DSpace at VNU: Research on identifying pahs in vegetable oil produced from some plants in open environment.

Some of vegetable oils were used to identify the Polycyclic Aromatic Hydrocarbons PAHs.. Contamination of PAHs in vegetable oils was due to technological processes or environmental sour

VNU JO U R N A L OF SCIEN C E Nat., Sci & Tech., T XX N01, 2004

RESEARCH ON IDENTIFYING PAHS IN VEGETABLE OIL

PRODUCED FROM SOME PLANTS IN OPEN ENVIRONMENT

Do Q u a n g H u y , Le N h u T h a n h

H anoi U niversity o f Science, V ietnam N a tio n a l U niversity

S u m m a r y Some of vegetable oils were used to identify the Polycyclic Aromatic

Hydrocarbons (PAHs) Contamination of PAHs in vegetable oils was due to

technological processes or environmental sources PAHs were detected in 3

vegetable oils, including raw coconut oil from Philippine, soya bean and olive- rapeseed oil from Vietnam Concentration of PAHs was found in coconut oil,

the maximum concentration was 22.048 |ig/kg PAHs’ concentration in soya

bean, olive-raspeseed oils was low, it was reduced during refining

Benzo(a)pyrene w asn’t detected in all samples, the maximum concentration of other PAHs was 10.640 ng/kg PAHs concentration in raw vegetable oils were

higher than refined oils.

1 I n t r o d u c t i o n

The p o l lu t a n ts were t r a n s p o r t e d into l a n d an d w a t e r t h r o u g h t h e air, and

a c c u m u l a t e d in p l a n t s This was one of the re a so n t h a t c a u se s PA Hs in some seeds

and fru its - m ateria l for oil production With the target of controlling food quality

a n d e x p la in i ng the a p p e a r a n c e of PAHs in cooking oil, we h av e c a r r i e d out a

r e s e a r c h to set up a met ho d to identify PAHs q u a n t i t y in some k i n d s of cooking oil, olive oil, soybean oil a n d coconut oil The r e s u l t shows t h a t t h e r e were PAHs in some of them

The r e l a ti o n s h i p b etw een p l a n t i n g e n v i r o n m e n t an.d pr o du ci ng process with the a p p e a r a n c e of P A Hs in vegetable oil h as been being explained

2 E x p e r i m e n t a l

2.1 M a t e r i a l s , c h e m i c a ls a n d i n s t r u m e n t s

The ra w coconut oil, soya b ean a nd o l iv e- rap ese ed oil was investigated

S t a n d a r d solution of PAHs in cyclohexane was used Solution s t a n d a r d of

n a p h t h a l e n e , a c e n a p h t h y l e n e , a c e n a p h t h e n e , p h e n a n t h r e n e , a n th r a c e n e ,

f l u o r a n t h e n e , fluorene, pyrene, b e nz o ( a ) a n t h r a c e n e , chrysene,

be n zo (b jk a)f lu or an th en es, benzo(e)pyrene, benzo(a)pyrene, perylene, indeno(123- cd)pyrene, d ib e n z ( a h ) a n th r a c e n e , benzo(ghi)perylene c o n ta in i n g 500 pg/àl

P h e n a n t h r e n e - d l O , p e r y l e n e - d l 2 a n d be n z o ( e ) p y r e n e - d l 2 wa s sup pl ied by Supelco,

c o n t a i n i n g 1 ng/àl each was p r e p a r e d in cyclohexane I n t e r n a l s t a n d a r d solution of

n a p h t h a l e n e - d 8, a c e n a p h t h y l e n e - d i o , p h e n a n t h r e n e - d i o , p e r y l e n e - d l 2 and

b e n z o (e ) p y r e n e - d l 2 , 0,1 àg/ml each was p r e p a r e d in cyclohexane All these

63

64 Do Q u a n g H uy, Le N h u T h a n h

solutoins were stored a t 5°c The solvents for e x t r a c t a n d clean up were cyclohexane, d i m e t h y lf o rm a m i d e , e th y l ac et a te , n - h e x a n e

Silica gel, 70-230 m es h for column c h ro m a t o g r a p h y w a s removed i m p u r i t i e s

possibly p resen t by h e a t in g overn igh t at 5 5 0 °c Before use, sta n d a rd ize by adding

10 % (v/v) of distilled w a te r, a ft e r ag it at i o n allow to s t a n d for 2 h

