THE DETERMINATION OF THE MOLECULAR-WEIGHT DISTRIBUTION OF PECTINS BY CALIBRATED GPC .2. THE UNIVERSAL CALIBRATION

Commercial high-methoxyl citrus and apple pectins were fractionated on Sepharose Cl-2B/Sepharose Cl-4B. To establish the universal calibration line, viscosity and light-scattering measurements were performed on the eluent. The angular dependencies of the scattered light were interpreted in terms of a two-component system to eliminate the contribution of particle scattering at low angles. The galacturonic acid-neutral sugar ratio within the fractions was observed by UV spectra. Results allow conclusions to be drawn on the heterogeneity of each pectin. An approach is suggested for the estimation of heterogeneity in terms of three components.