T¹p chÝ Hãa häc, T. 43 (4), Tr. 411 - 415, 2005<br />
<br />
<br />
<br />
Nghiªn cøu chuyÓn hãa -Carrageenan thµnh<br />
-Carrageenan<br />
PhÇn I - Tèi u hãa cÊu tróc cña Carrageenan b»ng phÇn mÒm<br />
tÝnh to¸n hãa häc Hyper Chem 7.02<br />
<br />
§Õn Tßa so¹n 23-6-2004<br />
ph¹m hång h¶i, nguyÔn xu©n nguyªn, trÇn §×nh To¹i<br />
ViÖn Khoa häc v$ C«ng nghÖ ViÖt Nam<br />
<br />
<br />
Summary<br />
Carrageenan is used widly in the food industry. The use depents on their character. That is<br />
very important to determine their composition - structure. We have extracted the carrageenan<br />
from Red seaweed. In order to investigate its transformation (translatable properties), we<br />
summary a optimum structure of this carrageenan by standard calculation program Hyper Chem<br />
7.20. About the optimum structure where is a information of some properties of this carrageenan<br />
as folowing: linked length, linked corners, and formula of carragenan.<br />
<br />
<br />
I - Më ®Çu biÕt thªm vÒ c¬ chÕ, ®éng häc cña cña ph¶n øng<br />
chuyÓn hãa carrageenan.<br />
Carrageenan l polysaccarit tù nhiªn ® îc Chóng t«i xin giíi thiÖu mét phÇn trong<br />
t¸ch ra tõ rong biÓn (ng nh rong §á ch ¬ng tr×nh nghiªn cøu cña chóng t«i b i ë b¸o<br />
Rhodophyta) [1]. Ngo i chøc n¨ng l m vËt liÖu n y.<br />
t¹o nªn th nh tÕ b o v l nguån ® êng dù tr÷,<br />
polysaccarit gi÷ nhiÒu chøc n¨ng kh¸c quan II - CÊu tróc v% tÝnh chÊt cña<br />
träng ®èi víi tÕ b o nh trao ®æi chÊt v b¶o vÖ<br />
Carrageenan<br />
tÕ b o nªn chóng cã ®é bÒn c¬ häc cao. V× b¶n<br />
chÊt nªu trªn, kÕt hîp víi mét sè tÝnh chÊt ®Æc<br />
Carrageenan l hçn hîp c¸c galactan sulfat.<br />
biÖt cña chóng nh t¹o gel ë nång ®é rÊt thÊp<br />
§¬n vÞ cÊu tróc cña carrageenan gåm 2 ® êng<br />
( 1%), ®é nhít cao rÊt dÔ t¹o m ng, m c¸c<br />
®¬n - -D-galactose (®¬n vÞ cÊu tróc G,D) hoÆc<br />
polysaccarit n y ®I ® îc sö dông réng rIi trong<br />
nhiÒu ng nh cña kinh tÕ quèc d©n, ®Æc biÖt l gåm ® êng ®¬n - -D-galactose v 3,6-anhi®ro-<br />
trong chÕ biÕn s÷a, thÞt. Ngo i ra, chóng cßn l D-galactose (®¬n vÞ cÊu tróc G,DA) g¾n víi<br />
nguån nguyªn liÖu quý ®Ó l m d îc phÈm, chÕ nhau bëi liªn kÕt (1-4) [1, 3]. C¸c ®¬n vÞ cÊu<br />
thuèc [2]. tróc n y liªn kÕt víi nhau qua mèi liªn kÕt (1-<br />
3) t¹o th nh carrageenan.<br />
V× nh÷ng lý do trªn, viÖc nghiªn cøu<br />
carrageenan kh«ng chØ cã ý nghÜa vÒ mÆt khoa Theo ®¬n vÞ cÊu tróc, cã thÓ chia<br />
häc m cßn cã ý nghÜa lín vÒ mÆt thùc tÕ. V× carrageenan th nh 2 nhãm:<br />
vËy, ®Ó ®¹t môc ®Ých nghiªn cøu chóng t«i sö - Nhãm kh«ng cã 3,6-anhi®ro-D-galactose,<br />
