Hue Clotilde, Brat Pierre, Gunata Ziya, Samaniego Ivan, Servent Adrien, Morel Gilles, Kapitan André, Boulanger Renaud, Davrieux Fabrice
Valrhona SA, 8 quai du Général de Gaulle, 26600 Tain, L'Hermitage, France.
J Agric Food Chem. 2014 Oct 15;62(41):10136-42. doi: 10.1021/jf501070d. Epub 2014 Oct 6.
Flavan-3-ols were successfully extracted from cocoa by the Fast-Prep device and analyzed by HPLC-DAD, and their identifications were confirmed by injection of authentic standards. (-)-Epicatechin was the most abundant component with an average of 9.4 mg/g dried cocoa powder. More than 700 cocoa samples were used to calibrate the NIRS. An efficient calibration model was developed to accurately determine any flavan-3-ol compound of ground dried cocoa beans (SEP = 2.33 mg/g in the case of total flavan-3-ols). This performance enabled NIRS to be used as an efficient and easy-to-use tool for estimating the level of targeted compounds. The analysis of the PLS loadings of the model and pure epicatechin spectra gave proof that NIRS was calibrated on an indirect strong correlation resulting in the changes in flavan-3-ols during fermentation and their interaction with some major components, such as proteins. Total flavan-3-ol concentration fell from an average of 33.3 mg/g for unfermented samples to an average of 6.2 mg/g at the end of fermentation. Changes in flavan-3-ol content were dependent upon the origin and highly correlated to the fermentation level expressed as the sum of temperatures (average R(2) = 0.74), a good marker of the fermentation process and of the heterogeneity of the batch.
通过快速制备设备成功从可可中提取了黄烷 - 3 - 醇，并采用高效液相色谱 - 二极管阵列检测法（HPLC - DAD）进行分析，通过注入标准品对其进行了鉴定。（-）-表儿茶素是含量最丰富的成分，平均含量为9.4毫克/克干可可粉。使用了700多个可可样品对近红外光谱仪（NIRS）进行校准。开发了一种有效的校准模型，以准确测定磨碎的干可可豆中的任何黄烷 - 3 - 醇化合物（总黄烷 - 3 - 醇的情况下，标准误差（SEP）为2.33毫克/克）。这种性能使近红外光谱仪能够用作估算目标化合物含量的高效且易于使用的工具。对模型的偏最小二乘法（PLS）载荷和纯表儿茶素光谱的分析证明，近红外光谱仪是基于间接强相关性进行校准的，这种相关性导致发酵过程中黄烷 - 3 - 醇的变化及其与一些主要成分（如蛋白质）的相互作用。总黄烷 - 3 - 醇浓度从未发酵样品的平均33.3毫克/克降至发酵结束时的平均6.2毫克/克。黄烷 - 3 - 醇含量的变化取决于产地，并且与以温度总和表示的发酵水平高度相关（平均R² = 0.74），温度总和是发酵过程和批次异质性的良好指标。
