Abstract:Chitosan/pectin polyelectrolyte complexes (PECs) were obtained when chitosan and pectin was mixed within 6 different kinds of ion solutions. The influences of ion type and concentration on certain characteristics such as complex yield, swelling patterns both in water and in vitro, FT-IR spectra and microstructure of the aforementioned PECs were studied. The order of ionic valence on PEC yield was trivalent ions > divalent ions > univalent ions. PEC cross-linking was promoted by the low ion concentration but prohibited by high ion concentration. The addition of FeCl3 led to a maximum in swelling degree of 56.87±0.63 in water while the minimum swelling degree of 9.21±0.13 was obtained when added with Fe2(SO4)3. The addition of MgSO4 resulted in a greatest swelling degree of 361.74±6.21, while a lowest swelling degree of 28.01±0.66 with the addition of Fe2(SO4)3 was achieved in the simulated gastro-intestinal transit solutions. FT-IR analysis indicated that ions had no effect on hybrid NH3+/COO- in PECs. SEM results showed that the chitosan/pectin PECs formed a sponge-morphic microstructure. The thickness increased from 9.76±1.03 % to 334.19±5.12%, and the layer became smooth with the interaction of ion. The porosity of PECs depended on different ions. Research showed that the addition of ions could influence the PEC complex yield, swelling ratio and microstructure, but showed little effect on PEC cross-linking pattern.
