Physicochemical characterization of hemicelluloses from bamboo (Phyllostachys pubescens Mazel) stem

In this paper, hemicelluloses from bamboo (Phyllostachys pubescens Mazel) stem aged six months were sequentially extracted with hot water, 2% KOH, and 5% NaOH. The water-soluble hemicelluloses H1, and four alkali-soluble hemicellulosic fractions H2, H3, H4 and H5 were obtained, achieving a total yield of 59.60% based on the original hemicelluloses. Sugar composition analysis showed that the hemicelluloses were mainly composed of xylose (44.39–72.71%), arabinose (26.36–51.87%), ribose (0.93–2.72%), and uronic acid (0.29–5.27%). The structures of the hemicelluloses were determined to be mainly arabinoxylan, using the FT-IR and NMR techniques. The AFM images of fraction H3 revealed a distribution of spherical nanoparticles with different sizes, while the fraction H2 had helix rod and random coil feature. The SEM characterizations indicated that the fraction H1 displayed spherical particles while the fraction H3 had mainly flat particles at high magnification. Thermal stability was also analyzed using TG–DTG method and first-order kinetics model.

► Xylose and arabinose were the main components of the hemicelluloses sequentially extracted from six-month-old bamboo (Phyllostachys pubescens Mazel) stem. ► Arabinoxylans could be present as the major hemicellulosic materials. ► The morphological properties of the hemicelluloses revealed a distribution of spherical appearance or an elongated shape or flat particles.