Biophysical characterisation of hydrophobin enriched foamate

Food industries are interested in finding highly stable foaming agents for product texture improvements. Hydrophobins have been mentioned many times in that context. For the production and purification of hydrophobin HFBII from Trichoderma reesei we found that foam fractionation of the fungal fermentation media is an interesting first step. After this step, the biophysical properties of the obtained foamate were studied. The foam generated by CO₂ as the only sparging gas into a HFBII enriched solution in a closed environment was more stable than the foam generated by sparging with air. The equilibrium surface tension of a foamate containing 100 mg/L HFBII was measured by CAMTEL CDCA-100 tensiometry as equal to 40 mJ/m², and was confirmed by the maximum bubble pressure tensiometer. Besides, it was found that for a long term foam preservation, the foam created by the HFBII-SDS combination is more stable than that of SDS.