Extraction And Characterization Of Carotenoids From Marigold Flower

Lutein is the major carotenoids in marigold flower (Tagetes erecta L.).It is found recently that lutein had multiple bio-functions such as enhancing immune function, antioxidant, free radical scavenging, and antitumor activities. Lutein can also decrease the risk of cataract, age-related macular degeneration (AMD), and cardiovascular disease. In this work, systematic studies were carried out on the isolation, purification, quantification, antioxidant activity, free radical scavenging activity of lutein from marigold flower {Tagetes erecta L.).The optimum conditions of purification by thin-layer chromatography (TLC) was obtained using silica G plate as the support and a solvent mixture of petroleum ether/acetone as the evolving solvent. Lutein was qualitatively identified by various physico-chemical properties such as Rf value from TLC, the color change on reaction with Ag⁺,UV-visible absorption spectra, the retention time and the molecular weight as measured by LC-MS. The apart component was identified as lutein.The technology of lutein preparation was obtained from marigold flower followed by acetone extraction and TLC or column chromatography. Firstly, three significant factors (temperature, feed:solvent ratio and time) on total carotenoid and lutein yield were obtained using one-at-a-time design (p<0.05). Subsequently, the parameters of lutein extraction was optimized (F>F_0.01).The reacting equation wasThe optimal extraction conditions were 48℃,1:118 and 117min. Under these conditions, the yield of carotenoids was 13.6289mg/g.Supercritical CO₂ fluid extraction is a kind of new extracting technology. Supercritical carbon dioxide extraction was used for the extraction of carotenoids from the marigold flower {Tagetes erecta L.) using statistical analysis. Firstly, five significant factors (particle size, temperature, pressure, time and co-solvent addition) on total carotenoid and lutein yield were obtained using one-at-a-time design (p≤0.05).Subsequently, in order to study the mutual interactions between variables, the effects of these factors were further investigated using three-factor, three-level orthogonal test design (F>F_0.01).The reacting equation wasThe optimal extraction conditions were 62C,48 MPa and 178 min. Under these conditions, the yield of carotenoids was 6.9775mg/g. The antioxidant property was investigated by ferric thiocyanate method (FTC). Lutein exhibited high antioxidant activities in the linoleic acid auto-oxidation process. The extract and its fractions showed antioxidant and antiradical properties as revealed following study using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. The DPPH radical-scavenging activity of carotenoids was significantly higher (p<0.05) than that of vitamin C, a commercial antioxidant used in the food industry. The results could guide in the formulation and development of functional food products that have high antioxidant potential.Finally, the various factors that influence the stability of the carotenoids extracted from marigold were studied and the results indicated: Light has great effect on carotenoids compound, it can destroy the pigment, the retention rate is 11.98% after placed in sunlight for 48h, but there is little effect to the ones placed in dark; As the temperature increased and the time prolonged, the carotenoid retention rate was reduced; Salt, maltose, sucrose and glucose have little effect on the stability of the carotenoids; Carotenoids are stable in the evbironment of Na⁺,Zn²⁺,K⁺,Mg²⁺ and Fe²⁺,Fe³⁺,Cu²⁺,AI³⁺ can destroy the compound greatly and they will accelerate the decomposition of carotenoids.