Stabilization of casein-based gels by oxidized konjac glucomannan: the role of ozone generation times

The increased demand for dairy products, such as yogurt and cheese, presents new challenges for their development. However, the instability of casein (CS) under acidic conditions limits the development of highly stable dairy products. Polysaccharides could be used to construct CS gel networks, thereby affecting the gel properties and improving the texture of dairy products. Based on this, the study investigated the effects of oxidized konjac glucomannan (OKGM) with different ozone generation times (OGT, 0, 30, 60, 90, and 120 min) on the properties of gluconolactone (GDL)-induced CS gels. The results revealed that the network structure of composite gels was enhanced with increasing OGT of OKGM. The OKGM (OGT over 30 min) enhanced the water-holding capacity and viscoelasticity of the gel, resulting in an orderly gel matrix. In addition, the enhanced hydrophobic and disulfide bond interactions within the composite gel accelerated gel formation and reduced the gelation time from 46.32 ± 0.18 min to 27.79 ± 0.18 min. Conversely, native KGM and OKGM obtained at OGT of 30 min resulted in depletion flocculation of the gel due to the exclusion volume effect. Overall, OKGM with longer OGT served as a potential stabilizer for gel products. This possibility implies that it may be applied in the food industry, offering inspiration for the creation of innovative, highly stable fermented milk products.