Pomelo (Citrus maxima) pectin: Effects of extraction parameters and its properties

At present, the available information on recovery of pectin from pomelo peel is still limited. Moreover, the extraction parameters depend on the raw material and the preferred functional properties of the pectin. Therefore, in this study, pomelo pectin extraction parameters affecting pectin yield and its properties were investigated by the single factor and central composite design methods. It was found that pH played an important role in controlling pectin yield and its side chain composition, particularly arabinose and galactose. In addition, it is worth pointing out that the neutral polysaccharide side chains of the extracted pomelo pectin mainly consisted of arabinose instead of galactose which was typically found as a principal neutral sugar in those of citrus and apple pectins. Apart from pH, the extraction temperature also showed strong influence on the yield and molecular weight (MW), but not on the degree of esterification (DE). Under the suggested optimal condition, the pectin yield was measured to be 23.19% and its DE and MW values were approximately 57.87% and 353 kDa, respectively. Rheological experiments showed that the pomelo pectin dispersions behaved as a viscoelastic solution below 1%w/v and formed a weak gel network at higher concentrations. In addition, the flow behavior of the dispersions below 0.4 %w/v was Newtonian but they exhibited a pseudoplastic with shear thinning characteristic at higher concentrations.