dông phÇn mÒm hãa l îng tö Hyper Chem ®Ó cã ®¬n vÞ cÊu tróc (G,D) nh : c¸c d¹ng µ-; -,<br />
tÝnh to¸n nh÷ng th«ng sè cÇn thiÕt cho viÖc hiÓu -carrageenan.<br />
<br />
411<br />
- Nhãm cã 3,6-anhi®ro-D-galactose, cã ®¬n ý l chuyÓn carrageenan tõ nhãm cÊu tróc<br />
vÞ cÊu tróc (G,DA) nh : c¸c d¹ng -; -, -; - kh«ng cã liªn kÕt 3,6-anhi®ro-D-galactose<br />
carrageenan. (G,D) th nh carrageenan thuéc nhãm cã liªn kÕt<br />
§I cã mét sè c«ng bè vÒ nghiªn cøu m« 3,6-anhi®ro-D-galactose (G,DA) [5]. Qu¸ tr×nh<br />
h×nh hãa cÊu tróc cña carrageenan [4]. chuyÓn hãa n y ® îc thùc hiÖn trong m«i<br />
tr êng kiÒm m¹nh hoÆc cã thÓ do c¸c t¸c nh©n<br />
§èi víi carrageenan, mét qu¸ tr×nh ®¸ng l u oxi hãa khö kh¸c [6] (h×nh 1).<br />
<br />
CH2OH CH2OSO3- CH2OH CH2OSO3-<br />
OH O O O O<br />
O OH<br />
OH OH O O<br />
O O<br />
O H (30%) OSO3 -<br />
O H (30%) OSO3-<br />
SO3- (70%) SO3- (70%)<br />
-carrageenan -carrageenan<br />
H×nh 1: Qu¸ tr×nh chuyÓn hãa carrageenan trong m«i tr êng kiÒm m¹nh<br />
<br />
Ngo i qu¸ tr×nh biÕn ®æi cÊu tróc, ®èi víi 2. Ph ¬ng ph¸p nghiªn cøu th nh phÇn, cÊu<br />
carrageenan cßn cã thÓ cã qu¸ tr×nh chuyÓn hãa tõ tróc cña carrageenan b»ng phæ Céng<br />
d¹ng n y sang d¹ng kh¸c do t¹o thªm hoÆc mÊt h ëng tõ h¹t nh©n (NMR)<br />
nhãm sulfat. Ng y nay phæ céng h ëng tõ h¹t nh©n<br />
Tïy h m l îng v vÞ trÝ cña nhãm sulfat (NMR) l mét trong c¸c c«ng cô chuÈn ®Ó x¸c<br />
trong cÊu tróc, m carrageenan cã d¹ng kh¸c ®Þnh cÊu tróc ph©n tö. Chóng t«i sö dông<br />
nhau, thÝ dô nh : -carrageenan (25% sulfat); - ph ¬ng ph¸p n y ®Ó nghiªn cøu carrageenan.<br />
carrageenan (32% sulfat); -carrageenan (35% ChuÈn bÞ mÉu v ghi phæ: Hßa tan 20 - 30<br />
sulfat). mg mÉu trong D2O v 1-5% DMSO ®Õn nång<br />
Nghiªn cøu cÊu tróc cña carrageenan b»ng ®é 2-3 %, ë 80oC. ViÖc ghi phæ ® îc thùc hiÖn<br />
trªn m¸y phæ NMR ®é ph©n gi¶i cao Bruker<br />
ph ¬ng ph¸p céng h ëng tõ h¹t nh©n cho thÊy<br />
Avent 500 MG t¹i ViÖn Hãa häc, ViÖn Khoa<br />
r»ng nhãm sulfat ¶nh h ëng rÊt lín tíi c¸c gi¸ häc v C«ng nghÖ ViÖt Nam.<br />
trÞ dÞch chuyÓn hãa häc cña c¸c vÞ trÝ cacbon<br />
trong cÊu tróc cña polysaccarit n y. 3. Ph ¬ng ph¸p tÝnh to¸n b»ng phÇn mÒm<br />
tÝnh to¸n hãa häc Hyper Chem 7.02<br />
§iÒu n y cã thÓ thÊy ® îc khi so s¸nh ®é<br />
chuyÓn dÞch hãa häc cña c¸c lo¹i carrageenan Hyper Chem l phÇn mÒm hãa l îng tö<br />
th êng gÆp trong tù nhiªn [7, 8]. ® îc sö dông réng rIi ®Ó m« h×nh hãa v thiÕt<br />
kÕ ph©n tö. Hyper Chem cho phÐp x©y dùng c¸c<br />
Iii - Nguyªn liÖu v% ph,¬ng ph¸p cÊu tróc hai chiÒu v ba chiÒu cña nhiÒu lo¹i<br />
nghiªn cøu ph©n tö ®Æc biÖt l c¸c ®¹i ph©n tö nh protein,<br />
polyme... Nh÷ng tÝnh to¸n trong Hyper Chem<br />
