Hamburg School of Food Science, Institut für Lebensmittelchemie, Universität Hamburg , Grindelallee 117, 20146 Hamburg, Germany.
J Agric Food Chem. 2014 Dec 17;62(50):12118-27. doi: 10.1021/jf504258w. Epub 2014 Dec 2.
Two cocoa types, Arriba and CCN-51, are being cultivated in Ecuador. With regard to the unique aroma, Arriba is considered a fine cocoa type, while CCN-51 is a bulk cocoa because of its weaker aroma. Because it is being assumed that Arriba is mixed with CCN-51, there is an interest in the analytical differentiation of the two types. Two methods to identify CCN-51 adulterations in Arriba cocoa were developed on the basis of differences in the chloroplast DNA. On the one hand, a different repeat of the sequence TAAAG in the inverted repeat region results in a different length of amplicons for the two cocoa types, which can be detected by agarose gel electrophoresis, capillary gel electrophoresis, and denaturing high-performance liquid chromatography. On the other hand, single nucleotide polymorphisms (SNPs) between the CCN-51 and Arriba sequences represent restriction sites, which can be used for restriction fragment length polymorphism analysis. A semi-quantitative analysis based on these SNPs is feasible. A method for an exact quantitation based on these results is not realizable. These sequence variations were confirmed for a comprehensive cultivar collection of Arriba and CCN-51, for both bean and leaf samples.
在厄瓜多尔种植了两种可可豆，分别是 Arriba 和 CCN-51。就独特的香气而言，Arriba 被认为是一种优质可可豆，而 CCN-51 的香气较弱，因此属于大宗可可豆。由于假设 Arriba 中混入了 CCN-51，因此人们对这两种类型的分析性差异产生了兴趣。基于叶绿体 DNA 的差异，开发了两种用于鉴定 Arriba 可可豆中 CCN-51 掺假的方法。一方面，反向重复区中序列 TAAAG 的不同重复导致两种可可豆类型的扩增子长度不同，这可以通过琼脂糖凝胶电泳、毛细管凝胶电泳和变性高效液相色谱检测到。另一方面，CCN-51 和 Arriba 序列之间的单核苷酸多态性 (SNP) 代表限制性位点，可用于限制性片段长度多态性分析。基于这些 SNP 的半定量分析是可行的。但基于这些结果进行精确定量的方法是不可行的。这些序列变异已在 Arriba 和 CCN-51 的综合品种收集以及豆和叶片样本中得到了证实。
