Influence of alkaline treatments and pretreatments in hemicellulose preparation.

THE method for the preparation of hemicelluloses originally proposed by Norris & Preece [1930] involves a preliminary treatment of the tissue material with 0-5 % ammonium oxalate solution for the removal of pectin and water-soluble substances followed by treatment with boiling 50 % ethyl alcohol-i % NaOH solution with the intention of diminishing contamination of the subsequent preparation with lignin. Hemicelluloses are then removed from the residue by solution in 4 % aqueous NaOH. to from structural dilute