Effect of Chlorophylls on the Bioaccessibility of Lutein

Lutein has a variety of physiological activities, which can not be synthesized by human body and can only be obtained through diet. Dietary lutein shows low bioaccessibility due to its lipo-soluble nature and thus the efficient supplementation of lutein has become a research hotspot. Chlorophylls, another type of lipo-soluble phytochemicals, are always ingested along with lutein in human diet where interaction between chlorophylls and lutein may occur. Therefore, it is of great significance to study the effect of dietary chlorophylls compounds and their structural changes on the bioaccessibility of lutein. Based on this, in this paper, eight different structures of chlorophylls (chlorophyll a, chlorophyll b, pheophytin a, pheophytin b, chlorophyllide a, chlorophyllide b, pheophorbide a and pheophorbide b) were prepared, and their effects on lutein bioaccessibility and related indexes were studied by in vitro static digestion model and micellization investigations. Changes of particle size and zeta-potential of mixed micelles formed by lutein and chlorophylls were also determined. The results showed that all the chlorophylls structures significantly improved the recovery rate and bioaccessibility (P<0.05) from in vitro digestion of lutein. Among them, pheophytin b exerted the most significant influence, with the corresponding recovery rate and bioaccessibility index of lutein being 90.48% and 80.44%, respectively. During digestion, no significant lutein degradation products were detected, while the structures of chlorophylls underwent significant changes. It could be found that the micellar fraction was more stable than the digesta fraction by the comparison of average particle size, fluorescence images and zeta potential value. Chlorophylls could protect lutein from degradation during in vitro digestion by forming some complex. This study provided important information on how to improve the bioaccessibility and digestion and utilization performance of dietary lutein.