Bio-Bead S-X3, 200-400 m es h was also u s e d in c le an i n g proceduce

The H e w l l e t - P a r k a r d 5973 m a s s sp e c t r o m e t e r i n te r fa c ed wi th Agilent 6890

GC was used H P - 5 , 30 m X 0,25m m fused silica column wa s u se d wi th h e l i u m as the c a r r i e r gas a t 1.2ml/min, p r e s s u r e 6.31psi Spli tless injection 2 50 ° c was employed The oven t e m p e r a t u r e was p r o g r a m m e d 70°c, 1 min, 5°c/min, 280°c , a nd keeping a t 280°c u nt il all c om p on e nt s were eluted

The m a s s sp e c t r o m e t e r p a r a m e t e r s u s e d were as follows: elect ron im pa ct energy 70 eV, source t e m p e r a t u r e 250°c, t r a n s f e r line 280°c

In the SIM mode, th e ions monit or ed were m/e 136, 68 ( n a p h t h a l e n e - d 8), m/e

128, 129 ( n a p h t h a l e n e ) , m/e 162, 164 (a c en a p h t h y le n e - d l O ), m/e 151, 152 (ace na ph th yle ne) , m/e 153, 154 (ac en a p ht h en e ), m/e 164, 166 (fluorene), m/e 186,188 ( p h e n a n t h r e n e - d l O ) , m/e 176,178 ( p h e n a n t h r e n e , a n t h r a c e n e ) , m/e 200, 202 (fluoran then e, pyrene), m/e 226,228 ( be nz o( a)a nt hra cen e, chrysene), m/e 250, 252 (benzo( bjk a)fluo ranth ene s, benzo(e)pyrene, benzo(a)pyrene, perylene), m/e 260, 264 ( p er yl e ne - dl 2, b e nz o (e ) py re n e- d l2 ) , m/e 276, 277 (indeno(123-cd)pyrene, benzo(ghi)perylene), m/e 278, 279 ( d ib en z (a h )a n th ra ce ne ), Fig u re 1

2.2 C le a n u p p r o c e d u r e

25 g ra m of veg etab le oil in 250 ml s e p a r a t i n g funnel, ad d 2 ml i n t e r n a l

s t a n d a r d solution was solved in 100ml cyclohaxane T h e m ix t u r e was e x tr a c t e d by

di m e t h y lf o r m am i d e : H 20 (9:2, v/v) t h r e e ti m e s wit h p o rt ion s of 50 ml, 25 ml, 25 ml The e x tr a ct of sa m p le was di lu te d wi th 100 ml of 1 % N a 2S 0 4 solution After a dd in g

50 ml cyclohexane, t h e m it u r e was e x tr a c t e d a g a i n wi th 25 ml of

d i m e th v lf or m am id e : w a t e r (9:2; v/v) The e x t r a c t was w a s h e d wi th di sti ll ed w a t e r

an d t h e n dried wit h a n h y d r o u s sod iu m sulfate T h e e x t r a c t w a s c o n c e n t r a t e d on a

ro t ar y e v a p o r a t o r to 1 ml a t 40°c

C h r o m a t o g r a p h y colu mn (500 m m X 0.6 m m i.d.) was pa cke d a 5 g r a m of:

silica gel (content 10 % of water) Load p r e p a r e d e x t r a c t on th e column 90 ml of

cyclohexane wa s us e d a s a solvent to clean up a n d e lut e PAHs from column Discard

10 ml of first frac tio n (FI), a n d c o n ce n tr a te 80 ml of secơnd fr at io n to 2 ml (F2) Bio-Bead S-X3 colu mn ( 300 m m X 20 mm) was us e d to cle an up a g a i n th e F2 solution The m i x t u r e of cyclohexane : e t h y l a c e t a t e (1:2, v/v) w a s u s e d as a solvent

to clean up a nd e lut e P A Hs from column Flow r a t e of th e m ix t u r e of cyclohexane :

e th y l ac et a te (1:2, v/v) wa s 5 ml/min Adding 3 ml of e t h y l a c e t a t e to F2 solution, load

th is solution on the column Collect th e 50 - 120ml fractiort a n d c o n c e n tr a te on a

R esea rch on id e n tify in g p a h s in vegetable oil fr o d u c e d f r o m 65

r ot ary e v a p o r a t o r to 5 ml T r a n f e r a re s i d u e into a sa m p le vial, dr y n es s u n d e r nitrogen s t r e a m , a n d dissolve in 100 àl toluene T his solution was us e d to identify PAHs on GC-MS

3 R e s u l t s a n d d i s c u s s i o n

A s a m p l e of r a w coconut oil wa s produced in P h i li pp in e was analy zed to identify PAHs The sa m p le h a s not b e e n refined, still h a s distinctive smell and colour of th e i n p u t m a t e r i a l

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Fi gure 1 Mass chromatograms by SIM mode of PAHs.

