Effect of Chlorella Pulverization by Microfluidization on Lutein Micellization in Vitro and Uptake by Caco-2 Cells

Abstract

Chlorella is a nutrient-rich micoalga containing protein, lipid, minerals, vitamins, and high levels of lutein. In this study, the bioavailability of lutein from chlorella during chlorella digestion was evaluated by using the coupled in vitro digestion and human intestinal Caco-2 cell model. In simulated digestion of chlorella, the lutein micellization efficiency closely related to the lutein bioaccessibility was low, showing that about 70% of total lutein in chlorella was not micellized during digestion process but left in the insoluble digestate. Microfluidization was applied to improve the lutein micellization efficiency in the course of chlorella digestion. When the chlorella was microfluidized at the pressure of over 10,000 psi, the disruption of cell surface in chlorella was detected by scanning electron microscopy. The mean particle size of chlorella was able to reduce from 3.56 to 0.35 µm through the treatment of microfluidization. During the simulated digestion, the chlorella microfluidized at 20,000 psi was three times more efficient than untreated chlorella in the production of aqueous lutein micelles, and the final lutein contents accumulated by intestinal Caco-2 cells were also higher in the microfluidized chlorella. The stability of lutein in chlorella was not affected by the treatment of microfluidization. These results indicate that microfluidization may be a useful food processing for the improvement of lutein bioaccessibility from chlorella.