Abstract:The influences of different factors on the complex coacervates of corn arabinoxylan (CAX) and chitosan (CS) were investigated and the conditions for the formation of arabinoxylan/chitosan complexes were determined by measuring the turbidity at equilibrium and the complex coacervate yield obtained by precipitation. Complex coacervates were characterized using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis, scanning electron microscopy (SEM), and rheological properties. A maximum complex coacervate yield of 76.04 % was obtained under the optimum conditions of an arabinoxylan/chitosan mass ratio of 9:1, total biopolymer concentration of 3 % (m/m), pH of 4.0, the room temperature, and reaction time of 10 min. FTIR and thermogravimetric analysis results suggested that complex coacervates are formed via electrostatic interactions between the CS amine group (-NH3+) and the CAX carboxyl group (-COO-). SEM micrographs revealed a regular and uniformly distributed porous network structure for the complex coacervates. Viscoelastic properties of CAX/CS complex coacervates depend on the coacervation pH, with coacervates formed at pH 3.5 and 4.0 showing liquid viscoelastic behavior and those formed at pH 5.0 exhibiting solid viscoelastic behavior. The coacervates formed at pH 5.0 had the highest elastic modulus, implying that factors other than electrostatic interaction are important in the viscoelastic properties. The results indicate that CAX/CS coacervates can be applied for the encapsulation of nutrients and other functional factors.