According to th e table 1, the P A Hs c o n c e n tr a ti o n in t h e sa m p le was r a t h e r high, the c o n c e n t r a t i o n r an g e was from not found to 22.048 ng/kg Among group of PAHs, g r e a t a t t e n t i o n h a s been paid to group of s u b s t a n c e s wi th hi gh cancer

p o t e n t i a l it y a s benzo(a)pyrene, b e n z o (a ) a n t h r a c e n e , d i b e n z ( a ) a n th ra c e n e The

co n ce n tr a ti o n r a n g e was from not found to 9.478 |ig/kg C o m p a r e d to the benzo(a)pyrene - p e r m i t t e d s t a n d a r d in I t a l i a n food, be n zo( a)p yr en e in r a w coconut oil was 3 t i m e s hig her Moreover, th e a p p e a r a n c e of hi gh PA H s co nc e n tra tio n

m e a n s t h e hi gh r i s k of be ing cancer

T a b l e 1 Concentration of PAHs in vegetable oils (ụg/kg)

coconut oil

Soya be an oil 1

Soya bean oil 2

Olive- rapeseed oil 1

Olive- rapeseed oil 2

Note : (-) n o t de tected

The PAH s c o n t e n t in P h i li p pi n e r a w coconut oil was co mp ar ed h i g h e r t h a n

t h a t of G e r m a n However, benzo(a)p yre ne in G e r m a n y r a w coconut oil wa s very high, from 0.5 to 2.3 |!g/kg The an al y zi n g r e s u l t was completely r e l e v a n t to the conclusion t h a t r a w coconut oil c o n ta in s h i g h e s t PAHs content

Two s a m p l e s of refine d soy bean oil ha ve be en a na ly ze d to find o u t PAHs The PAHs c o n c e n tr a ti o n r a n g e was from not found to 7.68 |!g/kg for each N a p h t h a l e n e was identified hi g h es t Among 15 PAH s u b s t a n c e s we analy zed

b e n zo (a ) a n th r ac en e , benzo(a)pyrene, d i b e n z ( a ) a n th r a c e n e , which we re most poisonous, were not found

Co m pa re d to th e benzo (a) pyr en e - p e r m i t t e d s t a n d a r d in I t a l i a n food, the benzo(a)pyrene c o n c e n tr a ti o n in t h e s a m p l e s was u n d e r th e s t a n d a r d However,

t h r o u g h first e x p e r i m e n t s , t h e s e two soybean oil s a m p le s co n ta in some PAHs

ca us in g cancer as in de n o (123-cd)pyrene wit h th e c o n c e n tr a ti o n of 1.11 jag/kg in

sa mple 1, a n d 5.57 |ig/kg in sa m p le 2

The existence of P A H s in soybe an oil s a m p l e s was due to th e a c c u m u l a t i o n in

gr ain s an d the f o rm at io n in t h e processing Soybean p l a n t w a s a h e r b a c e o u s p l a n t with sh or t height, larg e a n d ro ugh leaves easily a b so rb in g PAH s d e p o s i t e d by polluted air Besides, in processing, soybean with high p r o t e i n is possibly con ver ted

R esea rc h on id e n tify in g p a h s in vegetable o il fr o d u c e d from 67

into PAHs However, most PAHs were e li m in a te d d u r i n g the r a w oil refining process

We also c arr y out an al y zi n g PAHs in two s a m pl e s of olive oil This was the

m a t e r i a l with high oil a n d low pr ot ein content Th oug h m a t e r i a l was imp or ted from

t e m p e r a t e climate cou ntries , the producing process was hi gh ly economically effective The PAHs c o n te n t in the sa m p les was low, r a n g i n g from not found to 10.61 ng/kg The s a m p l e s con tain some c a n c e r - p o t e n t i a l sub s ta nc es , as

b e nz o( b) flu or an th ene 0.123 ng/kg in sample 2 a n d indeno(12 3- cd )py re ne 0.058

|ig/kg in sa m pl e 1 Benzo(a)pyrene was not found in both sa mples

O u r s a m p l e - a n a l y z i n g r e s u l t s were showed t h a t th e PA H s c o nc e n tr a tio n in olive oil were lowest The re a so n can be t h a t colza a nd olive - th e m a t e r i a l supply - grow a n d develop in a n open e n v i r o n m e n t with low PAHs c o n c e n tr a ti o n a n d t h a t the c om po n e nt s in th e s e g r a i n s were less likely to be co nverted into PAHs

