Comparative polarographic study of the acid hydrolysis of some sugars

Abstract

The possibility of obtaining not only qualitative, but also quantitative results induced us to study the characteristics of the acid hydrolysis of saccharose, rafinose and melicitose. We have used 0.5 mM water Solutions of the sugars, with 0,05 HC1, at the ordinary temperature (15 to 10 degrees) A determination at time 0 in all cases gave no reduction waves, and was used as control.

The convenience of using lithium chloride as a ≪background≪ solution induced us to neutralize the C1H, with lithium hydroxide.

Determinations were made at 0, 24, 48 and 72 hours for the saccharose and rafinose, and up to 144, every 24 hours, for the melicitose. The rafinose and saccharose show an almost total hydrolysis at 72 hours. On the contrary this has hardly begun in melicitose at the same time, and after 6 days, the fructose produced from it is approximately 50 % of that which appears at 72 hours in the hydrolysis of rafinose and saccharose.

In spite of the different Chemical composition, the hydrolysis rate of saccharose and rafinose is the same, as far as the release of molecules of fructose is concerned, perhaps because the saccharose has a structure completely similar to one of the extremes of the trisaccharide rafinose. On the other hand, the melicitose shows a much lower rate of fructose release, as the fructose occupies a central position in this trisaccharide.