Two fractions (permeate and retentate) from fiber-free Aloe vera gel were separated using ultra-filtration (UF) system with tubular ceramic membrane (MWCO of 50 kDa), and their molecular properties were investigated. The retentate of UF Aloe gel was a polysaccharide-rich fraction containing about 2.3-fold higher polysaccharide content than fiber-free gel. The FT-IR and 1H NMR spectra of this fraction showed the characteristic patterns of β-binding polysaccharide and a higher degree of acetylation indicating a higher level of bioactive polysaccharide content. The
molecular weight and polydispersity of polysaccharide fraction from GPC (gel permeation chromatography) were determined to be 36.8-43.9 kDa and 1.24, respectively, indicating a kind of undispersed polysaccharide. From the SEM observation, the surface structure of polysaccharide fraction had a gel cluster-like structure with a convoluted rough surface. The molecular conformation by Congo red assay exhibited a property of helix structure confirming the existence of a higher-ordered structure as a biological activity conformation.