Progressive dissociation of pectin

The structural organization of alkaline soluble peach pectin was investigated over size ranges extending from micrometers to tenths of nanometers. Analysis was by electron microscopy and high-performance anion-exchange chromatography (HPAEC). Superimposed and individual circular microgels in the micrometer size range were isolated from mesocarp tissue of cell walls and visualized by rotary shadowing. Dilute NaCl and 50% aqueous glycerol disaggregated these microgels into rods, segmented rods, and kinked rods, which collectively comprised the internal gel network of the microgels. Image analysis of the shadowed specimens before and after disaggregation followed by curve fitting of the smoothed distributions revealed a multimodal distribution of lengths. HPAEC revealed that the multimodal aggregates were stable for the most part to further dissociation by increasing ionic strength.