Isolation and physicochemical characterisation of xylose-rich pectic polysaccharide from wheat straw

Xylose-rich pectic polysaccharide (XRPP) was extracted from defatted and protein-free wheat straw with a solution adjusted to pH 1.6 using hydrochloric acid (HCl). The yield of XRPP obtained was 1.1% of the dried wheat straw. The isolated XRPP contained 44.8% galacturonic acid released by pectolyase treatment and 32.1% released by 2 N trifluoroacetic acid hydrolysis. The XRPP also contained 17.1 % neutral sugars released by pectinase reaction and 28.4% released by the acid hydrolysis. A comparison of the FT-IR spectroscopic data of citrus pectin and XRPP showed that the extracted XRPP belongs to pectic substances and differs from hemicellulose with an intensive absorption band at 1740 cm(-1).