Preparation, characterization, and physical stability of cocoa butter and tristearin nanoparticles containing β-carotene

Abstract

Solid lipid nanoparticles (SLN) have emerged as a potential delivery system for bioactive ingredients, as they are associated with improving the stability of incorporated bioactive components by preventing their diffusion to the particle surface. The aim of this study was to investigate the impact of carrier lipid composition and surfactant type on the physical stability and thermal behavior of SLN containing β-carotene. As carrier lipids we used cocoa butter and/or tristearin and as surfactants we used Quillaja saponin extract in a combination with high- or low-melting lecithin. All the ingredients were food-grade. The results showed that all the SLN were physically stable and had a particle diameter < 200 nm, except for SLN containing only tristearin as carrier lipid and Quillaja saponins and low-melting lecithin as emulsifier, which showed slightly increased particle sizes during storage due to polymorphic transition. In general, this study indicated that the introduction of heterogenous lipids can improve the physical stability of the SLN due to the more random crystal structures formed. Moreover, the polymorphic stability is dependent on the surfactants applied. These results are of interest for manufacturers in food, pharmaceutical, cosmetic and personal care industries using cocoa butter or any lipid blend to enrich their products with bioactive components.