Karacabey Erkan, Mazza Giuseppe
Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, 4200 Highway 97, Summerland, British Columbia V0H 1Z0, Canada.
J Agric Food Chem. 2008 Aug 13;56(15):6318-25. doi: 10.1021/jf800687b. Epub 2008 Jul 16.
Optimization of the solid-liquid extraction conditions for trans-resveratrol, trans--viniferin, ferulic acid, and total phenolics from milled grape canes has been investigated. The temperature and ethanol concentration were found to be major process variables for all responses, whereas the solvent to solid ratio was found not to be significant for any of the responses studied. The yields of trans-resveratrol, trans--viniferin, and total phenolics increased with increasing temperature. Maximum yields of trans-resveratrol (4.25 mg/g dw), trans--viniferin (2.03 mg/g), and total phenolics (9.28 mg/g dw) were predicted from the combination of a moderate ethanol concentration (50-70%) and the highest temperature (83.6 degrees C), whereas an ethanol concentration of 35% at the lowest temperature studied (16.4 degrees C) was optimal for the extraction of ferulic acid (1.05 mg/g dw). Effective diffusivity values of resveratrol in the solid phase, D eff for different extraction conditions, were calculated by fitting the experimental results to a model derived from the Fick's second law. Effective diffusivity of resveratrol in the solid phase varied from 3.1 x 10 (-13) to 26.6 x 10 (-13) m (2) s (-1) with changing extraction conditions. The increase in effective diffusivity of resveratrol was observed with increasing temperature, and the highest predicted level was obtained when using 54% ethanol/water mixture at 83.6 degrees C. The increase in ethanol concentration exhibited the favorable effect up to 50-55%, thereafter effective diffusivity decreased with a further increase in concentration.
已对从碾碎的葡萄茎中提取反式白藜芦醇、反式葡萄素、阿魏酸和总酚类物质的固液萃取条件进行了优化研究。结果发现，温度和乙醇浓度是所有响应的主要工艺变量，而在所研究的任何响应中，固液比对其均无显著影响。反式白藜芦醇、反式葡萄素和总酚类物质的产率随温度升高而增加。通过中等乙醇浓度（50 - 70%）与最高温度（83.6℃）的组合，预测反式白藜芦醇（4.25毫克/克干重）、反式葡萄素（2.03毫克/克）和总酚类物质（9.28毫克/克干重）的产率最高，而在所研究的最低温度（16.4℃）下，35%的乙醇浓度最适合阿魏酸的提取（1.05毫克/克干重）。通过将实验结果与从菲克第二定律推导的模型进行拟合，计算了不同萃取条件下白藜芦醇在固相中有效扩散率的值，即Deff。随着萃取条件的变化，白藜芦醇在固相中有效扩散率在3.1×10（-13）至26.6×10（-13）平方米每秒之间变化。随着温度升高，观察到白藜芦醇有效扩散率增加，在83.6℃使用54%乙醇/水混合物时获得最高预测水平。乙醇浓度增加至50 - 55%时显示出有利影响，此后随着浓度进一步增加，有效扩散率下降。
