Mass spectrometry characterization of an Aloe vera mannan presenting immunostimulatory activity

► Oligosaccharides (OS) from Aloe vera polysaccharide were obtained using endo-mannanase. ► OS were analyzed by ESI-MS and MALDI-MS, by sugar and methylation analysis. ► Polysaccharide is a galactomannan with arabinose and acetyl groups as side chains. ► Acetyl groups, in an average of two per monosaccharide, were non-homogeneously distributed. ► Lower branching and higher acetylation seems to promote immunostimulatory activity.