The composition of sunflower stalks is summarized in Table 1
and agrees well with that previously reported although lignin content
is lower [5,6]. Hemicellulosic sugars accounts for 20.7% of the
raw material dry weight with xylose as the main sugar (73%). Acetyl
groups, bound through an ester linkage to branched hemicellulose
chains, represent about 2.1% of the raw material. Regarding
extractive content, the first extraction step, with water, dissolved
15.96 ± 1.01% of the raw material while the ethanol extraction step
dissolved 0.45 ± 0.09% of the material.