Browsing by Author "Silva, Gabriela Gomes da"
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- Liposome systems for passion fruit seed oil encapsulation in view of cosmetic applicationsPublication . Silva, Gabriela Gomes da; Barreiro, M.F.; Fernandes, Isabel P.; Sipoli, Caroline CasagrandeThe generation of waste is one of the greatest and most damaging environmental risks. In the passion fruit juice industry, where only pulp is used, seed residues represent 12% of the fruit. They contain a high oil content (28 to 30%) rich in unsaturated fatty acids, tocopherols, carotenoids, and phenolic compounds, being also reported as presenting antioxidant activity and health benefits. Liposomes are spherical vesicles formed by phospholipids that, due to their amphoteric nature, when placed in aqueous solution self-aggregate, exposing the hydrophilic part and hiding the hydrophobic part, thus being able to encapsulate substances. In this context, the application of the oil extracted from the passion fruit seed (obtained from UTFPR), its characterization and encapsulation in liposomes for cosmetic applications was studied. The oil was characterized in terms of fatty acid profile, antioxidant activity, and oxidative stability. The fatty acid profile showed a predominance of unsaturated fatty acids, especially linoleic and oleic acids. The antioxidant activity was measured through the reducing activity related to the presence of phenolic compounds and through the capture of DPPH free radicals, being verified an intermediate antioxidant activity. The study of the oxidative stability proved the low stability of the oil, justifying its encapsulation before application, to preserve properties. To prepare the liposomes, the phosphatidylcholine was used as the lipid and the ethanol injection method (scalable) selected as the productive process. The method consists of preparing an aqueous phase and an organic phase containing the active ingredient to be encapsulated. Then, the organic phase is pumped into the aqueous phase under controlled flow, temperature, and stirring. After the production of the vesicles, the final step corresponds to the evaporation of the solvent in a rotary evaporator. The influence of parameters such as stirring and solvent evaporation times, on the vesicle final sizes was studied, being verified that the increase in stirring and evaporation time favor the agglomeration of liposomes. Liposomes were characterized in terms of size, morphology, stability and encapsulation efficiency. Through optical microscopy (OM) it was verified the spherical morphology of the liposomes and the influence of the solvent in their behaviour. Encapsulation efficiency tests for different oil concentrations were done indicating that the one comprising 20% w/w of oil was the higher one. The zeta potential was measured (-28.23 mV), showing the low stability of the vesicles that were further subjected to coating with chitosan. Two methodologies for particle’s drying were studied: lyophilization, with the use of a cryo-protector (maltodextrin), and spray-drying after chitosan coating. Dry liposomes were characterized in what concerns size, morphology and stability. Optical and scanning electron microscopy proved the sphericity of the vesicles. The laser diffraction technique allowed measuring the size of the particles, showing that the size increased after drying due, which was associated to particle agglomeration. Visual analyses allowed to check stability, being verified that lyophilized liposomes released part of the encapsulated oil after 2 months of storage, being spray-drying after chitosan coating the most suitable methodology to produce liposomes in the dry form.