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.