苹果梨果胶理化特性的研究

Physico-chemical Properties of Pingguoli Pear Pectin

采用酸解法从苹果梨疏果和成熟果榨汁后的果渣中提取果胶,并对果胶纯度、色度、甲氧基含量、酯化度、黏度和相对分子质量进行测定。结果表明:用酸解法结合沉析法提纯的苹果梨果胶纯度在70%以上,疏果期果胶颜色为浅棕色,成熟期果胶颜色为白色。苹果梨成熟期果胶的特性黏度和相对分子质量分别为1.51×10-7Pa·s和6.96×105,均高于疏果期果胶,两者均为高酯果胶,其中疏果期果胶为慢凝型果胶,成熟期果胶为速凝型果胶。

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 6.96×10^5,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.