| Pectic substances from eleven samples of dried apple pomace were extracted using an acid procedure (100 mM HNO3, 10 min., 80ºC), dried, ground and stored in a P2O5 atmosphere. The degree of esterification was determined by the classical titrimetric method and confirmed by the instrumental FTIR method. The samples showed an average DE of 73% and the typical fingerprint in IR spectrogram. The steric exclusion chromatograms obtained with the multi-angle laser light scattering (MALLS) and refraction index (RI) detectors showed that all samples had a high molar fraction eluted at 36-38 min., another large polysaccharide family had an elution time around 43 min, and some samples showed yet another low molecular oligosaccharide that appeared at 58-60 min. Gas... |
