The role of polysaccharides on the grape must ultrafiltration performance

The role of polysaccharides on the grape must ultrafiltration performance

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This work addresses ultrafiltration of grape click here must and the understanding of the membrane/polysaccharides interactions due to the chemical composition of the soluble grape must polysaccharides.The performance of two laboratory-made cellulose acetate membranes was investigated.The membranes have molecular weight cut-off of 96 kDa (CA-400-32) and 31 kDa (CA-400-28).

To identify the different polysaccharides in the fractions obtained by ultrafiltration, these molecules were isolated by dialysis, then concentrated, freeze-dried and the polysaccharide composition analysed by Gas-Chromatography with flame ionization detector after acid hydrolysis, reduction and acetylation.Polysaccharides adsorbed on the membranes were also identified and quantified by Gas-Chromatography, after hydrolysis, reduction and acetylation of the known mass of dehydrated membrane.The analysis of the membrane matrix, give evidence that mannoproteins were adsorbed on the matrix of eagles head coach hoodie CA-400-32 membrane, which has originated, in some extension, the clogging of the pores.

It was concluded that the ramnogalacturonan type II crossed the CA-400-32 membrane easily, however its depletion in the retentate and permeate streams over time may be due to its accumulation on the membrane surface, probably caused by adsorption.Arabinogalactan-proteins and mannoproteins were found in the permeate stream of the CA-400-32 membrane, whilst in the CA-400-28 membrane, ramnogalacturonan type II and the majority of arabinogalactan-proteins and mannoproteins remained in the retentate.