Stability assessment of lutein under the existence of different phenolic acids

The instability of lutein limited its application in the food industry. The study investigated the effects of ten phenolic acids (tannic acid, gallic acid, ferulic acid, syringic acid, rosmarinic acid, 3, 4-dihydroxybenzoic acid, caffeic acid, vanillic acid, coumalic acid, and chlorogenic acid) on the physical and chemical stability of lutein under dark/light and different temperatures. Moreover, the lutein stability with phenolic acids in food models was further assessed in different food processing methods and subsequent biscuit storage. The addition of rosmarinic acid, gallic acid, caffeic acid, and tannic acid significantly improved lutein stability during different conditions. Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) analyses indicated that lutein could interact with selected phenolic acids (rosmarinic acid, gallic acid, caffeic acid, and tannic acid) through hydrogen bonds and van der Waals forces. Additionally, the lutein under the existence of selected phenolic acids presented strong thermal stability in different food processing methods. Compared with the storage for 9 days at 27 °C, these phenolic acids also exhibited significant protective effects on lutein in biscuits after the storage for 3 days.