Distribution of methyl substituents over branched and linear regions in methylated starches

Autor: Ido P. Bleeker, Paul J.H.C. Mijland, Johannes F.G. Vliegenthart, Johannis P. Kamerling, Jack Bergsma, Anca van der Kerk-van Hoof, Yuri E. M. van der Burgt
Jazyk: angličtina
Rok vydání: 1998
Předmět:
Zdroj: Carbohydrate research, 312(4), 201. Elsevier
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ISSN: 0008-6215
Popis: Granular potato starch and amylopectin potato starch were methylated in aqueous suspension to molar substitutions (MS) up to 0.29. A method was developed to determine the MS of both branched and linear regions. After exhaustive digestion of the methylated starches with α -amylase, the highly branched fraction with a degree of polymerisation (DP) > 8 was separated from the linear oligomers by selective precipitation of the former in methanol. The substitution levels of branched and linear regions were determined. It was found that methylation takes place preferably at the branched regions of amylopectin and that amylose is higher substituted than linear regions of amylopectin. The distribution of methyl substituents in trimers and tetramers was determined by FABMS and compared to the outcome of a statistically random distribution. The results provided evidence for heterogeneous substituent distributions. Quantification of the degree of heterogeneity of the branched and linear regions showed a much larger deviation from random distribution in the linear regions.
Databáze: OpenAIRE
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