Encapsulation of β-carotene within ferritin nanocages greatly increases its water-solubility and thermal stability

Carotenoids may play a number of potential health benefits for human. However, their use in food industry is limited mostly because of their poor water-solubility and low thermal stability. Ferritins are widely distributed in nature with a shell-like structure which offers a great opportunity to improve the water-solubility and thermal stability of the carotenoids by encapsulation. In this work, recombinant human H-chain ferritin (rHuHF) was prepared and used to encapsulate beta-carotene, a typical compound among carotenoids, by taking advantage of the reversible dissociation and reassembly characteristic of apoferritin in different pH environments. Results from high-performance liquid chromatography (HPLC), UV/Vis spectroscopy and transmission electron microscope (TEM) indicated that beta-carotene molecules were successfully encapsulated within protein cages with a beta-carotene/protein molar ratio of 12.4-1. Upon such encapsulation, these beta-carotene-containing apoferritin nanocomposites were water-soluble. Interestingly, the thermal stability of the beta-carotene encapsulated within apoferritin nanocages was markedly improved as compared to free beta-carotene. These new properties might be favourable to the utilisation of beta-carotene in food industry. (C) 2013 Elsevier Ltd. All rights reserved.