Effect of gamma-irradiation on degradation of alginate.
The aqueous solution of alginate was irradiated by 60Co gamma-rays in the dose range of 10-500 kGy. To assess the effect of irradiation on the degradation of alginate, the irradiation-induced changes in the viscosity, molecular weight, color, monomer composition, and sequence were measured. The molecular weight of raw alginate was reduced from 300000 to 25000 when irradiated at 100 kGy. The degradation rate decreased and the chain breaks per molecule increased with increasing irradiation dose. The viscosity of irradiated alginate solution reached a near minimum as low as at 10 kGy. No appreciable color changes were observed in the samples irradiated at up to 100 kGy, but intense browning occurred beyond 200 kGy. The 13C NMR spectra showed that homopolymeric blocks, MM and GG, increased and the M/G ratio decreased with irradiation. Considering both the level of degradation and the color change of alginate, the optimum irradiation dose was found to be 100 kGy.
Lee
Dong Wook
DW
Graduate School of Biotechnology, Korea University, Seoul 136-701, Korea.
Choi
Won Seok
WS
Byun
Myung Woo
MW
Park
Hyun Jin
HJ
Yu
Yong-Man
YM
Lee
Chong M
CM
D000464:Alginates / Q000737:chemistry* / Q000528:radiation effects*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003037:Cobalt Radioisotopes; D003116:Color; D005720:Gamma Rays; D020723:Glucuronic Acid / Q000737:chemistry* / Q000528:radiation effects*; D006603:Hexuronic Acids / Q000737:chemistry* / Q000528:radiation effects*; D009682:Magnetic Resonance Spectroscopy; D008970:Molecular Weight; D014783:Viscosity
D000464:Alginates; D003037:Cobalt Radioisotopes; D006603:Hexuronic Acids; D020723:Glucuronic Acid