Effect and characterization of konjac glucomannan on xanthan gum/κ-carrageenan/agar system

A mixed polysaccharide system is an important strategy to improve the performance of a single polysaccharide. Herein, quaternary polysaccharide gels were prepared by konjac glucomannan (KGM), xanthan gum (XG), κ-carrageenan (κ-CA), and agar (AR). The effects of KGM were evaluated by combining water holding capacity (WHC), rheological analysis, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and texture profile analysis (TPA). More KGM gradually increased the springiness of the compounded gels. WHC increased and then decreased with the addition of KGM, performing best at KGM4 (KGM: κ-CA:XG:AR = 2:2:1:2). Rheological analysis showed that the compounded gels exhibited a pseudoplastic characteristic of shear thinning, KGM endowed the gel with a stronger shear thinning behavior and improved the solid-like nature of the gels at high temperatures. The thermal stability of the composite gel was improved by the participation of KGM. FTIR analysis showed that the interactions were mainly related to intermolecular hydrogen bonds and acetyl groups. The microscopic morphology of KGM4 was significantly continuous, smooth, and compact, exhibiting the best practical performance and taking the maximum advantage.