For chemical characterization, dried SCG was subjected to a
quantitative acid hydrolysis with 72% (w/w) sulfuric acid. In this
method, 2 g of sample were first added to 10 ml 72% H2SO4 and
maintained at 50 ◦C for 7 min. After this pre-treatment, distilled
water was added to the mixture to dilute the H2SO4 to 1N, and incubated
at 121 ◦C for 45 min. The monosaccharides and acetic acid
contained in hydrolysates were determined by HPLC in order to
estimate the contents of samples in cellulose (as glucan), hemicellulose
(as mannan + galactan + arabinan + xylan) and acetyl groups.
Protein content was estimated by the Kjeldahl nitrogen method,
and a factor of 6.25 was used to convert nitrogen into protein. Ashes
were determined by weight difference before and after incineration
of the SCG sample in a muffle furnace at 550 ◦C for 4 h. Before
weighing, samples were placed in a desiccator for 50 min. The mineral
content was determined by Inductively Coupled Plasma Atomic
Emission Spectrometry (ICP-AES). All determinations were carried