Linkage of sugars

Every analysis performed on columns of this type (for example, carbohydrates, alcohols, organic acids, mixtures of these) can be improved with a column in the most suitable ionic form, even though solutions with compounds of differing types may impose the choice of a compromise. In analytical practice, however, it is not advisable to make an in-column conversion from one form to another, for the resin could shrink or even swell in relation to the type of cation linked. The effect of fixed-cation is made obvious when the compounds under analysis can coordinate with it, as in the case of carbohydrates. For example, the linkage of sugars with three adjacent hydroxyls may be more stable than those that have only two, with obvious effects in the resolution of the analytes. Finally, it is advisable to use a guard column to prolong the life of the... 

XII or XIII, it is reasonable to assume that the xylan backbone is unbranched. In the case, however, of xylans containing L-arabinofuranose residues, it is much more difficult to obtain direct evidence for the order of linkage of sugar residues. It is doubtful if it would be possible by present methods to detect a small proportion of L-arabinofuranose residues terminating main xylan chains (as in XIV) if these residues were also attached as side-chains (I), as commonly found. 

The positions, numbers, and types of sugars on the anthocyanin molecule influence its bioaccessibility. Indeed, a recent human study reported that the acylation of anthocyaifins resulted in a sigififlcant decrease of anthocyanin recoveries in plasma and urine. In addition, anthocyanins form linkages with aromatic acids, aliphatic acids, and methyl ester derivatives, which can also affect their passage through the intestinal barrier. 

Rearrangement of Sugar-Sugar Orthoesters Leading to 1,2-cu-Glycosidic Linkages... 

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