| The mature De-seeded Sunflower Heads (Helianthus annuus) was extracted byacidic, alkaline and water extractions yielding to four polysaccharidesAHP-01,AHP-0.2(oxalic acid0.1%and0.2%extracted polysaccharide, respectively), BHP(alkaline extracted polysaccharide) and WHP (water extracted polysaccharide) with ayield of10%,18.14%,17.9%and8%, respectively.The high performance liquid chromatography (HPLC) experiment revealedthatthere was an obvious variation among the monosaccharide compositions of thesecrude polysaccharides.BHP was further fractionated into BHPS (soluble fraction) and BHPP(insolublefraction) by freeze-thawing process. BHPS was then purified by gel-permeationchromatography (GPC) resulted in five fractions (BHPS-I, BHPS-II, BHPS-III,BHPS-IV and BHPS-V).The high performance gel-permeation chromatography(HPGPC) analysis revealed that these five fractions are homogeneous and theirmolecular weight (Mw) were estimated to be BHPS-I (544kDa), BHPS-II (428kDa),BHPS-III (134kDa), BHPS-IV (96kDa) and BHPS-V (67kDa). The FT-IR analysisspectra of the respective fractionsshowed that no absorption signals were detected inthe region band of methyl-esters.BHPS-I, BHPS-III and BHPS-IV were mainly consisted of Rha (33.35%,31.31%and31.32%, respectively), GalA (27.11%,10.36%and11.65%,respectively)and Gal (26.84%,35.4%and31.82%, respectively) with small amountsof GlcA, Glc, Man, Ara and Xyl. While BHPS-II and BHPS-V were mainly composedof Xyl (37.04%and36.23%, respectively), Gal (16.99%and21.74%, respectively),GalA (10.35%and11.3%, respectively) and Rha (19.43%and8.68%, respectively)with small amounts of GlcA, Man and Ara. It could thus be concluded that BHPS-I,BHPS-III and BHPS-IV might be rhamnogalacturonan-and homogalacturonan-typepectins; while BHPS-II and BHPS-V might be xylose-rich pectins containingxylogalacturonans that so far have not been reported as characterized insunflower.Our study provided some data for a better understanding of Helianthusannuuspolysaccharides. |
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