Gelation behaviors of the konjac gum from different origins: A.guripingensis and A.rivirei

Thermal irreversible gel is one of the important application forms of konjac gum in the food industry. The gelation behaviors of the gum from A.guripingensis were investigated in comparison with that from A.rivirei in order to explore the potential application of this new source of konjac gum. The concentration of konjac gum, content of alkali, and temperature were found to be the main factors influencing the gel properties. Compared with the gel prepared from A.rivirei gum (ARG), the gel prepared from A.guripingensis gum (AGG) possessed higher breaking forces under the same conditions. Rheology was used to monitor the dynamic gelation process, representing the sol-gel transition of konjac gum aqueous dispersions. Rheology result indicated that crossover point of G′ and G″ existed at relatively low konjac gum concentration, alkali content or temperature for ARG, however, G′ of AGG was always higher than G″. The chemical structural change was observed, demonstrating that the deacetylation was accompanied with the gelation process. Crystallinity and morphology of konjac gels were also studied. These results indicated that the konjac gum from various sources showed distinct differences in gelation behaviors. Compared to ARG, AGG showed better gel-forming ability since lower concentration and temperature, or less content of alkali was required for its gelation. • The gelation behaviors of konjac gums from two species showed distinct differences. • A.guripingensis gum (AGG) gel possessed higher breaking force than that of A.rivirei gum (ARG) gel under the same conditions. • AGG required lower concentration, temperature and less alkali content to form a gel compared to ARG. • FT-IR analysis showed that the deacetylation was accompanied with the gelation process.