Recovery of Free Lutein From Tagetes erecta: Determination of Suitable Saponification and Crystallization Conditions

Abstract

This study deals with the separation and purification of lutein from marigold flowers. The effects of saponification conditions such as time (0–7 hr), volume to weight ratio of KOH solution to oleoresin (0.3 ml:1 g to 1 ml:1 g), and the concentration of KOH solution (25%–45% w/v) were first determined on the conversion of lutein fatty acid esters to free lutein. For 1 g of oleoresin, 0.5 ml of 40% v/v KOH solution was found to be the most suitable amount and concentration for the saponification of lutein esters to free lutein at 75°C. Following saponification, crystallization was carried out to determine the effect of crystallization solvents (water-ethanol and water-isopropanol mixtures), the composition of the crystallization solvents (2:0.3–2:1 v/v), and crystallization time (0.25–2 hr) on the yield and purity of free lutein. The results revealed that crystallization of the saponified sample in water-ethanol mixture at the volume ratio of 2:0.5 for 0.5 hr presented the highest yield of 99.12% of free lutein, at the purity of 85.53%.