4 C o n c l u s i o n

T h r o u g h r e s e a r c h on identifying PAHs in vegetable oil, we h av e d r a w n out the following conclusions: PAHs c o nt e n t in Phil ip pin e r a w coconut oil was high, from not found to 22.048 jig/kg Benzo(a)pyrene co n ce n tr a ti o n in th e sa m pl e is 0.088 fig/kg, t h e total PA H s up to 45.415 |ig/kg PAHs c o n te n t in t h e refined soybean sam ple w a s low, from not found to 7.68 |ig/kg Benzo(a)pyrene wa s not found in the two sam ple s Soybean oil does not conta in PAHs as t h e y a r e e l i m i n a t e d du ri ng ref ining process PAH s c o n te n t in olive a nd colza oil s a m p le s were quite low, the

co n ce n tr a ti o n r an g e from not found to 10.61 |ig/kg C om pa r e d to th e s t a n d a r d , the

benzo(a)pyrene co n ten t in olive and cozal oil w as perm itted PA H s co n ten t in raw

oil was m uch more h i g h e r t h a n in refined oil C o l o u r - w as h i n g m et h o d el i m in a te s most poisonous s u b s t a n c e s t h a t cause cancers However, PA H s have be en found

t h r o u g h four refined oil sam ple s Pr o d uc er s should ha ve m e t h o d s to reject th em completely from processed oil

R e f e r e n c e

1 Hopia A., Pyysalo H & Wichstromk, Margarines, b u t te r and vegetable oils as

sources of PAHs, I.Am oil chem.soc., 63, 1996, pp 889-893.

2 Menichini E., Bocca A., Merli F & Monfedni F., PAHS in olive oils on the Italian

market, Food A ddit Contam., 8 , 1991, pp 363-369.

3 Sagredos AN., Sinha - Roy D & Thomas A., Determination, sources & composition

of PAHs in oils and fats, Fat Sci T e c h n o 90, 1998, pp 76-81 (in German).

68 Do Q u a n g H uy9 Le N h u T h a n h

TAP CHỈ KHOA HOC DHQGHN, KHTN & CN T XX, sỏ' 1, 2004

N G H I Ê N CỨU XÁC Đ Ị N H CÁC HI D R O C A C B O N T H Ơ M ĐA VÒNG

TR ONG DẦU ẢN SẢN XUẤT t ừ q u ả, h ạ t c ủ a m ộ t s ố LOÀI T H ự C VẬT

GI E O T R Ổ N G T RO NG MÔI T RƯ ỜN G MỞ

Đỗ Quang Huy, Lê Như Thanh

Trường Đ ại học Khoa học T ự nhiên, Đ ại học Quốc gia H à nội

Về b ả n c h ấ t tự nhi ên, các loại d ầ u thực v ậ t đều k h ô n g ch ứa các hidrocacbon thơm đa vòng (PAHs), c h ú n g bị n h i ễ m b ẩ n các c h ấ t nà y t r o n g các q u á t r ì n h xử lý kỹ

t h u ậ t ha y t ừ môi trường C h ú n g tôi đ ã tiến h à n h xác đ ịn h PA Hs tr on g b a loại dầ u thực v ậ t : d ầ u dừa của P h i l i p p in (thô), d ầ u n à n h và d ầ u o l i u - h ạ t cải (đã q u a t in h luyện) của Việt nam Đã p h á t h i ệ n r a h à m lượng cao củ a PA Hs t r o n g d ầ u dừa với giá trị cực đại là 22,048 ụg/kg Trong khi đó, h à m lượng của PA Hs t r o n g d ầ u n à n h

và d ầ u oliu- h ạ t cải là t h ấ p và h à m lượng nà y giảm kh i được t i n h chế Be nzo(a)- pyrene kh ôn g tìm t h ấ y tr o n g cả ba loại dầu Tóm lại, PAHs đượ c tìm t h ấ y tr ong cả

ba loại d ầ u thực v ậ t và h à m lượng của nó tr ong d ầ u thô cao hơn t r o n g d â ù đã được tin h chế