| Apple pomace which was produced by Meixian plant, Shaanxi Hengxing Fruit Juice Company LTD. was collected in third tenth of August and employed to prepare polysaccharides with either step-extracting or acidic-extracting/pectin preparation technology. 5 Half-pure polysaccharides WMPP, HAMPP, HAMPP', SHMPP, HAMPPE were yielded. Based on the successful results of protein removal and decolor method, the isolation and purification of Apple Polysaccharide extracted with each processing technology with chromatography, DPPH·scanvaging activity as well as FTIR spectrum were measured and analysised. All results showed as following:(1) TCA precipitation with 3-time repeats was selected the best among 4 methods for removing protein, which gave protein removal rate 23.87%, while the rate of polysaccharide loss is only 0.40%. Secondly, dialysis is selected as suitable method for decoloring the extracts.(2) Isolated and purified by the chromatography of TOYOPEARL DEAE-650M, followed by TOYOPEARL HW-55F column, three compositions of WMPP1, WMPP2 and WMPP3 were harvested from WMPP, the yield of which was 72, 312.6 and 80.2g/kg, respectively; three compositions of HAMPP1, HAMPP2 and HAMPP3 were also harvested from HAMPP, the yield of which was 367.6,176.2 and 79.7g/kg respectively; In the same way, three compositions of HAMPP'1, HAMPP'2 and HAMPP'3 from HAMPP'were yielded 141.4,237.4 and 101.3g/kg respectively; three compositions of HAMPPE1, HAMPPE2, and HAMPPE3 from HAMPPE, were yielded 190.1,314.2 and 73.7 g/kg respectively.(3) The WMPP, HAMPP and HAMPPE and each of their pure composition all showed DPPH·-scavenging capacity (SA). Within certain range of concentration, dose-effect relationship displayed.(4) The half inhibitory concentration (IC50 ) for DPPH·-scavenging of WMPP and its three compositions of WMPP1, WMPP2 and WMPP3 is 2mg/mL,3.6 mg/mL,10mg/mL and 4.8mg/mL respectively. The lowest IC50 of WMPP indicates the stongest scavenging capacity it has, WMPP1 goes the next, WMPP3 goes the third and WMPP2 is the lowest. (5) The half inhibitory concentration (IC50 ) for DPPH·-scavenging of HAMPP and its three compositions of HAMPP1, HAMPP2 and HAMPP3 is 1.7mg/mL,3.4 mg/mL,6.9mg/mL and 5mg/mL respectively. The lowest IC50 of HAMPP indicates its strongest scavenging capacity. HAMPP1 goes the next, HAMPP3 goes the third and HAMPP2 is the lowest.(6) The half inhibitory concentration (IC50) for DPPH·-scavenging of HAMPP'and its three compositions of HAMPP'1, HAMPP'2 and HAMPP'3 is 0.6mg/mL,0.5 mg/mL,4.6mg/mL and 4.9mg/mL respectively. The lowest IC50 of HAMPP'1 indicates its strongest scavenging capacity. HAMPP'goes the next, HAMPP'2 goes the third and HAMPP'3 is the lowest.(7) The half inhibitory concentration (IC50 ) for DPPH·-scavenging of HAMPPE and its three compositions of HAMPPE1, HAMPPE2 and HAMPPE3 is 4.4mg/mL,5.5mg/mL,11mg/mL and 8.4mg/mL respectively, which indicates the DPPH·scavenging capacity decrease in turns of HAMPPE, HAMPPE1, HAMPPE3, HAMPPE2.(8) The FTIR spectrum of each purified product all displayed structural characteristics of polysaccharide. Besides, WMPP1 shows the characteristic absorption peak of acidamide. So WMPP1 is probably a glucidamin consisted ofα-,β- D-mannopyranose andα-xylose; WMPP2 is also a glucidamin but consisted of D-glucopyranose andα-D-xylopyranose; WMPP3 has a much simplified composition mainly composed ofα-D- xylopyranose.(9) The FTIR spectrum of three compositions from HAMPP and three compositions from HAMPP'resember quit well, which indicated that their composition 2 are the same acidic polysaccharose consisted ofα,β- mannose andβ-D-glucopyranose andα-D- xylopyranose; composition 3 is also an acidic polysaccharose containingβ-D-mannose,α-D -galactopyranose,β-D- glucopyranose andα-D- xylopyranose; Composition1 is a glucidamin mainly containing fructofuranose andα-D-xylopyranose with a compound-protein composition, which accounted for their high DPPH·-scavenging activity.(10) The FTIR spectrum of the three compositions of HAMPPE shows that they are all acidic polysaccharose consisted ofα,β-D-mannose,β-D-glucopyranose andα-D- xylopyranose, but they have differences on molecular weight and the ratio of monosaccharide.
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