Physicochemical stability and in vitro evaluation of solid lipid microparticles with palm kernel oil

Author(s)

Janaina Costa da Silva

• Document type: Master's Dissertation
• Press: Pirassununga.
• Institution: Universidade de São Paulo (USP). Faculdade de Zootecnica e Engenharia de Alimentos (FZE/BT)
• Defense date: 2013-03-28

Examining board members

Samantha Cristina de Pinho; Rosemary Aparecida de Carvalho; Rosiane Lopes da Cunha

• Advisor: Samantha Cristina de Pinho

Abstract

The present study proposed the production of solid lipid microparticles using stearic acid / tristearin and palm kernel oil, and the evaluation of their physical and chemical stability and in vitro digestibility. In the dispersions containing stearic acid and palm kernel oil the surfactants used were polysorbate 20 and span 80 (4% wt). In the production of dispersions containing tristearin and palm kernel oil, polysorbate 60 and span 80 (4% wt) were used as surfactants, as well as xanthan gum (0,05% wt) as thickener. The percentage of palm kernel oil ranged between 30 and 90% of the overall lipid content of the particles. With respect to microstructure, all the microparticles produced had completely amorphous characteristic, a desired characteristic for the encapsulation of a hydrophobic bioactive, as in amorphous particles the chance of expulsion is decreased. With regard to shelf life, all microparticles were extremely stable during the considered storage period, and the particle size distributions were always bimodal, with a population of particles around 300 nm and the other at approximately 1500 nm. Analyses of zeta potential and polydispersity over time storage confirmed the high stability of the systems produced. When submitted to different stress conditions, the microparticles produced with stearic acid and palm kernel oil were less stable than those produced with tristearin. As for digestibility assays, static experiments showed much worse results than the in vitro dynamic assays. The analyses of average size distribution, zeta potential, quantification of free fatty acids and optical microscopy showed inhibition of lipolysis during the digestibility assays, which was more pronounced in the microparticles produced with stearic acid. However, it is possible to say that the lipid microparticles produced in this work can be structured to produce effective controlled release of bioactive encapsulated. (AU)

• FAPESP's process: 10/13229-8 - Microstructure, stability and in vitro digestibility of solid lipid microparticles containing medium chain triacylglycerides
• Grantee: Janaína Costa da Silva
• Support Opportunities: Scholarships in Brazil - Master