Ultrasonic extraction of plant materials-investigation of hemicellulose release from buckwheat hulls

Various one- and two-step extraction procedures with and without a short application of ultrasound at the beginning of the extraction were used to examine the effect of sonication on the extractibility of the hemicellulose components of buckwheat hulls. The polysaccharides recovered from the extracts were characterised by yield as well as composition determined by chemical methods and spectroscopic techniques. They comprised a complex of glucuronoxylan and co-extracted amylose-rich starch in various proportions contaminated with other cell wall components (protein, pectic polysaccharides). The hemicellulose fractions obtained by classical and ultrasound-assisted extraction exhibited significant immunomodulatory activities. The increased yield of ultrasonically extracted hemicelluloses, which have preserved their structural and molecular properties as well as immunological activity, confirmed the importance and great potential of ultrasound-assisted extraction of industrially important polysaccharides from different tissues of plant materials. (C) 2003 Elsevier Science B.V. All rights reserved.