Preparation, characterization, stability and application of the H-type aggregates lutein/whey protein/chitosan...

Natural lutein is liposoluble and has powerful antioxidant activity, which can be self-aggregated to form H-type aggregates in organic-water systems. However，its application is limited by poor solubility and high instability. Here, whey proteins/chitosan-coated H-type aggregates lutein nanoparticles (NPs) were fabricated via a bottom-up layer-by-layer self-assembly technique. The optimal conditions for the preparation of the NPs (173.3 nm) were determined by the Dynamic Light Scattering and UV-vis spectroscopy. Briefly, three proteins (WPI and WPC and BSA) were used to fabricate polysaccharide-protein nanocarriers to encapsulate the lutein. These spectroscopy studies indicated that chitosan and BSA formed hydrophobic microdomain by the intermolecular electrostatic attraction force with remarkable changes of secondary structure in protein. The morphology revealed that the NPs were nearly spherical. The EE of the NPs was ≥90.4 %, with a LC of up to 28.3 %. Lutein in NPs can be stabilized as H-type aggregates at different temperatures and pH-values. Additionally, the cytotoxicity test of the NPs on L929 and Caco-2 cells showed that NPs had low cytotoxicity in a limited concentration range. Results indicated that whey protein/chitosan-coated lutein nanoparticles significantly improved water dispersion and stability of lutein and its aggregates, thus broadening their application in nutrient delivery system.