Extraction And Physicochemical Characterization Of Chicory Root Pulp Pectin

Chicory pulp, the by-product of chicory industry, is a potential source ofpectin manufacturing. In order to add value to the chicory industry, the extraction ofchicory pulp pectin has been studied. Effects of raw material pretreatment, acidextraction medium, type of extraction agents and alcoholic-precipitation conditions onthe characterization of pectin were investigated. Conculsions were submitted asfollow:1. The hot water pretreatment procedure (80℃，1h) effectively removed thewater-soluble polysaccharides consisting of35.49%GalA,25.6%neutral sugar,5.84%protein and6.52%ash. The weight-average molar mass value (769.1kg/mol)of this part of polysaccharides is notably high, suggesting that the major content ofthis portion is non-pectic substance. The pretreatment can remove the macromolecularsubstance, netural sugar and ash inside the chicory pulp.2. The extraction of pectins in an aqueous acid medium from chicory root pulpwas carried out under different conditions using a full two–state experimental designfor three extraction parameters (pH, temperature and time). The yields of the extractedpectins varied from4.8%to12.4%. Their contents in pectin constituents were60.3–78.0%galacturonic acid,14.6%–26.5%neutral sugars,38.1%–66.9%degree ofmethylation,4.5%–10.3%degree of acethylation. Moreover, protein residues werepresent in all the extracts within the range of1.7%–6.6%and varied with theextraction conditions. Their weight-average molar mass values determined bySEC-MASL ranged widely from131kDa–396kDa. The molar mass distribution ofchicory root pulp pectin at different extracted condition exhibited the similar narrowpattern. The full two–state experimental design showed the extracted time hadsignificant influence on yield, DM and the content of GalA, Rha and Ara, meanwhile,the pH had a significant influence on DM as well. By considering all results, the acidextraction of chicory root pulp pectin at90℃, at pH1.5for4h could be suitable.3. Chicory pulp pectin was extracted by hydrochloric acid (HEP), ammoniumoxalate (AOP) and sodium hexametaphosphate (SHP). HEP and AOP had high GalA contents, but relatively low degree of esterification and acetylation. The ash content ofSHP excessed42.02%, which can be decreased effectively via adjusting the pH ofextraction or washing the pectin with acid-ethanol. Their weight-average molar massvalues determined by SEC-MASL varied from190.2to396.5kg/mol. The gelationtest showed that only the AOP geled without the presence of exogenous calcium ions.4. Chicory pectins with different structural characterization (yield, compositionand weight-average molar mass values) were precipitated under various conditions.To precipitate by importing the liquid to the ethanol (LTE) can enhance the yield,content of GalA and weight-average molar mass values of HEP and AOP, but it willdiversify the composition of them. The weight-average molar mass values of HEP,AOP and SHP showed different trend when the volume of precipitation increase, butmore ethanol will enhance their yield, content of GalA and netural sugar consistently.The maximum yield and content of GalA were both obtained when the precipitationpH is3.5.5. HEP and SHP solution behaved as the Newtonain fluid at low concentration,and it turned to behave shear thinning when the concentration increased, the viscosityof SHP solution was higher than HEP’s at the same concentration. The strain-sweeptest showed that the linear viscoelastic manner region is0-0.1%, and the elasticmodulus G’ is lower than viscous modulus G’’ when the strain was over1%. Thestrain temperature sweep indicate the gelling temperature of AOP is70℃.