Underlying laws governing the saponification and crystallization separation of free lutein from marigold oleoresin

Abstract

There is an increasing demand for natural lutein compared to artificial ones, driven by a preference for natural and healthy lifestyles. However, the unclear potential processes for producing free lutein limit its production and impede further industrial development. This paper systematically investigates the saponification and crystallization processes for separating free lutein from marigold oleoresin, including the kinetics of the saponification process, changes in free lutein, fatty acid, and carotenoid content during saponification, as well as the characterization of the resulting crystals. The results demonstrate that the hydrolysis of lutein esters follows a second-order reaction. Additionally, the presence of impurities in marigold oleoresin enhances lutein production. The saponification of fatty acid esters occurs prior to that of lutein esters, resulting in the formation of larger hexagonal crystals from marigold oleoresin. Under optimal conditions, a lutein purity of 90.20 % was achieved. This study provides theoretical guidance for lutein production from marigold oleoresin.