AN IMPROVED METHYLATION PROCEDURE FOR THE ANALYSIS OF COMPLEX POLYSACCHARIDES INCLUDING RESISTANT STARCH AND A CRITIQUE OF THE FACTORS WHICH LEAD TO UNDERMETHYLATION

Deficiencies in the widely used Hakomori method of methylation are des cribed. Evidence is given that this method of linkage analysis often g ives levels of undermethylation which hamper the detailed study of com plex carbohydrates from plant cell walls. A modified method using sodi um hydroxide as base is described which is capable of fully methylatin g polymers for which the Hakomori method generally fails and which doe s not promote the carbohydrate oxidation typical of a former procedure using this reagent. An explanation of its efficacy is advanced. Analy ses of retrograded, alpha-amylase-resistant starches obtained by the m odified method are reported.