Abstract: 30% Fraction Hf2 of how pectin that confers the property of high viscosity to haw pectin was digested by by pectolyase. Chemical structure analysis by GLC and MS showed that Hf2 is a polygalacturonan,in which about 1/3 of the main chain is composed of (1→4)-linked GalA,and 2/3 is composed of (1→2)-linked GalA and Rha. The analysis also suggested that (1→5)-linked Arabinan and 4-O-substituted galactose,4-O-substituted mannose etc. residues should be present as side chains in the moiety of Hf2 of haw pectin.

Key words: haw, pectin, chemical structure, polygalacturonan