h a n t h eC A O i n a l l a n a l y s e s e x c e p t p o l a r c o m p o u n d s .

M o d i f i c a ti o n o f f a t t y a c id c o m p o s i t i o n b y b r e e d i n g t or e d u c e t h e L n c o n t e n t p r o d u c e d s o y a n d c a n o l a o il s o fJAOCS, VoI. 70, no. 10 (October 1993)


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FRYING STABILITY OF SOYBEAN AND CANOLA OILS

TABLE 4S e n s o r y A n a l y s e s o f C a n o l a O i l s a n d F o o d F r i e d in C a n o l a Oils

AnalysesHeat/fry Room odora Fishy odor b French friescOils at 190C (h) inte nsit y scores intens ity scores quality scores

Canola 1 7.0 2.9 --10 6.3 1.6 3.420 6.2 1.6 4.830 6.1 1.5 4.040 5.7 0.5 5.3

Lo Ln 1 5.9 1.0 --10 5.7 0.5 6.620 5.6 0.9 6.730 5.3 1.2 6.940 5.4 0.9 6.7Lo Ln-Br Hyd 1 6.0 0.1 --10 6.2 0.6 6.720 5.6 0.3 6.430 5.4 0.5 7.140 5.1 0.6 7.0Lo Ln- Hyd 1 6.0 0.1 --

10 6.3 O.6 7.120 5.7 0.2 6.730 5.5 0.3 6.440 5.4 0.4 6.4aRoom odor intensity: 0 = none; 10 = strong .bFishy odor (of frying oils) intensity: 0 = none; 10 -- s trong.CFrench-fried pot ato qu ality: 10 = excellent ; 1 = bad. LSD = 1.0 (P < 0.05). See Table 2for abbreviations.

987

TABLE 5C h a r a c t e r i s t i c O d o r s a n d F l a v o r s o f H e a t e d F a t s / O i l s aOil Heate d oil odors Fried-food flavorsSoybeanSBOLo LnLo Ln-HydCanolaCAOLo LnLo Ln-Br HydLo I~n-Hyd

Acrid, fried food, fishy, burnt, rubberyFried food, acridHydrogenated, fried food, fruityAcrid, burnt, fried food, fishy, rubberyFried food, acrid, burnt, woodyFried food, fruity, hydrogen atedHydrogenated, fried food, fruity

Fried food, fishyFried foodFried food, hydroge natedFried food, fishyFried foodFried food, hydroge natedFried food, hydroge nated

aSee Table 2 for abbreviations.

TABLE 6F r y i n g S t a b i l i t y o f S o y b e a n O i l s an d C a n o l a O i ls w i t h M o d i f ie d F a t t y A c i d C o m p o s i t i o n s

Soybean oils Canola oilsSensory analyses

Room odor intensi tyFrench-fry quality

Physical/chemical analyses (oils)Foam heightPolar compoundsFree fatty acids

Lo Ln = Lo Ln-Hyd < SBOSBO < Lo Ln --- Lo Ln-Hyd

Lo Ln = Lo Ln-Hyd < SBOLo Ln = Lo Ln-Hyd < SBOLo Ln < Lo Ln-Hyd < SBO

Lo Ln = Lo Ln-Br Hyd = Lo Ln-Hy d < CAOCAO < Lo Ln = Lo Ln-Br Hyd = Lo Ln-Hy d

Lo Ln = Lo Ln-Br Hyd = Lo Ln-Hyd < CAOLo Ln < Lo Ln-Br Hyd = Lo Ln-Hy d = CAOLo Ln - Lo Ln-Br Hyd < Lo Ln-Hy d < CAO

JAOCS, VoL 70, no. 10 (October 1993)


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98 8K. WARNER AND T.L. MOUNTS

signif icant ly improved qual i ty an d stabi l i ty compared tounmo difi ed oils. Hydro gen ati on of low-Ln oils did not im-prove the oi l qual i t y fur ther, and wi th the CAOs i t evend e c r e a s e d q u a l i t y b e c a u s e o f t h e h y d r o g e n a t i o noff-odors/flavors.ACKNOWLEDGEMENTSAll modified oils were obtained from I nte rMountai n Canola, Cin-naminson, NJ. The authors thank L. Parro tt for oil measurements;R. Holloway for fat ty acid composition dete rmination ; D. York forconducting frying and sensory evaluation studies; and the NCAURsensory panels.REFERENCES1. Evans , C.D., K. Warner, G.R. List and J.C. Cowan, J . A m . O i lC h e m . S o c . 49:578 (1972).2. Dobbs, J.E., M. Vaisey-Genser and R. Diamant, J. Ins t . Can . Sc i .Techno l . A i lmen t . 11:66 (1978}.3. Stevenson, S.G., M. Vaisey-Genser and N.A.M. Eskin, J . A m . O i lC h e m . S o c . 61:1102 (1984}.4. Frankel, E.N., K. Warner and T.L. Mounts , Ib id . 62:1354 (1985).5. Warner, K., T.L. Mounts and WF. Kwolek, I b i d 62.'1483 (1985).6. Cowan, J.C., C.D. Evans, H. Moser, G.R. List, S. Koritala, K.J.Moulton and H.J. Dutton, Ib id . 47:470 (1970).7. Cowan, J.C., H. Moser, G.R. List and C.D. Evans , Ib id . 48:835(1971}.

8. Cowan, J.C., S. Koritala, K. Warner, G.R. List, K.J. Moulton andC.D. Evans, Ib id . 50:132 (1973).9. Wilson, R.F., J.W. Burton and P. Kwanyuen, in E d i b l e F a t s a n dO i ls P r o c e ss i n g : B a s i c P r i n c i p le s a n d M o d e r n P r a c t i c e s, editedby D. Erickson, American Oil Chemist s' Society, Champaign,1989, pp. 355-359.10. Mounts, T.L., K. Warner, G.R. List, R. Kleiman, E.G. Hammondand J.R. Wilcox, I b i d . 65.'624 (1988}.11. Miller, L.A., and P.J. White, Ib id . 65.'1324 (1988).12. Liu, H., and P.J. White, Ib id . 69:533 (1992).13. Smouse, T., in F l a v o r C h e m i s t r y o f F a t s a n d O i l s , edited by T.Smouse, and D. Min, American Oil Chemists' Society, Cham-paign, 1985, pp. 85-116.14. Warner, K., in A n a l y s e s o f F a t s , O il s, a n d L i p o p r o t e i n s , editedby E. Perkins, American Oil Chemists' Society, Champaign, 1991,pp. 344-386.15. T h e O f f ic i a l M e t h o d s a n d R e c o m m e n d e d P r a c t i c e s o f t h eA m e r i c a n O i l C h e m i s t s ' S o c i e ty , 4th edn., Champaign, 1989.16. Waltking, A.E., and H. Wessels, J. A s s o c . O f f A n a l . C h e m .64:1329 {1981).17. Snedecor, G.W., S t a t i s t i c a l M e t h o d s , 5th edn., Ames, 1956.18. Dobarganes, M.C., and M.C. Perez-Camin(~ . A m . O i l C h e m . S o a65".101 (1988).19. Sebedio, J., A. Bonpunt, A. Grandgirard and J. Prevost, J. A g r i c .F o o d C h e m . 38:1862 {1990).20. Chu, Y., J . A m . O i l C h e m . S o c . 68:379 (1991}.

[Received December 21, 1992; accepted Ju ly 28, 1993]

JAOCS, Vol. 70, no. 10 (October 1993)

estabilidade oleo soja e canola na composição de ácidos graxos

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