Effect of sodium alginate on freeze-thaw stability of deacetylated konjac glucomannan gel

Freeze-thaw stability improvement of deacetylated konjac glucomannan (DKGM) gel is a challenge. This study explored the effect of sodium alginate on the water-holding capacity, texture, rheological properties, crystallinity, microstructure and other properties of DKGM gel after 0, 1, 3, and 5 freeze-thaw cycles. Sodium alginate significantly enhanced the water-holding capacity of DKGM gel and mitigated the damage to gel viscoelastic properties caused by freeze-thaw cycles. Additionally, sodium alginate attenuated this phenomenon that the freeze-thaw process resulted in an increase in the intensity of the -OH absorption peak in the gel. Sodium alginate also decreased the hardness, crystallinity, eutectic point, and freezable water content of the DKGM gel. Finally, it prompted the development of a denser microstructure in the gel, thereby stabilizing the composite gel during freezing and thawing. These positive effects were attributed to the interactions between water molecules and polysaccharides in the gel, resulting in enhanced hydrogen bonding and intermolecular forces. These findings highlight the potential of cost-effective sodium alginate in augmenting the freeze-thaw stability of DKGM hydrogel.