2.9 Determination of interfacial tension
A force tensiometer (K20 by Krüss GmbH, Hamburg, Germany) with a Wilhelmy plate (20 x 10 mm) was used to determine oil/water interfacial tension at room temperature. The oil phase (65 mL) with 4 wt% GMO was added in a wide-mouth glass beaker (130 mL). The Wilhelmy plate was immersed entirely in the oil phase, set as the zero-immersion depth. The plate was then removed and cleaned with acetone (A18-4, Fisher, US) and flamed with a butane torch (Bernzomatic, OH, USA). The aqueous phase (22 mL) was added to another similar glass beaker and placed over the stage. The plate was placed very close to the liquid-air interface for surface detection. Then, the oil phase was gently added to the aqueous solution with a pipette (VWR, Edmonton, AB, Canada) to fill the zero-immersion depth. The interfacial tension measurements were performed until a standard deviation of 0.1 mN/m could be reached between the readings.
2.10 Statistics
All emulsions were prepared in triplicate, and each of them was analyzed on day 0 and day 7, and the average and standard deviation were reported. The statistical analysis was performed using IBM SPSS Statistics 20, in which Tukey’s test was performed to compare the average with a significance level of 0.05.