Production of a biosurfactant from S. cerevisiae and its application in salad dressing

Abstract

Due to advances in the development of new food formulations, biosurfactants have become promising biomolecules to replace currently used compounds as well as provide improvements in the physicochemical properties of such formulations. The aim of the present study was to evaluate the effects of a biosurfactant produced by Saccharomyces cerevisiae URM 6670 added to salad dressing formulations. For the production of the biosurfactant, the yeast was cultivated (2% and 6.7% of inoculum) in media containing 1% and 3.7% of soybean waste frying oil and 1% corn steep liquor. Evaluations were performed of the biomass, pH, surface tension, and yield. After this process, emulsification activity was evaluated under different conditions of pH, temperature, and saline concentrations. The biosurfactant was then used at different concentrations and in combination with commercial emulsifiers in a salad dressing formulation. It was possible to triple the biosurfactant yield, with emulsification activity above 50% for corn, sunflower, coconut, and palm oils. Moreover, stable emulsifying activity was achieved at pH 7 and 9. The addition of the biosurfactant to salad dressing in the form of emulsions with Tween 80 and xanthan gum provided improvements in rheological parameters, demonstrating that the biosurfactant can serve as a thickener, contributing to the maintenance of the general quality of the product and improving its commercial importance.