## 3 Results
### Emulsification Activity  
The emulsification properties of the extracts from _G. max_ and _C. quinoa_ using grape seed and sweet almond oils were assessed to determine the stability of the solutions of the purified biosurfactants containing these oils when submitted to extreme variations in temperature, pH, and salinity. Figure 2 illustrates the activity of the emulsions of the _G. max_ biosurfactant when exposed to changes in temperature for 24 h and in concentration (% CMC, CMC, and 2 CMC). The biosurfactant exhibited satisfactory emulsification under all tested conditions, particularly at the highest temperature (100 \({}^{\circ}\)C), at which the emulsification index (E24) was always higher than 60% almost independent of the biosurfactant concentration and the type of oil. The only significant effect of the type of oil was detected with the CMC, where E24 was always higher for grape seed oil than for sweet almond oil. The emulsions remained stable when the solutions of the purified biosurfactants were exposed to different pH values, with a margin of stability near 45-50% (Figure 3). Consistent with the results obtained by varying the temperature, the E24 achieved the highest values (\(\geq\)50%) with the CMC. The results of the emulsions when submitted to variations in salinity (Figure 4) were promising in terms of stability, as E24 was always \(\geq\)45%. With only one exception at % CMC using 6% NaCl, at which E24 was the highest (\(\geq\)60%), no significant variation was observed in this parameter when varying either the concentration or the salinity level. Figure 1: Fourier transform infrared spectroscopy analysis of plant extracts containing the biosurfactants from _Glycine max_ (**A**) and _Chenopodium quinoa_ (**B**). Figure 2: Emulsification index of the biosurfactant from _Glycine max_ evaluated against two different oils (grape seed oil and sweet almond oil) at different temperatures (40 \(\leq\) T \(\leq\) 100 \({}^{\circ}\)C) and concentrations (% CMC (**A**), CMC (**B**), and 2 CMC (**C**)). Results are expressed as means \(\pm\) SD (\(n\) = 3), where means are significant at \(p<\) 0.05. Figure 3: Emulsification index of the biosurfactant from _Glycine max_ evaluated against two different oils (grape seed oil and sweet almond oil) at different pH values (2 \(\leq\) pH \(\leq\) 12) and concentrations (% CMC (**A**), CMC (**B**), and 2 CMC (**C**)). Results are expressed as means \(\pm\) SD (\(n\) = 3), where means are significant at \(p<0.05\). Figure 4: Emulsification index of the biosurfactant from _Glycine max_ evaluated against two different oils (grape seed oil and sweet almond oil) at different concentrations (% CMC (**A**), CMC (**B**), and 2 CMC (**C**)) and under different salinity conditions (\(2\leq\) NaCl \(\leq 12\%\)). Results are expressed as means \(\pm\) SD (\(n=3\)), where means are significant at \(p<0.05\). The results of the emulsification test using the biosurfactant from _C. quinaa_ demonstrated that this biomolecule was stable and tolerant to variations in temperature, with maintenance of stability \(\geq\)50% at all temperatures on both oils tested (Figure 5). Figure 5: Emulsification index of the biosurfactant from _Chenopodium quinao_ evaluated against two different oils (grape seed oil and sweet almond oil) at different temperatures (40 \(\leq\) T \(\leq\) 100 \({}^{\circ}\)C) and concentrations (% CMC (**A**), CMC (**B**), and 2 CMC (**C**)). Results are expressed as means \(\pm\) SD (\(n\) = 3), where means are significant at \(p\) < 0.05. The quinoa biosurfactant was stable at all pH values, with stability \(\geq\)50% in the oil-in-water emulsions, especially those composed of sweet almond oil, which was the system that achieved the best results as an average (Figure 6). Particularly, the highest E24 values (\(\geq\)60%) were obtained with the CMC and pH 10 with both oils, confirming this biosurfactant concentration as the most effective in terms of emulsification capacity.