Delivery of natural Monascus yellow pigment using zein-lecithin nanoparticles: Fabrication, characterization, and in vitro release properties

Monascus yellow pigment (MYP) is an important secondary metabolite of polyketone produced by Monascus sp. MYP is not only a great food colorant but also possesses beneficial active functions for human body. However, its application is currently limited due to the pH instability and low bioavailability. This can be solved by loading MYP in zein-lecithin nanoparticles. The structure and encapsulation efficiency of nanoparticles varied due to the different proportions of zein-lecithin-MYP components. When the mass ratio was 4:4:1, the encapsulation efficiency was 60.82% and loading capacity was 12.61%, respectively. Scanning electron microscope observation showed that zein-lecithin-MYP nanoparticles (MYP@Z-L NPs) were globular and uniformly distributed with increasing of lecithin content. The results of Fourier infrared spectroscopy confirmed that MYP was successfully embedded in the nanoparticles, primarily through hydrogen bonding, electrostatic and hydrophobic interactions. Stability study of MYP@Z-L NPs showed that it had better resistance to low pH than free MYP and could be stored for up to 4 weeks. Therefore, the zein-lecithin composite nanoparticles with a mass ratio of 4:1 can be an effective carrier for the active protection and long-term utilization of MYP and have a great application potential in the food industry.