The invention discloses a modified
apple pectin which has a purity of higher than 90%, a methyl esterification degree of lower than 6%, an
acetylation degree of less than 2%, a molecular
linearity ofgreater than 12, and an average molecular weight of 8.0-15 kDa, and a degradation rate of higher than 90% after 12 h in the intestinal tract. The invention further discloses a preparation method of the
pectin, which comprises the following steps: uniformly mixing water and apple
powder; sequentially carrying out enzymolysis by using alpha-
amylase and the like to obtain an apple
powder enzymatic
hydrolysate, carrying out concentration and suction
filtration, and performing hot leaching on the filter residue with
acid water to obtain a crude
pectin extract; firstly adding
pectin methylesterase and pectin acetylesterase to the crude pectin extract for enzymolysis, and then adding rhamnogalacturonase and the like thereto for enzymolysis to obtain a
pectinase enzymatic
hydrolysate; subjecting the
pectinase enzymatic
hydrolysate to high-pressure dynamic micro-jet treatment before concentration, adding
ethanol to precipitate, re-dissolving the precipitate for
ultrafiltration and dialyzing, and carrying out concentration and
drying to obtain the modified
apple pectin. According to the invention, the modified
apple pectin has an increased intestinal
fermentation speed and a higher degradation rate than commodity apple pectin.