®Òu tËp trung gi¶i quyÕt vÊn ®Ò thÕ n¨ng t ¬ng<br />
1. Nguyªn liÖu cho nghiªn cøu<br />
t¸c gi÷a c¸c electron dùa v o viÖc gi¶i gÇn ®óng<br />
Carrageenan-s¶n phÈm hîp t¸c cña phßng c¸c ph ¬ng tr×nh chøa tÝch ph©n Coulomb v<br />
thÝ nghiÖm enzym ViÖn Hãa häc víi Liªn hiÖp tÝch ph©n xen phñ gi÷a c¸c electron. Hyper<br />
KHSX C«ng nghÖ hãa häc, ViÖn Hãa häc c¸c Chem sö dông c¸c ph ¬ng ph¸p tÝnh gÇn ®óng<br />
hîp chÊt thiªn nhiªn t¸ch chiÕt tõ rong Hång b¸n kinh nghiÖm nh AM1, PM3 v ZINDO.<br />
v©n Eucheuma gelatinae (ng nh rong §á C¸c ph ¬ng ph¸p tÝnh gÇn ®óng n y cho<br />
Rhodophyta). nh÷ng kÕt qu¶ phï hîp víi thùc nghiÖm. Trong<br />
<br />
412<br />
®ã, ph ¬ng ph¸p PM3 c¬ b¶n dùa trªn viÖc bá mÆt cña ph©n tö; thÓ tÝch ph©n tö.<br />
qua sù xen phñ vi ph©n gi÷a hai nguyªn tö. Do §iÖn tÝch nguyªn tö (QA): QA = ZA - PA,<br />
®ã ph ¬ng ph¸p n y ®I ® îc sö dông ®Ó tÝnh trong ®ã: ZA l ®iÖn tÝch h¹t nh©n nguyªn tö A<br />
to¸n theo c¸c b íc nh sau: (sè electron hãa trÞ), PA l mËt ®é electron.<br />
- X©y dùng cÊu tróc hai chiÒu v ba chiÒu<br />
cña ®¬n vÞ cÊu tróc carrageenan. IV - KÕt qu¶ nghiªn cøu<br />
- Tèi u hãa c¸c cÊu tróc n y b»ng ph ¬ng<br />
ph¸p PM3 víi ®é héi tô 0,001. 1. KÕt qu¶ tÝnh to¸n<br />
- TÝnh ®é dÞch chuyÓn hãa häc cña c¸c KÕt qu¶ tÝnh to¸n tèi u hãa ®é d i v gãc<br />
carrageenan trong phæ 13C-NMR liªn kÕt trong ®¬n vÞ cÊu tróc cña carrageenan<br />
- TÝnh to¸n c¸c tham sè nh : diÖn tÝch bÒ ® îc tr×nh b y trong c¸c b¶ng 1 v 2.<br />
<br />
B¶ng 1: ®é d i liªn kÕt gi÷a c¸c nguyªn tö trong ®¬n vÞ cÊu tróc cña carrageenan<br />
<br />
®é d i liªn kÕt ®é d i liªn kÕt<br />
Nguyªn tö Nguyªn tö<br />
Thùc Tèi u Thùc Tèi u<br />
O[14]-H[]30 0,952 0,942 C[1]-C[2] 1,562 1,505<br />
C[15]-O[16] 1,345 1,421 C[1]-C[6] 1,577 1,505<br />
C[15]-H[44] 1,133 1,111 C[1]-O[14] 1,358 1,421<br />
C[15]-H[45] 1,127 1,111 C[1]-H[49] 1,138 1,111<br />
O[16]-H[29] 0,955 0,942 C[2]-C[3] 1,544 1,514<br />
O[17]-C[25] 1,348 1,402 C[2]-O[17] 1,365 1,402<br />
C[18]-O[19] 1,219 1,402 C[2]-H[50] 1,136 1,111<br />
C[18]-H[42] 3,934 1,111 C[3]-C[4] 1,521 1,505<br />
C[18]-H[43] 1,134 1,111 C[3]-H[45] 1,121 1,113<br />
O[19]-S[20] 1,751 - C[3]-H[55] 1,119 1,113<br />
S[20]-O[26] 1,487 1,450 C[4]-O[5] 1,499 1,402<br />
S[20]-O[27] 1,495 1,450 C[4]-O[13] 1,301 1,402<br />
S[20]-O[28] 1,490 1,450 C[4]-H[56] 1,144 1,109<br />
O[21]-C[22] 1,345 1,402 O[5]-C[6] 1,450 1,402<br />
C[22]-H[39] 1,119 1,111 C[6]-C[15] 1,508 1,505<br />
C[22]-H[40] 1,121 1,111 C[6]-H[48] 1,111 1,111<br />
C[22]-H[41] 1,124 1,111 C[7]-C[8] 1,558 1,505<br />
O[23]-H[31] 0,953 0,942 C[7]-O[12] 1,359 1,402<br />
O[24]-S[32] 1,655 - C[7]-C[18] 1,503 1,505<br />
