Thesis (M.Sc.) - Cairo University -Faculty of Agriculture - Department of Food Science and Technology

The effect of extraction time, ultrasound intensity, plant material/solvent ratio and extraction technique on the extraction yield of total carotenoids from Delonix regia flowers were investigated. Spectrophotometer was used to determine the total carotenoids.Combination of ultrasound and magnetic stirring extraction techniques (US+S) was compared with the conventional stirring (S) alone. Ultrasound assisted extraction proved to be as a promising technology for extracting carotenoids from Delonix regia flowers at relatively short extraction times compared with the conventional method. The optimal conditions for obtaining the highest yield of carotenoids from Delonix regia petals were: 1:20 (w/v) material/solvent ratio,10% ultrasonic intensity of the maximal power (300 W) for 50min. At these conditions, the yield of total carotenoids was 503.0 æg/g dry weight. Increasing acoustic power density degraded carotenoids. HPLC analysis was used for the quantification of Ý-carotene in the extract. The carotenoid-rich extract that was obtained by using US+S was evaluated in terms of its DPPH (1,1-diphenyl-2-2-picrylhydrazyl) radical scavenging activity and FRAP (Ferric reducing antioxidant power)

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