Sugar determination in ulvans by a chemical-enzymatic method coupled to high performance anion exchange chromatography

• Published in: Journal of applied phycology 1997-01, Vol.9 (2), p.179-188
• Main Authors: QUEMENER, B, LAHAYE, M, BOBIN-DUBIGEON, C
• Format: Article
• Language: English
• Subjects: Acids; Agricultural sciences; Algae; Animal, plant, fungal and microbial proteins, edible seaweeds and food yeasts; Anion exchange; Anion exchanging; Anion-exchange chromatography; Anions; Biological and medical sciences; Chromatography; Electrical measurement; Enteromorpha; Food industries; Fundamental and applied biological sciences. Psychology; Galactose; HPLC; Hydrolysates; Hydrolysis; Ion exchange; Life Sciences; Marine; Polysaccharides; Rhamnose; Saccharides; Sugar; Trifluoroacetic acid; Ulva; Xylose
• ISSN: 0921-8971; 1573-5176
• DOI: 10.1023/A:1007971023478

The sugar determination of ulvans, the water-soluble polysaccharides from Ulva sp. and Enteromorpha sp., was optimized by combining partial acid prehydrolysis (2 mol L-1 trifluoroacetic acid, 120°C) with enzymic hydrolysis (with β-D-glucuronidase). The different constitutive sugars (rhamnose, galactose, glucose, xylose, glucuronic acid), released after hydrolysis, were separated by high performance anion-exchange chromatography and determined by pulsed amperometric detection. The ulvanobiouronic acid, β-D-GlcA-(1,4)-L-Rha, which is the main constituent of ulvans was always present after 3 h of trifluoroacetic acid hydrolysis (approx. 2% D.M.) when acid hydrolysis was performed alone but the xylose amount fell to 75% of its maximum value at this time. The optimal duration of 2 mol L−1 trifluoroacetic acid hydrolysis of ulvans (i.e. without any degradation of xylose, rhamnose and glucuronic acid) was 45 min. Additionnal treatment of the partial acid hydrolysate by purified β-D-glucuronidase allowed the hydrolysis of the residual ulvanobiouronic acid in rhamnose and glucuronic acid. High performance anion exchange chromatography coupled to this chemical-enzymic hydrolysis revealed to be a high resolution chromatographic technique for monitoring the hydrolysis of the aldobiouronic acid by β-D-glucuronidase. This method allowed the simultaneous quantitative determination of neutral and acidic sugars and revealed the presence of iduronic acid inulvans.