Abstract:

Acid hydrolysis was used to extract Pingguoli pear pectin from young fruits and pomace of matured fruits after juicing and the crude extract was then purified by absolute ethanol precipitation method. The purity colour, methoxy content, esterification degree, intrinsic viscosity and molecular mass of Pingguoli pear pectin were determined. The purity of the purified Pingguoli pear pectin was more than 70%. The color of the pectin from young and matured fruits was light brown and white, respectively. The intrinsic viscosity and molecular mass of the pectin from matured fruits were 1.51×10-7Pa·s and 6.96×105, which were both higher than those of the pectin from young fruits. However, both kinds of pectin were high methoxyl (HM) pectin. The pectin from young fruits was slow-setting pectin and the pectin from matured fruits was rapid-setting pectin.

Key words: Pingguoli pear, pectin, purity, colour of pectins, methoxy content, esterification degree, intrinsic viscosity, molecular mass