2002 Volume 8 Issue 2 Pages 172-177
The effectiveness of a membrane process combining ultrafiltration (UF) and nanofiltration (NF) for purifying and concentrating non-digestible saccharides (NDS) from yacon rootstock was examined. The yacon rootstock used as experimental material contains, among various other agromaterials, a comparatively large amount of NDS, fructooligosaccharide (FOS) and inulopolysaccharide. After extraction with hot water followed by UF clarification and NF purification processes, the resulting NF retentate containing NDS in high concentration was obtained as a 25-fold concentrated product. NDS purity was ultimately raised from 81% to 98% by the combined membrane processes of UF and NF (with G10 membrane). HPLC analysis revealed that the NF membranes had specificity of rejection for saccharides of particular degrees of polymerization (DP). The rejection performance remained constant throughout the NF process. On the whole, the results indicate that the combined membrane-processing system is quite promising for value-added products using purified concentrate of NDS.
