Andres-Lacueva C, Monagas M, Khan N, Izquierdo-Pulido M, Urpi-Sarda M, Permanyer J, Lamuela-Raventós R M
Departament de Nutrició i Bromatologia, XARTA, INSA Facultat de Farmàcia, Universitat de Barcelona, Av. Joan XXIII s/n, Barcelona 08028, Spain.
J Agric Food Chem. 2008 May 14;56(9):3111-7. doi: 10.1021/jf0728754. Epub 2008 Apr 16.
Major brands of cocoa powder products present in the Spanish market were analyzed for monomeric flavanols [(+)-catechin and (-)-epicatechin] and flavonols [quercetin-3-glucuronide, quercetin-3-glucoside (isoquercitrin), quercetin-3-arabinoside, and quercetin]. In addition, the influence of the manufacturing process of cocoa powder products, in particular, the alkalinization treatment ( Dutching), on the original content of these flavonoids has been studied. (-)-Epicatechin was in the range of 116.02-730.26 microg/g, whereas (+)-catechin was in the range of 81.40-447.62 microg/g in the commercial cocoa products studied. Among flavonols, quercetin-3-arabinoside and isoquercitrin were the major flavonols in the cocoa powder products studied, ranging from 2.10 to 40.33 microg/g and from 3.97 to 42.74 microg/g, respectively, followed by quercetin-3-glucuronide (0.13-9.88 microg/g) and quercetin aglycone (0.28-3.25 microg/g). To our knowledge, these results are the first quantitative data in relation to the content of individualized flavonol derivatives in commercial cocoa powder products. The alkalinization treatment resulted in 60% loss of the mean total flavonoid content. Among flavanols, (-)-epicatechin presented a larger decline (67%, as a mean percentage difference) than (+)-catechin (38%), probably because of its epimerization into (-)-catechin, a less bioavailable form of catechin. A decline was also confirmed for di-, tri-, and tetrameric procyanidins. In the case of flavonols, quercetin presented the highest loss (86%), whereas quercetin-3-glucuronide, quercetin-3-arabinoside, and isoquercitrin showed a similar decrease (58, 62, and 61%, respectively). It is concluded that the large decrease found in the flavonoid content of natural cocoa powder, together with the observed change in the monomeric flavanol profile that results from the alkalinization treatment, could affect the antioxidant properties and the polyphenol biovailability of cocoa powder products.
对西班牙市场上主要品牌的可可粉产品进行了分析，以测定其中的单体黄烷醇[（+）-儿茶素和（-）-表儿茶素]和黄酮醇[槲皮素-3-葡萄糖醛酸苷、槲皮素-3-葡萄糖苷（异槲皮苷）、槲皮素-3-阿拉伯糖苷和槲皮素]含量。此外，还研究了可可粉产品制造工艺，特别是碱化处理（荷兰化处理）对这些黄酮类化合物原始含量的影响。在所研究的市售可可产品中，（-）-表儿茶素含量在116.02-730.26微克/克范围内，而（+）-儿茶素含量在81.40-447.62微克/克范围内。在黄酮醇中，槲皮素-3-阿拉伯糖苷和异槲皮苷是所研究可可粉产品中的主要黄酮醇，含量分别在2.10至40.33微克/克和3.97至42.74微克/克之间，其次是槲皮素-3-葡萄糖醛酸苷（0.13-9.88微克/克）和槲皮素苷元（0.28-3.25微克/克）。据我们所知，这些结果是关于市售可可粉产品中个别黄酮醇衍生物含量的首批定量数据。碱化处理导致黄酮类化合物平均总含量损失60%。在黄烷醇中，（-）-表儿茶素的下降幅度更大（平均百分比差异为67%），高于（+）-儿茶素（38%），这可能是因为它异构化为（-）-儿茶素，而后者是儿茶素生物利用度较低的一种形式。二聚体、三聚体和四聚体原花青素也出现了下降。就黄酮醇而言，槲皮素的损失最高（86%），而槲皮素-3-葡萄糖醛酸苷、槲皮素-3-阿拉伯糖苷和异槲皮苷的下降幅度相似（分别为58%、62%和61%）。得出的结论是，天然可可粉中黄酮类化合物含量大幅下降，以及碱化处理导致的单体黄烷醇谱变化，可能会影响可可粉产品的抗氧化性能和多酚生物利用度。
