Avaliação de surfactantes de grau alimentício na formação de microemulsões W/O para posterior encapsulação de betalaina por coacervação complexa
Data
2017-03-13
Autores
Higuita, Diana Maria Cano [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
As microemulsões (MEs) são misturas isotrópicas e termodinamicamente estáveis de dois solventes imiscíveis estabilizados por surfactantes, com múltiplas aplicações em indústrias químicas, farmacêuticas e alimentares. O objetivo deste trabalho foi a avaliação de dois surfactantes de grau alimentar - monooleato de sorbitano (Span 80) e polissorbato 80 (Tween 80) - na formação de MEs com adição de propilenoglicol como co-tensioativo e a caracterização do sistema resultante. O estudo priorizou a fase isotrópica formada por MEs, cujas propriedades foram investigadas por condutividade elétrica, reologia, calorimetria de varredura diferencial e calor específico. Sete sistemas detectados foram identificados como MEs ao longo do surfactante para proporções de óleo 9: 1 e 8: 2 linhas de diluição, até 20% de água. Os sistemas obtidos mostraram uma condutividade baixa, comportamento newtoniano típico de sistemas microemulsionados e, por meio de análises qualitativas foram identificadas como sistemas óleo em água (O/W). As análises de SAXS serviram para determinar o tamanho o qual está numa faixa que varia entre ≈70 Å e ≈90 Å, com forma definida como globular achatada e/ou em forma de core-shell. Foram incorporados diferentes conteúdos de extrato de betalaina na fase aquosa da microemulsão, que se mostrou estável e foi utilizada para produzir microcápsulas liofilizadas. A distribuição de tamanho de partícula, morfologia, retenção de betalaina e parâmetros de cor foram medidos, além de um teste de estabilidade de armazenamento para avaliar a degradação do corante em condições controladas de temperatura e umidade relativa. Após 48 dias, observou-se uma retenção de betalaina de 62%, com ligeiras alterações de cor.
The microemulsions (MEs) are isotropic and thermodynamically stable mixtures between two immiscible solvents stabilized by surfactants with multiple applications in chemical, pharmaceutical and food industries. This work aims to evaluate two food grade surfactants – sorbitan monooleate (Span 80) and polysorbate 80 (Tween 80) – on formation of MEs, with addition of propylene glycol as cosurfactant and posterior characterization of the resulting system. The study prioritized the isotropic phase formed in the MEs, since their properties investigated by electric conductivity, differential scanning calorimetric and specific heat. Seven systems were obtained and identified as MEs along the dilution lines from surfactant:oil ratios of 9:1 and 8:2, up 20% of water. The systems obtained showed low conductivity, Newtonian behavior of typical microemulsion and, system oil in water (O/W) from a qualitative analysis. Analyses of SAXS shows a size ranging from ≈70 Å to ≈90 Å, with a shape defined as flattened globular and/or core-shell form. Once obtained and characterized the MEs, different contents of betalaine extract were incorporated into the aqueous phase of the microemulsion until the stabilization and mixture with wall materials to produce microcapsules by lyophilized process. Particle size distribution, morphology, betalain retention and color analyses were determined in the betalain microcapsules. In addition, a storage stability test to evaluate the degradation of the dye under controlled conditions of temperature and relative humidity, observing after 48 days, retention values of 62% with slight color changes.
The microemulsions (MEs) are isotropic and thermodynamically stable mixtures between two immiscible solvents stabilized by surfactants with multiple applications in chemical, pharmaceutical and food industries. This work aims to evaluate two food grade surfactants – sorbitan monooleate (Span 80) and polysorbate 80 (Tween 80) – on formation of MEs, with addition of propylene glycol as cosurfactant and posterior characterization of the resulting system. The study prioritized the isotropic phase formed in the MEs, since their properties investigated by electric conductivity, differential scanning calorimetric and specific heat. Seven systems were obtained and identified as MEs along the dilution lines from surfactant:oil ratios of 9:1 and 8:2, up 20% of water. The systems obtained showed low conductivity, Newtonian behavior of typical microemulsion and, system oil in water (O/W) from a qualitative analysis. Analyses of SAXS shows a size ranging from ≈70 Å to ≈90 Å, with a shape defined as flattened globular and/or core-shell form. Once obtained and characterized the MEs, different contents of betalaine extract were incorporated into the aqueous phase of the microemulsion until the stabilization and mixture with wall materials to produce microcapsules by lyophilized process. Particle size distribution, morphology, betalain retention and color analyses were determined in the betalain microcapsules. In addition, a storage stability test to evaluate the degradation of the dye under controlled conditions of temperature and relative humidity, observing after 48 days, retention values of 62% with slight color changes.
Descrição
Palavras-chave
Microemulsão, SAXS, Microemulsion, Condutividade elétrica, Distribuição de tamanho de partícula, Electric conductivity