Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/34047
標題: Continuous hot pressurized solvent extraction of 1,1-diphenyl-2-picrylhydrazyl free radical scavenging compounds from Taiwan yams (Dioscorea alata)
作者: Chen, P.Y.
張傑明
Tu, Y.X.
Wu, C.T.
Jong, T.T.
Chang, C.M.J.
鍾婷婷
關鍵字: Dioscorea alata
DPPH free radical
hot pressurized water
experimental
design
antioxidant activity
phenolic-compounds
subcritical water
plant-extracts
期刊/報告no:: Journal of Agricultural and Food Chemistry, Volume 52, Issue 7, Page(s) 1945-1949.
摘要: This study investigates a semicontinuous hot pressurized fluid extraction process and the scavenging activity on the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical of the extract from Taiwan yams (Dioscorea alata). Liquid-liquid extractions were preliminarily employed to generate six fractions, initially extracted by ethanol. Then, the aqueous solution of dried crude ethanol extract was sequentially fractionated by hexane, chloroform, ethyl acetate, and n-butanol. The EC50 value was defined as the UV absorption of DPPH concentrations sufficiently decreased to 50% of the original value. It was found that all peel portions have a better effect on scavenging of the DPPH free radical than meat portions, especially for the ethyl acetate partition of the peel portion of Tainung #2 yam. Its EC50 value (14.5 mug mL(-1)) was even lower than that of ascorbic acid (21.4 mug mL(-1)). Furthermore, semicontinuous hot pressurized ethanol was superior to hot pressurized water in extracting the compound scavenging the DPPH radical from the Purpurea-Roxb peel. The recovery of four unknown compounds corresponded to the scavenging ratio of DPPH free radical in the hot pressurized ethanol extract. Finally, three-level and four-factor experimental design revealed that ethanol ratio and temperature were the most effective factors in order. Conditions of 80% of aqueous ethanol, 20.0 kg/kg solid ratio, 180 psig (1.342 MPa), and 100degreesC were preferred to extract those antioxidants from the yam peel.
URI: http://hdl.handle.net/11455/34047
ISSN: 0021-8561
文章連結: http://dx.doi.org/10.1021/jf0351826
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