Glucomannan acid hydrolysis

Similarly, the a-D-( 1-6)-galactosidic linkage present in galactoglucoman-nans is very labile under acidic conditions [262]. Its high reactivity, however, cannot be satisfactorily explained in terms of the behavior of simple glycosides (Table 2). Alkali-induced deacetylation of glucomannan increased its resistance toward acid hydrolysis as evidenced in acid sulfite cooking [263,264]. 

Rha), arabinose (Ara), galactose (Gal), xylose (Xyl), and 4-O-methyl-glucuronic acid (M-GluU) are the same or larger than after intensive hydrolysis, evidence for a more moderate action of the acid. But for a complete hydrolysis of cellulose and glucomannan, the moderate method is not sufficient therefore, the peaks for mannose (Man) and glucose (Glu) are much smaller after this treatment. 

Alkali-induced deacetylation and hydrolysis of the uronic acid group of xylans proceed readily under alkaline pulping conditions and contribute significantly to xylan redeposition onto the fibers. The galactose side chain in galactoglucomannans is fairly resistant to alkaline hydrolysis (Table 2). Wood xylans are much more stable than glucomannans under alkaline conditions [34]. 

Oligosaccharides (d.p. 4-8) prepared by hydrolysis of galacto-P(l-4)glucomannan were inhibitors at 10-4 to lOpM of hormonal stimulated elongation of pea stem segments, and also affected the viability of spruce embryos on media supplemented with indole-3-acetic acid zeatin [81]. 

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