Nanostructured Lipid Carriers in Alginate Microgels for the Delivery of Astaxanthin

Abstract

This study aims to enhance the stability and bioavailability of astaxanthin by loading it into nanostructured lipid carriers (NLCs), then incorporating the NLCs into alginate microgels. The NLCs (about 200 nm particle size) and alginate microgels (about 1 mm particle size) are prepared using high‐pressure homogenization and injection‐gelation methods, respectively. Based on in vitro dissolution assessments, the astaxanthin in alginate microgels dissolves more slowly than that in NLCs. In simulated gastric digestive juice, minimal dissolution of microgel‐embedded astaxanthin is detected; however, in simulated intestinal digestive juice, the dissolution is appreciably accelerated. Moreover, the 2 h bio‐accessibility of astaxanthin in microgels is less than that in NLCs. At higher concentrations of sodium alginate and calcium ions, the internal pores of the microgels become smaller, resulting in slower dissolution and lower bio‐accessibility of astaxanthin. As for the chemical stability of the pigment, it is improved by the secondary coating effect of hydrogelation. Hence, NLC incorporation into alginate microgels constitutes a promising strategy for the encapsulation of astaxanthin in the food industry. Practical applications : Nanostructured lipid carriers (NLCs) incorporated in alginate microgels can increase the water solubility of astaxanthin, improve its chemical stability, increase its bioavailability, and allow for its controlled release. The high‐pressure homogenization method used to prepare NLCs can be easily applied on an industrial level. Moreover, the operation conditions of the injection‐gelation process needed to synthesize the alginate microgels are mild, nontoxic, and nonpolluting. The NLC‐alginate microgels can be used in yogurt, ice cream, and other foods.

Preparation of astaxanthin/zeaxanthin-loaded nanostructured lipid carriers for enhanced bioavailability: Characterization-, stability-and permeability study

“…Available studies on ASTA and ZEA incorporated into NLCs are scarce but promising. In the present case, the ASTA-NLC exhibited higher effective diameter compared to those reported by Tamjidi and coworkers (29) and Rodriguez-Ruiz and coworkers (30) (which were 94 nm and 60 nm, respectively), and similar to the one reported by Huang and coworkers (31) which was around 200 nm. According to our knowledge, there is just one group that recently incorporated ZEA into NLCs and obtained ZEA-NLC characterized with a smaller average effective diameter which did not exceed 130 nm (32).…”

“…The EE is considered the major factor to be considered when assessing the applicability of NLCs as carriers of bioactive molecules. The EE of ASTA-NLC was 58.0 ± 6.9 %, which is similar to the value reported by Huang and coworkers (31) and lower than reported previously by Tamjidi and coworkers (29) and Rodriguez-Ruiz and coworkers (30). On the other hand, the EE of ZEA-NLC was significantly higher compared to the ASTA-NLC.…”

“…The polydispersity of ASTA-NLC increased from 0.128 in water to 0.262 in FaSSIF while for ZEA-NLC increased from 0.122 in water to 0.264 in FaSSIF indicating less uniformed size distribution of particles under GI conditions. Similar phenomena were also reported and explained by the impact of anionic components such as free fatty acids, phospholipids, and bile salts present in the reaction mixture (31,40).…”

Preparation of microgel co-loaded with nuciferine and epigallocatechin-3-gallate for the regulation of lipid metabolism

“…Microgels (d. 1∼350 μm) are swellable polymer networks with hydrophilic functionalities that allow them to entrap large amounts of water without collapse and are usually prepared by polymer (polysaccharides and/or proteins) cross-linking through ionic, physical, or covalent interactions ( 9 ). Microgels have been widely used in the encapsulation of various unstable substances, such as astaxanthin ( 10 ) and polyphenols ( 11 ), to improve their stability and bioavailability and control their release. Myrica rubra leaf proanthocyanidin extract (MLPE) and chitosan are abundant natural materials widely used in the food industry because of their safety and good functional properties.…”