Quantitative Determination of Allicin in Garlic: Supercritical Fluid Extraction and Standard Addition of Alliin
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- 作者：Michael E. Rybak ; Elizabeth M. Calvey ; and James M. Harnly
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2004
- 出版时间：February 25, 2004
- 年：2004
- 卷：52
- 期：4
- 页码：682 - 687
- 全文大小：84K
- 年卷期：v.52,no.4(February 25, 2004)
- ISSN：1520-5118
文摘
A quantitative method is described for the determination of allicin (2-propene-1-sulfinothioic acid S-2-propenyl ester) in garlic, using standard additions of alliin (L-(+)-S-allylcysteine sulfoxide) in conjunctionwith supercritical fluid extraction (SFE) and high performance liquid chromatography analysis withUV-vis absorbance detection. Optimum CO2-SFE conditions provided 96% recovery for allicin withprecision of 3% (RSD) for repeat samples. The incorporation of an internal standard (allyl phenylsulfone) in the SFE step resulted in a modest improvement in recovery (99%) and precision (2%RSD). Standard additions of alliin were converted to allicin in situ by endogenous alliinase (L-(+)-S-alk(en)ylcysteine sulfoxide lyase, EC 4.4.1.4). Complete conversion of the spiked alliin to allicinwas achieved by making additions after homogenization-induced conversion of the naturally occurringcysteine sulfoxides to thiosulfinates had taken place, thus eliminating the likelihood of competingreactions. Concentration values for allicin determined in samples of fresh garlic (Allium sativum L.and Allium ampeloprasum) and commercially available garlic powders (Allium sativum L.) by standardaddition of alliin were found in all cases to be in statistical agreement (95% confidence interval) withvalues determined using a secondary allicin standard (concentration determined using publishedextinction coefficients). This method provides a convenient alternative for assessing the amount ofallicin present in fresh and powdered garlic, as alliin is a far more stable and commercially prevalentcompound than allicin and is thus more amenable for use as a standard for routine analysis.Keywords: Alliin; allicin; alliinase; cysteine sulfoxides; thiosulfinates; standard addition; supercriticalfluid extraction; high performance liquid chromatography