Studies on uronic acid materials. Part XV. The use of molecular-sieve chromatography in studies on acacia senegal gum (gum arabic)

Investigations involving fractional precipitation of A. senegal gum by sodium sulphate lead to a discussion on the type of heterogeneity exhibited by the gum. Molecular-sieve chromatography is used to estimate number-average molecular weights. Results obtained using this chromatographic technique on the degraded gum produced on autohydrolysis indicate that such mild conditions of hydrolysis are not always very selective as a means of degradation. The degraded gum is shown to have galactose residues as reducing end-groups. There is no evidence for labile, internal, arabinofuranosyl linkages in the whole gum. In addition, chromatographic evidence is obtained for the presence of 6-O-(4-O-methyl-β-D-glucopyranosyluronic acid)-D-galactose residues in A. senegal gum.