Characteristic and storage stability of nanostructured lipid carriers containing red palm oil

Abstract

Red palm oil (RPO) is a potential carotenoid source mostly containing β-carotene. RPO instability requires a delivery system such as nanostructured lipid carriers (NLC). This research aimed to develop an NLC delivery system and study the characteristics of NLCRPO. The melting-emulsification-ultrasonication method was employed to produce the NLC-RPO based on 6% (w/w) lipids, with solid lipid to RPO ratio (SRR) varied 6:4, 7:3, and 8:2. Tween 80 (24% w/w) to lipids ratio of 4:1, and distilled water 70% (w/w). The solid lipids employed in this investigation were palm stearin (PS), and palm kernel stearin (PKS), while the liquid lipid was RPO. The stability of NLC-RPO was evaluated using βcarotene entrapment efficiency (EE), centrifugation, cooling, heating test, color, and pH for 90 days of storage. The NLC-RPO was characterized by particle size, polydispersity index (PDI), zeta potential, and viscosity before and after 90 days. Regression analysis was performed to evaluate the relationships between the storage and stability parameters. The highest encapsulation efficiency of β-carotene in NLC-RPO as a carrier β-carotene from the RPO was achieved when solid lipid to RPO ratio (SRR) of 6:4 and there was no significant difference in the type of solid lipid (PS and PKS) used. Generally, NLC-RPO stored for 90 days at room temperature showed good stability after centrifugation, cooling and heating tests with greenish-yellow color (-a*;+b*), and pH of 6.38-6.54. The particle size (38-87 nm), PDI (0.01-0.54), and zeta potential (-10.17 to -22.67 mV) did not significantly change over 90 days of storage, while the viscosity (8.36-9.11cP) was significantly different. The NLC-RPO with SRR of 6:4 had the highest β-carotene entrapment efficiency and remained stable after 90 days of storage at room temperature.