C[25]-H[36] 1,118 1,111 C[7]-H[52] 1,145 1,111<br />
C[25]-H[37] 1,121 1,111 C[8]-C[9] 1,571 1,505<br />
C[25]-H[38] 1,122 1,111 C[8]-O[13] 1,381 1,402<br />
S[32]-O[33] 1,503 1,450 C[8]-H[53] 1,142 1,111<br />
S[32]-O[34] 1,498 1,450 C[9]-C[10] 1,568 1,505<br />
S[32]-O[35] 1,499 1,450 C[9]-O[23] 1,364 1,421<br />
C[2]-C[1]-C[6] 118,727 109,510 C[9]-H[51] 1,138 1,111<br />
C[2]-C[1]-O[14] 106,519 107,700 C[10]-C[11] 1,560 1,496<br />
C[2]-C[1]-H[49] 109,391 109,390 C[10]-O[24] 1,315 1,402<br />
C[6]-C[1]-O[14] 110,133 107,700 C[10]-H[47] 1,161 1,111<br />
C[6]-C[1]-H[49] 109,391 109,390 C[11]-O[12] 1,415 1,402<br />
O[14]-C[1]-H[49] 101,236 106,700 C[11]-O[21] 1,346 1,402<br />
C[1]-C[2]-C[3] 115,823 109,510 C[11]-H[46] 1,148 1,109<br />
413<br />
B¶ng 2: Gãc liªn kÕt gi÷a c¸c nguyªn tö trong ®¬n vÞ cÊu tróc cña carrageenan<br />
<br />
Gãc liªn kÕt gi÷a Gãc liªn kÕt Gãc liªn kÕt gi÷a Gãc liªn kÕt<br />
nguyªn tö Thùc Tèi u nguyªn tö Thùc Tèi u<br />
C[7]-C[8]-H[53] 104,282 109,390 C[1]-C[2]-O[17] 108,519 107,700<br />
C[9]-C[8]-O[13] 107,293 107,700 C[1]-C[2]-H[50] 109,045 109,390<br />
C[9]-C[8]-H[53] 112,273 109,390 C[3]-C[2]-O[17] 107,611 107,700<br />
O[13]-C[8]-H[53] 99,423 106,700 C[3]-C[2]-H[50] 103,632 109,390<br />
C[8]-C[9]-C[10] 113,565 109,510 O[17]-C[2]-H[50] 112,236 106,700<br />
C[8]-C[9]-O[23] 101,102 107,700 C[2]-C[3]-C[4] 119,297 109,500<br />
C[8]-C[9]-H[51] 107,400 109,390 C[2]-C[3]-H[54] 110,790 109,410<br />
C[10]-C[9]-O[23] 117,389 107,700 C[2]-C[3]-H[55] 107,709 109,410<br />
C[10]-C[9]-H[51] 107,501 109,390 C[4]-C[3]-H[54] 104,726 109,410<br />
O[23]-C[9]-H[51] 109,425 106,700 C[4]-C[3]-H[55] 111,439 109,410<br />
C[9]-C[10]-C[11] 114,488 109,510 H[54]-C[3]-H[55] 101,422 109,400<br />
C[9]-C[10]-O[24] 114,761 107,700 C[3]-C[4]-O[5] 103,765 107,700<br />
C[9]-C[10]-H[47] 99,652 109,390 C[3]-C[4]-O[13] 111,675 107,700<br />
C[11]-C[10]-O[24] 116,637 107,700 C[3]-C[4]-H[56] 112,950 109,390<br />
C[11]-C[10]-H[47] 98,958 109,390 O[5]-C[4]-O[13] 116,492 97,000<br />
O[24]-C[10]-H[47] 109,342 106,700 O[5]-C[4]-H[56] 98,701 106,700<br />
C[10]-C[11]-O[12] 106,540 107,700 O[13]-C[4]-H[56] 112,434 106,700<br />
C[10]-C[11]-O[21] 111,275 107,700 C[4]-O[5]-C[6] 138,573 106,800<br />
C[10]-C[11]-H[46] 112,850 109,390 C[1]-C[6]-O[5] 103,716 107,700<br />
O[12]-C[11]-O[21] 117,849 97,000 C[1]-C[6]-C[15] 127,015 109,510<br />
O[12]-C[11]-H[46] 95,867 106,700 C[1]-C[6]-H[48] 109,393 109,390<br />
O[21]-C[11]-H[46] 111,619 106,700 O[5]-C[6]-C[15] 111,971 107,700<br />
C[7]-O[12]-C[11] 128,720 106,800 O[5]-C[6]-H[48] 106,702 106,700<br />
C[4]-O[13]-C[8] 153,886 106,800 C[15]-C[6]-H[48] 96,571 109,390<br />
