Fractionation and characterization of hemicelluloses from young bamboo (Phyllostachys pubescens Mazel) leaves

Bamboo leaves are considered as an important source of bioactive molecules. In this work, leaves from young bamboo (Phyllostachys pubescens Mazel) aged 3 months were subjected to aqueous extraction and 2% NaOH solution extraction followed by precipitation in ethanol-water medium with different ethanol concentrations. The dissolved hemicellulosic polysaccharides presented a total recovery of 67.83% based on the total hemicellulose content in bamboo leaves. Chemical analysis of the fractions was performed by sugar composition analysis, Fourier-transform infrared spectrometry, and 1D nuclear magnetic resonance imaging. The results revealed that all polysaccharide fractions contained xylose, arabinose, glucose, galactose, ribose, and uronic acid. The polysaccharides from young bamboo leaves mainly consisted of arabinoxylans, arabinogalactans, and non-cellulosic β-d-glucans having (1→3)- and (1→4)-glucosidic linkages. The content of these polysaccharides was found to vary among the fractions depending on the separation method. Finally, the thermal behavior was also discussed.