The Impact of Tween 20 on the Physical Properties and Structure of Agar Gel.

This study aimed to evaluate the effect of different concentrations of Tween 20 on various physical properties of agar gel as a model material. The effects of other sources of agar-agar powder on the gel properties were also evaluated. The pure gels were prepared with agar powders obtained from two suppliers. Also, agar gels with Tween 20 in the 0.10 to 0.70% range were produced. The measurement of density, water activity, maximal force at fracture and gelling temperature, and the agar gels' rheological properties, showed that the gels prepared with different agar powders had similar properties. The syneresis and stability indexes, gas hold-up, mechanical and acoustic attributes, and structure of foamed gels with Tween 20 were measured. The addition of Tween 20 in amounts ranging from 0.10 to 0.35% contributed to a gradual decrease in the stability and mechanical parameters of the gels. Using a concentration of 0.7%, Tween was able to obtain foamed gels with a uniform structure and small pore size, but low hardness and gumminess. Application of a lower concentration of Tween of 0.1% produced more rigid gels with limited gel syneresis. Adding Tween 20 at the appropriate level can be a factor in obtaining gels with a tailored structure and texture.