Influence of lipid content and dilution on properties and stability of nanostructured lipid carriers (NLCs) prepared from rambutan (Nephelium lappaceum L.) kernel fat and evaluation of their β-carotene loading capacity

Abstract

The effects of lipid content and dilution on the properties and stability of nanostructured lipid carriers (NLCs) prepared from rambutan (Nephelium lappaceum L.) kernel fat were investigated. The β-carotene-loading capacity of the NLCs was also evaluated. NLCs containing various lipid phase concentrations (5, 10, and 15 wt%) were prepared using Tween 80 as the emulsifier with a lipid to emulsifier weight ratio of 1:0.2. The results showed that an increase in the lipid content up to 15 wt% had no effect on the zeta-potential, particle size and polydispersity index but resulted in a higher particle density. All samples showed no phase separation during storage at 25 °C for 28 days; however, the relative recrystallization index (RRI) increased. Dilution of concentrated NLC (15 wt%) to a lower lipid content (5 and 10 wt%) produced no differences in the particle characteristics and stability during storage. NLCs loaded with β-carotene at different concentrations (0, 0.5, and 1 wt% of the lipid phase) exhibited desirable characteristics and had high encapsulation efficiency (∼97%) over 28 days of storage. These results demonstrated that NLC prepared from rambutan kernel fat can be used to entrap lipophilic bioactive components which could be used as ingredients in functional food products.

Graphical Abstract

Keywords:

• nanostructured lipid carrier
• rambutan kernel fat
• lipid content
• dilution effect
• β-carotene loading capacity

Acknowledgments

This work was supported in part by a Graduate Program Scholarship from the Graduate School, Kasetsart University. We would like to thank Assoc. Prof. Dr. Parichat Hongsprabhas for her useful suggestions and Malee Sampran Public Company Limited (Nakorn Pathom, Thailand) for providing the rambutan seeds used in this work.