葡萄酒缩合单宁测定方法的比较研究

Comparison of Two Methods for the Determination of Condensed Tannins in Wine

目的:对比葡萄酒中测定缩合单宁的甲基纤维素沉淀法(MCP法)和蛋白质沉淀法(A-H法),以寻找一种快速准确的测定方法。方法:采用两种方法测定不同类型、产地、品种葡萄酒的缩合单宁,考察其测定值和变异系数;采用液相色谱-质谱联用法(HPLC-MS法)测定缩合单宁含量,采用吸光度法(A280)测定总酚含量,并与上述两种方法的结果对照。结果:(1)MCP法和A-H法均只适用于红葡萄酒缩合单宁测定,MCP法精度略高但差异不显著。(2)MCP法测定值平均为A-H法的9.13倍,但二者存在较好的线性关系(R2=0.6029)。MCP法与HPLC-MS法线性关系良好(R2=0.7733),A-H法较差(R2=0.4843)。(3)MCP法与总酚存在良好的线性关系(R2=0.9095),A-H法与总酚无显著线性关系(R2=0.2872)。结论:两种方法均能反映红葡萄酒缩合单宁含量,但MCP法与HPLC-MS法、总酚具有更高的一致性,如采用A280测定总酚,应采用MCP法测定缩合单宁。

Objective： Two most common methods for the determination of condensed tannins in wine： methylcellulose precipitation（MCP） assay and Adams-Harbertson（A-H） protein precipitation assay were compared with each other to find a rapid and accurate method.Methods： Condensed tannins in 32 red and 12 white wine samples from different varieties and different growing regions were determined separately by MCP assay and A-H assay to obtain average condensed tannin content and coefficient of variation.Determination of condensed tannin content in these samples was also carried out using HPLC-MS.In addition,total phenolic content（expressed as absorbance at 280 nm） was spectrometrically determined.Results： Both assays were suitable for the determination of condensed tannins in red wine rather than white wine.The MCP assay,although accurate,did not show a significant variation.The average condensed tannin content measured by the MCP assay was 9.13 times higher than that measured by the A-H assay,and a good linear correlation was observe between both assays（R2 = 0.6029,P0.01）.Moreover,the MCP assay showed a good linear correlation with HPLC-MS（R2= 0.7733,P0.01） but there was no significant correlation between the A-H assay and HPLC-MS（R2= 0.4843,P0.01）.A significant correlation between the content of condensed tannins determined by the MCP assay and the content of total phenols was observed（R2 = 0.9095,P0.01）,but the content of condensed tannins determined by the A-H assay and the content of total phenols revealed a poor correlation with each other（R2= 0.2872,P0.01）.Conclusion： Both assays can be used to determine condensed tannins in red wine.However,the MCP assay is a better method for the determination of condensed tannins in case that the content of total phenols is determined based on absorbance at 280 nm.