C[1]-O[14]-H[30] 113,238 106,900 C[8]-C[7]-O[12] 111,595 107,700<br />
C[6]-C[15]-O[16] 112,829 107,400 C[8]-C[7]-C[18] 121,065 109,510<br />
C[6]-C[15]-H[44] 109,409 109,410 C[8]-C[7]-H[52] 102,432 109,390<br />
C[6]-C[15]-H[45] 109,409 109,410 O[12]-C[7]-C[18] 110,598 107,700<br />
O[16]-C[15]-H[44] 106,700 106,700 O[12]-C[7]-H[52] 112,273 106,700<br />
O[16]-C[15]-H[45] 106,700 106,700 C[18]-C[7]-H[52] 97,538 109,390<br />
H[44]-C[15]-H[45] 111,783 109,400 C[7]-C[8]-C[9] 113,053 109,510<br />
C[15]-O[16]-H[29] 110,881 106,900 C[7]-C[8]-O[13] 119,685 107,700<br />
<br />
2. KÕt qu¶ nghiªn cøu tèi u hãa ®¬n vÞ cÊu tö trong ®¬n vÞ cÊu tróc cña carrageenan ® îc<br />
tróc cña carrageenan tr×nh b y trªn h×nh 2 v x©y dùng m« h×nh ®¬n<br />
vÞ cÊu tróc tèi u hãa vÒ mÆt n¨ng l îng cña<br />
KÕt qu¶ tÝnh to¸n ®iÖn tÝch cña c¸c nguyªn carrageenan ® îc tr×nh b y trªn h×nh 3.<br />
<br />
414<br />
C«ng tr×nh n$y ®@îc ho$n th$nh víi sù hç trî<br />
kinh phÝ cña Héi ®ång Khoa häc tù nhiªn.<br />
<br />
T%i liÖu tham kh¶o<br />
<br />
1. W. Mackie and R. D. Preston. Chapter 2.<br />
Cell wall and intercellular region<br />
polysaccharides (7. Sulphated polysaccha-<br />
rides), Algal physiology and Biochemistry,<br />
P. 63 - 69 (1976).<br />
2. Gerhard A. De Ruiter and Brian Rudolph.<br />
Carragenan biotechnology. Trends in Food<br />
H×nh 2: §iÖn tÝch c¸c nguyªn tö trong ®¬n vÞ science & Technology, 8, P. 389 - 395<br />
cÊu tróc cña carrageenan (1997).<br />
3. Stepanenko B. N. Chemistry and<br />
Biochemistry of Carbohydrates (Polysac-<br />
charides), Moscow (tiÕng Nga) (1978).<br />
4. S. Janaswamy, R. Chandrasekaran. Carbo-<br />
hydrate Research, 335, P. 181 - 194 (2001).<br />
5. Christian W. Kasbauer, Dietrich H. Paper,<br />
Gerhard Franz. Carbohydrate Research,<br />
330, P. 427 - 430 (2001).<br />
6. Thanh Thi Thu Thuy. Structure of sulfated<br />
polysaccharides in aqueous solution.<br />
Doctoral thesis submitted to Kyoto Institute<br />
H×nh 3: CÊu tróc tèi u vÒ mÆt n¨ng l îng ®¬n of Technology (2002).<br />
vÞ cÊu tróc cña carrageenan 7. Ruth Falshaw and Richard H. Furneaux.<br />
Carrageenans from the tetrasporic stages of<br />
V - KÕt luËn Gigartina clavifera and Gigartina alveata<br />
(Gigartinaceae, Rhodophyta) Carbohydrate<br />
§I nghiªn cøu tèi u hãa ®é d i v gãc liªn Research, 276, P. 155 - 165 (1995).<br />
kÕt trong ®¬n vÞ cÊu tróc cña carrageenan ®Ó 8. Ruth Falshaw and Richard H. Furneaux.<br />
tÝnh to¸n tèi u vÒ mÆt n¨ng l îng v x©y dùng Carbohydrate Research, 252, P. 171 - 182<br />
m« h×nh ®¬n vÞ cÊu tróc cña polysaccarit n y. (1994).<br />
<br />
<br />
<br />
<br />
415<br />