| Summary: | 碩士 === 輔仁大學 === 食品營養學系 === 93 === Lycopene, one of the major carotenoids that are widely present in vegetables and fruits. Many reports have shown that lycopene may reduce the risk of prostate gland cancer or other cancers. The cis isomers of lycopene can be absorbed more readily than its all-trans form and thus has been reported to possess higher biological activity. Because of presence of long-chain conjugated double bonds, lycopene is susceptible to oxidative degradation and isomerization during heating or illumination. Oxidative degradation can decrease biological activity while isomerization can enhance biological activity. Therefore, it is necessary to develop a powder product which contains high amount of cis-lycopene. The objectives of this study were to compare the extraction efficiency and degree of isomerization of lycopene by employing supercritical carbon dioxide and solvents, as well as analyze the contents and varieties of cis-isomers of lycopene as affected by different drying methods, so that a powder product containing high level of cis-lycopene can be obtained. Results showed that the highest yield of lycopene can be achieved by supercritical carbon dioxide extraction at 350 bar and 70℃, with cis isomers making up 41.4% of total lycopene, and the total amount of lycopene was 650.0μg/g. However, with temperature at 80℃and 90℃, the maximum isomerization was accomplished, with cis isomers making up 51.0% and 53.8％ of total lycopene, respectively, while the total amounts of lycopene were 587.9 μg/g and 579.9 μg/g.
For solvent extraction, the highest yield of all-trans-lycopene was attained by ethanol-hexane(4/3, v/v) at 25℃ and 50℃. The amount of cis-lycopene increased with increasing temperature, and the maximum formation of cis isomers (47.0% of total lycopene) was observed at 75℃. However, the total amount of lycopene was 496.6 μg/g. A powder product containing 1028 μg/g lycopene was obtained by spray-drying, of which cis isomers constituted 34.5% of total lycopne. With freeze-drying, a powder product containing 42.1 μg/g lycopene was obtained. Also, freeze-drying did not generate a higher yield of lycopene(all-trans plus cis form) than spray-drying. The lycopene powder was also processed by adding sodium alginate to the eluate after open-column chromatography, which contained 34366.1 μg/g of all-trans-lycopene, 24244.4 μg/g of cis-lycopene, and a total of 58610.5 μg/g lycopene, with cis isomers making up 41.4% of total lycopene.
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