-Derived Biosurfactants: Emulsification and Antioxidant Properties in Oil Emulsions.

This study aimed to extract biosurfactants from present in traditional yogurt and evaluate their emulsifying and antioxidant performance in emulsions formed with various oils. First, yogurt samples were cultured in MRS medium, resulting in the isolation of 19 isolates (N1-N19). Morphological analyses and chemical tests on the colonies showed that seven isolates belonged to the genus. Next, hemolysis, oil spread, drop collapse, and emulsification index tests were conducted. The results indicated that none of the isolates exhibited hemolytic activity; however, isolates N4 and N18 demonstrated good performance in oil spread (8.1 ± 0.16 cm and 7.4 ± 0.04 cm, respectively) and droplet collapse (droplets with diameters larger than 1 cm) tests, also showing high emulsification index (42.49 ± 0.81 and 39.05 ± 0.32, respectively) at this stage. The two isolates, N4 and N18, were identified using PCR techniques and were named LBp_WAM and DSA LR1, respectively. Biosurfactant extraction and purification were then performed on these strains, and emulsification index, emulsion stability, and creaming index tests of the biosurfactants were conducted on emulsions formed with olive, canola, sunflower, and rice bran oils. The results showed that the biosurfactants had high emulsification index, although their effect was less than that of Tween 80. Finally, the assessment of oxidation levels indicated that the emulsions prepared with biosurfactants were significantly less oxidized compared to the control sample. The findings of this research introduce the biosurfactants derived from and as natural biosurfactants for emulsion preparation, particularly with olive and canola oils.