Butanoic acid, degradation product

Xyloisosaccharinic acid [2,4-dihydroxy-2-(hydroxymethyl)butanoic acid] is one of the major, alkaline-degradation products of wood xylan, in particular, that of birch. The disaccharide, 2-O-D-xylopyranosyl-L-arabinose, which was isolated as a hydrolysis product of corn-cob hemicellulose, is readily degraded at 100° in 15 mM Ca(OH)2 to acidic products, primarily saccharinic acids. Xylan oligosaccharides from corn-cob hemicellulose produced 2,4-dihydroxy-2-(hydroxymethyl)buta-noic acid when exposed to 0.02 M Ca(OH)2 at 25°. However, it was noted that the xylan, itself, was stable at 100° in Af NaOH. The major acidic component of the hemicellulose fraction of slash pine Pinus el-liotti) after acid hydrolysis was identified as 4-O-methyl-D-glucuronic... 

Extensive lipolysis occurs in two families of cheese in which fatty acids and/or their degradation products are major contributors to flavour, i.e. certain Italian varieties (e.g. Romano and Provolone) and the Blue cheeses. Rennet paste, which contains pre-gastric esterase (PGE) rather than rennet extract, is used in the manufacture of these Italian cheeses. PGE is highly specific for the fatty acids on the sn-3 position of glycerol, which, in the case of milk lipids, are predominantly highly flavoured short-chain fatty acids (butanoic to decanoic). These acids are principally responsible for the characteristic piquant flavour of these Italian cheeses. 

A partially degraded LAS sample will contain sulfophenyl carboxylate compounds and their cyclized desulfonation products, 1-alkyl indanones and 1-alkyl tetralones. The predominant sulfophenyl carboxylate homologs found are 3-(4-sulfophenyl)-pentanedioic acid, 4-(4-suIfophenyl)-heptanedioic acid, 3-(4-sulfophenyl)-hexanoic acid, and 3-(4-sul-fophenyl)-heptanoic acid. The monocarboxylic acids are more abundant than the dicar-boxylates (31). The most important product of fish metabolism of LAS is 3-(4-suIfophenyl)-butanoic acid (32,33). 

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