Interactions of sugar alcohol, di-saccharides and polysaccharides with polysorbate 80 as surfactant in the stabilization of foams

The interaction of different sugars with polysorbate 80 as a surfactant at foam bubble interfaces was investigated with regard to the creation of stable foams. Sorbitol, maltose, sucrose and maltodextrin DE6 were applied at concentrations of 10–60% wt. Added sugars generally resulted in a lower foam overrun, but a narrower bubble size distribution and less drainage, especially at higher viscosities. The specific overrun, however, was found to strongly depend on the type of sugar used. Sorbitol enhanced the properties of polysorbate 80 as surfactant in terms of achievable overrun. Except for sucrose, higher sugar contents close to saturation were able to minimize detectable drainage after foaming. This effect was found to depend on interactions between polysorbate 80 as surfactant with sucrose or maltodextrin as viscosity builder, which could be indirectly assessed by comparing macroscopic foam property data. Sorbitol and maltodextrin led to the most homogeneous bubble size distribution and thus, helped to create the most stable foams. According to our findings, the functions of increasing viscosity by sugars and the interfacial activity of polysorbate 80 seem to overlap or to partially compete. This knowledge is of relevance for formulating foams with the highest level of robustness, e.g. for drying processes like foam-mat or vacuum drying.