MODIFIED PROCEDURES FOR EXTRACTION AND ANALYSIS OF CARRAGEENAN APPLIED TO THE RED ALGA HYPNEA-MUSCIFORMIS

Dried powder of Hypnea musciformis was extracted with water at pH 7 af ter an initial short pre-treatment with cold, diluted HCl. Carrageenan s were isolated by alcohol precipitation after an amylase treatment an d a filtration of the extracts. The yields at 25 and 90 degrees C were 25 and 75% (w/w) of the dry alga, with molecular weights (Mw) corresp onding to 194 000 and 245 000, respectively. The chemical structure wa s dominated by G4S-DA-(kappa-carrageenan or carrageenose 4'-sulphate). A simple fractionation procedure for kappa-carrageenase hydrolysates, based on stirring in different enthanol/water mixtures, is introduced . NMR analysis showed that oligosaccharides with a repeating DA-G4S st ructure were the main constituents in the enzymic hydrolysates of the carrageenans from Hypnea musciformis. These oligosaccharides were solu bilized in an ethanol concentration from 96 to 48% (v/v). In some enzy me resistant fractions D6S-G4S and DA2S-G4S sequences and D2S,6S unite s were detected by C-13-NMR.