Gelation Behaviour Of Soy Hull Pectic Polysaccharides And Preliminary Analysis Of Its Fine Structure

Soy hull pectic polysaccharide (SHPP) is extracted from soy hulls, which isone of the large bio-polymers. SHPP is a kind of hydrocolloid which willpotentially replace commercial orange pectin and pomace pectin. SHPP has theabilities of thickening, emulsification and gelatinization. At present, the study ofSHPP was confined to extraction, isolation and primary physicochemical analysis,lacking of further research, which limited SHPP utilzation in pharmacial and foodindustry, etc. This thesis firstly studied the gelation properties of SHPP deeply andsystematically, then SHPP was treated by enzymes and its fine structure wasprelininary analized, the major results were as follows:Rheological analysis was used to study external factors such as GDL, citricacid and Mg2+, which influenced the gelation of SHPP. At the same time, gelationmechanism was discussed. Results indicated that acid enhanced the gelationproperties of SHPP significantly by promoting the formation of gel and SHPP fluiddemonstrated pseudoplastic properties. Time oscillation scanning analysis showedthat hydrogen bond was the primary effort for three-dimensional structure, ionicbond and electrostatic interaction also facilitated the formation of gel.To make further improvement of strength and transparency of SHPP gel,enzymical method was adopted to restrictively modify SHPP. SHPP-P presentedNewtonian fluid properties and couldn’t form gel, SHPP-G presented the qualitiesof the dilatant fluid when sucrose concentration was above30%. SHPP-X,SHPP-M and SHPP-G solutions were still pseudoplastic fluid. The Wi of SHPP-Dand SHPP-X was19.06,5.90respectively, which showed properties of widedistribution of polymer, the Wi of SHPP-M was4.16which showed properties ofpolydispersity. The Mw of SHPP-D, SHPP-X and SHPP-M was1.099×10~5Da,1.374×10~5Da and8.034×10~5Da respectively. There weren’t significant differencesfrom monosaccharideses composition of SHPP, the molar radio of galactose togalacturonic acid of SHPP-D, SHPP-X and SHPP-M are48.63:26.55,47.74:25.82and46.30:25.06respectively. AFM analysis of SHPP-G showed that its structurewas mainly spherical. The gel sphere hardness of SHPP treated by enzyme had been significantimproved, but the transparency of gel was still poor. In order to analyze mechanismof SHPP gelation, isolation, purification, primary structure and preliminaryanalysis of space conformation were carried out. Firstly, SHPP was passed throughDEAE-Sepharose FF for the isolation and purification, then SHPP-N and SHPP-Awere obtained, afterward, IR analysis, monosaccharides analysis, LS-SEC analysis,TEM and AFM analysis was carried the two frations, results indicated thatSHPP-N mainly consisted of mannose and galactose, SHPP-A mainly consisted ofgalacturonic acid. Combination of LS and SEC demonstated the Wi of SHPP-Nand SHPP-A was1.756,1.092respectively，SHPP-A showed properties of singlescattered oligomer. The Mw of SHPP-N and SHPP-A was2.293×10~5Da and4.094×10~5Da respectively, SHPP-A was more flexibility and stretching thanSHPP-N. LS, AFM and TEM analysis showed that the structure of SHPP-A andSHPP-N were globular. The globular structure of SHPP caused poor lighttransmittance of network induced by calcium and decreased the gel transparency.