Cocoa is a food rich in polyphenols, mainly the flavonoid procyanidins and flavan-3-ols. The improvement of the cardiovascular function in humans upon cocoa consumption has been specifically linked to the presence of flavan-3-ol derived metabolites in plasma, especially epicatechin glucuronide. In this context, a flavonoid-enriched cocoa-derived product could potentially exert stronger health benefits. The aim of the present study was to obtain a cocoa powder with a higher flavonoid content (mainly enriched in monomer compounds) and assess its flavonoid bioavailability in humans. For this purpose, an unfermented, nonroasted, and blanch-treated cocoa powder (A) was obtained. The powder contained four times more procyanidins than a conventional (B) cocoa powder. Powder A contained eight times more epicatechin and procyanidin B2 than powder B. Cocoa milk drinks were prepared with powder A (MDA) and B (MDB). The bioavailability of flavonoids in both drinks was assessed in a crossover intervention with healthy volunteers. The content of epicatechin glucuronide, the main metabolite detected in plasma, was five-fold higher upon consumption of MDA as compared with MDB. The urinary excretion of metabolites, mainly methyl epicatechin sulfate, was higher upon MDA consumption as compared with MDB, ranging from two-to 12-fold higher depending on the metabolite. These results, together with previous reports regarding the cardiovascular benefits linked to the presence of procyanidin metabolites in plasma, suggest that further clinical trials to validate the health benefits of a flavonoid-enriched cocoa powder are warranted.

a b s t r a c tFermentation and roasting are the main causes of polyphenol degradation during the process for obtaining cocoa products. In the present study, a process for obtaining polyphenol-rich cocoa products on an industrial scale is described. The process avoids the fermentation and roasting steps and includes a step for the inactivation of the enzyme Polyphenol Oxidase (PPO), which helps preserve the polyphenol content present in the raw cocoa bean. In addition, our study evaluates the antioxidant capacity and characterizes the flavonoid profile of the polyphenol-rich cocoa products obtained from the natural polyphenolrich cocoa cake. Using different protocols, we have obtained three cocoa extracts with high polyphenol content, namely extracts A (167 mg/g), B (374 mg/g) and C (787 mg/g). The scavenging capacity of the extracts was measured as their ability to bleach the stable radicals DPPH Å and ABTS Å+ while their antioxidant effect was evaluated with the FRAP assay. The results for A, B and C in the DPPH test expressed as Trolox equivalent (lmol)/mg dry weight of extract were 0.2, 1.4 and 3.0, respectively; in the ABTS test the results were 1.0, 4.7 and 9.8. The antioxidant capacity expressed as ascorbic acid equivalent (lmol)/mg dry weight of each product were 17.2, 76.1 and 207.7, respectively. The scavenging properties of cocoa powder against the superoxide anion, H 2 O 2 , HClO, and peroxynitrite were also determined. The IC 50 (lg/mL) values in the hypoxanthine/xanthine oxidase test were 77.5, 12.3 and 10.3, for A, B and C, respectively, while as an HOCl scavenger the IC 50 (lg/mL) values were 225.4, 73.2 and 21.5. As a peroxynitrite anion scavenger, only extract C had a relevant effect, with IC 50 (lg/mL) values of 76.1 or 110.0 in the absence or presence of bicarbonate. None of the extracts tested showed activity in the hydrogen peroxide test, but B and C significantly increased the deoxyribose degradation in the absence of ascorbate. Likewise, none of the extracts inhibited the ferrous or copper chelating activity at 100 lg/mL, but they inhibited the lipid peroxidation in brain homogenates and human plasma through non-enzymatic generation systems, with extract C giving the best IC 50 (lg/mL) values: 17.4 and 8.1 against lipid peroxidation in brain homogenates and human plasma, respectively. In conclusion, if the extractive protocol is well characterized, defined and optimized, cocoa could constitute a source of polyphenols for enriching foods, nutraceuticals and alimentary supplements.

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