Possibilities for the specific reduction of fructose

Abstract

The aim of this work was to investigate the application of boronic acids for the specific reduction of fructose in food matrices as fruit juice. The ability of boronic acids to form esters with diol structures forms the basis of the investigation. The retention of fruit juice components in a solution and fruit juice was analysed on a boronic acid gel. The known affinity decrease in boronic acid in the order of sorbitol, fructose, galactose and glucose was confirmed. The disaccharides sucrose and maltose as well as the fruit acids malic acid, citric acid and tartaric acid have not shown any interactions. The ligand 3-aminophenylboronic acid was appropriate for the reversible binding of fructose at higher pH values. The sugar reduction and the change of the sugar composition were possible by fractionation. For the application in the natural pH range of a fruit juice, specific substituted boronic acids (3-fluoro-5-methoxycarbonylphenylboronic acid, 3-carboxy-5-nitrophenylboronic acid and 3-methoxy-5-nitrophenylboronic acid) were analysed concerning an interaction with fructose. The spectroscopy in the UV range was appropriate as a method of detection. The 3-carboxy-5-nitrophenylboronic acid is a possible ligand for applications in acid media. In brief, this paper shows the potential of boronic acids for a specific reduction of fructose in food matrices.