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Sains Malaysiana 39(6)(2010):
969–973
Molecular
Characterisation of Sago Starch Using Gel Permeation Chromatography Multi-Angle
Laser Light Scattering
(Pencirian
Molekul Kanji Sago Menggunakan Kromatografi Penelapan Gel Serakan Cahaya Laser
Pelbagai Sudut)
Zainon
Othman*
Malaysian
Nuclear Agency, Bangi, 43000 Kajang, Selangor, D.E., Malaysia
Saphwan
Al-Assaf
Phillips
Hydrocolloids Research Centre
Glyndwr
University, Mold Road, Wrexham LL 2AW, United Kingdom
Osman
Hassan
Food
Science Programme, School of Chemical Sciences and Food Technology
Faculty
of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi,
Selangor D.E., Malaysia
Received:
8 April 2009 / Accepted: 1 June 2010
ABSTRACT
The
molecular characteristics of sago starch (native and debranched) were
determined using a gel permeation chromatograpy multi-angle laser light
scattering (GPC-MALLS)
method. The method involves the optimisation of sample solubilisation and GPC operating conditions. The weight-average
molecular weight Mw of
native and debranched sago starch determined was 29.1 ± 2.1 °— 106 and 1.87 ± 0.4 °— 105 gmol-1 respectively while radius of gyration Rg was 123.6 and 59.3 nm respectively. The
reduction in Mw and
Rg in
debranched sago was attributed to the hydrolysis of α-1,6 glycosidic
linkages by pullulanase to smaller oligosaccharides.
Keywords: GPC-MALLS;
radius of gyration; sago starch; weight-average molecular weight
ABSTRAK
Pencirian
molekul kanji sagu (asli dan dinyahcabang) telah dijalankan menggunakan kaedah
kromatografi penelapan gel serakan cahaya laser pelbagai sudut (GPC-MALLS).
Kaedah pencirian ini melibatkan pengoptimuman pelarutan sampel dan keadaan
operasi kromatografi. Berat purata berat molekul Mw kanji sago asli adalah 29.1 ± 2.1 °— 106 berbanding 1.87 ± 0.4 °— 105 gmol-1 untuk kanji sago dinyahcabang dan
legaran jejari Rg adalah
123.6 nm untuk kanji asli berbanding 59.3 nm untuk kanji dinyahcabang.
Penurunan nilai Mw dan
Rg dalam
kanji sago dinyahcabang adalah hasil hidrolisis ikatan glikosidik α-1,6
oleh enzim pullulanase ke oligosakarida yang lebih kecil.
Kata
kunci: Berat purata berat molekul; GPC-MALLS ;
kanji sagu; legaran jejari
REFERENCES
Ahmad,
F.B., Williams, P.A., Doublier, J.L., Durand, S. & Buleon, A. 1999.
Physico-chemical characterisation of sago starch. Carbohydrate Polymers 38:
361-370.
Al-Assaf,
S., Phillips, G.O. & Williams, P.A. 2005. Studies on acacia exudate gums.
Part I: the molecular weight of Acacia senegal gum exudates. Food
Hydrocolloids 19: 647-660.
Bello-Pe´rez,
L.A., Roger, P., Baud, B. & Colonna, P. 1998a. Macromolecular features of
starches determined by aqueous high-performance size exclusion chromatography. J.
Cereal Science 27: 267-278.
Bello-Perez,
L.A., Roger, P., Colonna, P. & Paredes-Lopez. O. 1998b. Laser light
scattering of high amylose and high amylopectin materials, stability in water
after microwave dispersion. Carbohydrate Polymers 37: 383-394.
Cornell,
H.J., Rixa, C.J. & McGraneb, S.J. 2002. Viscormetric properties of
solutions of amylose and amylopectin in aqdeous potassium thiocyanate. Starch/Strake 54: 517-526.
Fishman,
M.L. & Hoagland, P.D. 1994. Characterisation of starches dissolved in water
by microwave heating in a high pressure vessel. Carbohydrate Polymers 23:
175-183.
Gidley,
M.J. & Bulpin, P.V. 1987. Crystallization of malto-oligosaccharides as
model of the crystalline forms of starch: minimum chain length requirement for
the formation of double helices. Carbohydrate Research 161: 291-300.
Lu,
S., Chen, L.N. & Lii, C.Y. 1997. Relations between the fine structure,
physicochemical properties, and retrogradation of amylopectin from Taiwan rice
varieties. Cereal Chemistry 74: 34-39.
Millan-Testa,
C.E., Mendez-Montealvo, M.G., Ottenhof, M.-A., Farhat, I.A. & Bello-Perez,
L. A 2005. Determination of the molecular and structural characteristics of
okenia, mango, and banana starches. J. Agric. Food Chem. 53(3): 495-501.
Mua,
J.P. & Jackson, D.S. 1997. Relationships between functional attributes and
molecular structures of amylose and amylopectin fractions from corn starch. J.
Agric. Food Chem. 45(10): 3848-3854.
Praznik,
W., Huber, A., Watzinger, S. & Beck, R.H.F. 1994. Molecular characteristics
of high amylose starches. Starch/Starke 46 (3): 88-94.
Roger,
P., Bello-Perez1, L.A. & Colonna, P. 1999. Contribution of amylose and
amylopectin to the light scattering behaviour of starches in aqueous solution. Polymer 40: 6897-6909.
Sokhey,
A.S. & Chinnaswamy, R. 1993. Chemical and molecular properties of
irradiated starch extrudates. Cereal Chemistry 70(3): 260-268.
Vorwerg,
W., Radosta, S. & Leibnitz, E. 2002. Study of a preparative-scale process
for the production of amylose. Carbohydrate Polymers 47: 181-189.
Wyatt,
P. J. 1993. Light scattering and the absolute characterization of
macromolecules. Anal.
*Corresponding author; email: zainon@nuclearmalaysia.gov.my
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