The present study aimed to evaluate the surface properties of the plasma and hemoglobin in different values of pH and concentrations. The two samples showed similar profiles foaming capacity in the pH range tested (3, 5, 7, 8 and 11) but with different values and distant from neutrality. The plasma showed the lower foaming capacity and foam stability for all pH values. The values of emulsion stability were higher to the plasma in all pH, and all showed values are equal statistically. Observed for the plasma, the higher foaming capacity was for concentration of 0.50%, higher and statistically different from the others concentrations. Decrease in the concentration of sample to 0.1% and 0.25%, led to a reduction in foam stability using plasma and hemoglobin. For the two samples, from the concentration of 1.5%, the values of emulsifying activity were similar. Statistically, the values obtained at concentrations of 1.5% and 2.5% were statistically equal to each other and different from the values obtained for 3.5 and 4.5%. The emulsion formed using plasma and hemoglobin was more stable from the concentration of 3.5% and 1.5 %, respectively. Regarding the surface properties, the proteins were shown to be promising for use in food.

Geraniol has been an attractive compound for food preservation due to its antibacterial and antifungal actions. The main objective of this study was to produce and characterize polycaprolactone (PCL) capsules for the protection of the encapsulated geraniol essential oil. The encapsulation was carried out using a miniemulsion polymerization technique with an efficiency of (95.44 ± 0.60%). The capsules were obtained with a mean size of 148 nm and with a polydispersity index of 0.12. Transmission electron microscopy results confirmed the formation of spherical capsules of PCL coating the geraniol. From the analysis of thermogravimetry, it was possible to prove the thermal protection of geraniol by PCL coating since the release of the encapsulated geraniol occurred with temperatures 100 °C higher than the volatilization temperature of the natural compound. An important observation was that the microcapsules of PCL-geraniol immersed in aqueous suspensions at 4 °C showed good stability over 60 days.

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Miniemulsion polymerization process is a very versatile technique used for the polymeric encapsulation of the many essential oils. In this process some surfactant compounds are used to define the capsules characteristics, as an example the Sodium Lauryl Sulphate (SLS) that is one of the most used surfactants. But, after the miniemulsion polymerization synthesis the residual amount of SLS can manifest an antimicrobial action that can improve or to prejudice the final properties of the encapsulated products, depending of its percentual concentrations. In this sense, the objective of this work was to evaluate the antimicrobial activity of polycaprolactone (PCL) capsules synthesized with different residual concentrations of the SLS surfactant after the miniemulsion polymerization processes. The antimicrobial evaluations demonstrated from solid media diffusion test that the PCL microcapsules are microbiologically inactive for the bacteria Staphylococcus aureus and Escherichia coli when are synthetized with residual concentrations of SLS below 0.0125%. The minimum inhibitory concentration (MIC) of residual SLS for the bacteria Staphylococcus aureus is 0.0146% and for the bacteria Escherichia coli the complete bacterial inhibition not was detected at the maximum residual concentration studied of 0.1167%.

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