Technological insights into lutein isolation from marigold flower and their diverse applications: a compendious review

In our comprehensive review, we delve into the critical steps of isolation of lutein and zeaxanthin from marigold flowers focusing on several pre-treatment technologies for marigold flower hydrolysis, non-green and green solvent-based extraction techniques of hydrolyzed solid biomass, and saponification of oleoresin while addressing the associated challenges and limitations. The review highlights the varying effects of different pre-treatments on the degradation of pectin, lignin, cellulose, and hemicellulose as well as on lutein and zeaxanthin ester yield. Notably, the enzymatic pre-treatment emerges as the most efficacious approach, despite its reliance on costly commercial enzymes. Based on the literature review, it is determined that supercritical fluid extraction, combined with ultrasound and various co-solvents gives off better yields of lutein as compared to the other extraction methods. This review also covers the saponification, purification, and recovery process. The applications of marigold flowers and lutein are also summarized.