Relationship between foaming properties and solution properties of protein/nonionic surfactant mixtures

The foaming properties of bovine serum albumin (BSA), in the absence and pr esence of Triton X-100 (TX-100), have been investigated using shaking tests . The results showed that increases in the TX-100 bulk concentration rapidl y reduced both foam height and foam stability at TX-100 concentrations belo w about 0.25 mM, but increased foam height and foam stability at TX-100 con centration above 0.3 mM. The interaction between BSA and TX-100 has been st udied using fluorescence spectroscopy. The surfactant appeared to bind to B SA with a low molar ratio (about one surfactant molecule per protein molecu le) at concentrations below the critical micelle concentration (CMC); the b inding became weaker at concentrations above the CMC. It was confirmed that protein-protein or protein-surfactant interactions had significant influen ce upon foaming properties of mixed protein/surfactant system.