Marseglia A, Acquotti D, Consonni R, Cagliani L R, Palla G, Caligiani A
Department of Food Science, University of Parma, Parco Area delle Scienze 17/A, 43124 Parma, Italy.
Centro Interdipartimentale Misure, University of Parma, Parco Area delle Scienze 23/A, 43124 Parma, Italy.
Food Res Int. 2016 Jul;85:273-281. doi: 10.1016/j.foodres.2016.05.001. Epub 2016 May 4.
Chocolate and cocoa-based products are among the goods with higher added value. A current trend of the cocoa market is to offer to the consumers high quality cocoa products, namely mono-origin cocoa. However, a reliable analytical method able to trace the geographical origin of cocoa is lacking. In this work we tested the capability of HR MAS H NMR combined with chemometrics to assess the geographical origins of 60 fermented and dried cocoa beans of 23 different cocoa producing countries from the three major crop-growing areas (Africa, Central/South America, Asia/Oceania). Metabolic profiling was determined by HR MAS H NMR directly on cocoa powder after the method optimization. The same samples were also subjected to extraction and analysis with HR H NMR. HR MAS H NMR, as H NMR analysis, allowed the simultaneous detection of amino acids, polyalcohols, organic acids, sugars, methylxanthines, catechins. Moreover, HR MAS allows the detection of lipids, not present in the aqueous extract utilized for H NMR. The data set obtained is therefore representative of all classes of cocoa compounds. Untargeted HR MAS H NMR and H NMR datasets were utilized as fingerprint of the samples and elaborated with multivariate statistical methods. A targeted quantitative approach of selected metabolites was possible only with HR H NMR data, because HR MAS H NMR does not give reliable quantitative results. All the approaches adopted showed a discrimination of the cocoa origins. HR MAS presents the advantages to obtain a very rapid picture of the samples, comprising both lipophilic and hydrophilic components, avoiding any sample manipulation.
巧克力和可可制品属于高附加值商品。可可市场当前的一个趋势是向消费者提供高品质的可可产品，即单一产地可可。然而，目前缺乏一种能够追踪可可地理来源的可靠分析方法。在这项工作中，我们测试了高分辨魔角旋转氢核磁共振（HR MAS H NMR）结合化学计量学评估来自三大作物种植区（非洲、中美洲/南美洲、亚洲/大洋洲）23个不同可可生产国的60颗发酵和干燥可可豆地理来源的能力。在方法优化后，通过直接对可可粉进行HR MAS H NMR测定代谢谱。同样的样品也进行了高分辨氢核磁共振（HR H NMR）提取和分析。与H NMR分析一样，HR MAS H NMR能够同时检测氨基酸、多元醇、有机酸、糖类、甲基黄嘌呤、儿茶素。此外，HR MAS能够检测出用于H NMR的水提取物中不存在的脂质。因此，所获得的数据集代表了所有类别的可可化合物。未靶向的HR MAS H NMR和H NMR数据集被用作样品的指纹图谱，并采用多元统计方法进行处理。只有利用HR H NMR数据才能对选定代谢物进行靶向定量分析，因为HR MAS H NMR无法给出可靠的定量结果。所采用的所有方法都显示出对可可来源的区分能力。HR MAS具有优势，能够非常快速地呈现样品的全貌，包括亲脂性和亲水性成分，且无需对样品进行任何处理。
