Polyphenols in dark chocolate

Dark chocolate contains natural compounds that possess biological functions and serve as antioxidants. These compounds include polyphenols, flavanols, catechins, and others.

Given its high concentration of polyphenols, dark chocolate offers a substantial source of antioxidants that have the potential to regulate blood sugar levels, counter oxidative damage, enhance the immune system, and lower the risk of heart disease. Research indicates that when consumed alongside foods like almonds and cocoa, the polyphenols present in dark chocolate could contribute to reducing specific types of LDL cholesterol.

The polyphenols derived from cocoa may also act as protective measures against diseases in which oxidative stress is implicated, such as cancer. Additionally, these polyphenols exhibit effects that impede excessive cell proliferation, counteract mutations, provide defense against chemical harm, and even play a role in preventing tooth decay.

Studies detailed in the journal Molecules (2009;14:200–209) have confirmed the connection between the amount of cocoa mass in chocolate and the content of polyphenols. In dark chocolate, the polyphenol content was measured at 578 mg/100 g, while milk and white chocolates contained 160 mg/100 g and 126 mg/100 g, respectively.
Polyphenols in dark chocolate

Cocoa polyphenols

Cocoa and cocoa products, namely cocoa liquor, cocoa powder and chocolates (milk and dark chocolates) may present varied polyphenol contents and possess different levels of antioxidant potentials.

Fresh cocoa beans contain about 32–39% water, 30–32% fat, 10–15% protein, 5–6% polyphenols, 4–6% pentosans, 2–3% cellulose, 2–3% sucrose, 1–2% theobromine, 1% acids and less than 1% caffeine. It is also a rich source of mineral components.

The polyphenols in cocoa beans could contribute to about 12-18% of the dry weight of the whole bean.

The content and composition of polyphenols differs depending on the genotype, origin, growth conditions, degree of ripeness of the cocoa fruit and the grain processing parameters.

Studies indicated that dark chocolate exhibited the highest polyphenol content, with 610 mg total catechins/kg of fresh edible weight. With advancements in technology, high performance liquid chromatography (HPLC) had been utilized in the determination of polyphenol compounds in cocoa.

Main classes of polyphenolic compounds identified are such as simple phenols, benzoquinones, phenolic acids, acetophenones, phenylacetic acids, hydroxycinnamic acids, phenylpropenes, coumarines, chromones, naphtoquinones, xanthones, stilbenes, anthraquinones, flavonoids, lignans and lignins. Three main groups of cocoa polyphenols can be distinguished namely the catechins (37%), anthocyanins (4%) and proanthocyanidins (58%).

The brown and purple color of the cocoa bean was attributed to the complex alteration products of catechin and tannin. Beside these compounds, cocoa was found to have leucoanthocyanins that are present as glycosides.

Phenolic antioxidants have been shown to inhibit the oxidation of low-density lipoprotein (LDL) cholesterol, and mounting evidence suggests that it is the oxidized form of LDL that leads to the buildup of fatty plaques in arteries.

Some other the beneficial effects of polyphenols are such as anti-carcinogenic, anti-atherogenic, anti-ulcer, anti-thrombotic, anti-inflammatory, immune modulating, anti-microbial, vasodilatory and analgesic effect.

Epicatechin and other flavonoids not only have a direct antioxidant effect, but they may also have a sparing effect on other antioxidants such as Vitamin C and E.
Cocoa polyphenols

Flavonoids in dark chocolate

The beneficial plant compounds in chocolate are called flavonoids, which contribute to the dark pigment in chocolate. Flavonoids are polyphenolic compounds found abundantly in cocoa.

Dark chocolate contains a high percentage (equal to 70 percent) of cocoa solids, and little or no added sugar. As a result, dark chocolate contains more health benefits. At the contrary, milk chocolate contains less flavonoids as evidenced by its lighter color.

Cocoa flavonoids are classified as flavanols and include the monomers, (-)-epicatechin, (+)-catechin, and procyanidins, the oligomers of these monomeric units. Flavonoids occur naturally in the cocoa plant as a way of protecting the plant. Their presence affects the taste of chocolate and they are responsible for the astringency in the unprocessed cocoa bean.

The flavonoid found in dark chocolate has been linked to decreases in blood pressure, improvements in endothelial dysfunction that promote vascular homeostasis, improvements in antiplatelet activity, improvements in insulin sensitivity, increases in high-density lipoprotein (HDL) cholesterol concentrations, improvements in cognitive, and antioxidant properties.

Furthermore, an increase in plasma antioxidant capacity and a decrease in plasma oxidation products are associated with elevated epicatechin concentrations. Research recently reported that the cocoa flavonoids decrease plasma leukotriene-prostacyclin ratios in human plasma and aortic endothelial cells (Journal of the American College of Nutrition, Vol. 23, No. 3, 197–204, 2004).
Flavonoids in dark chocolate

Epicatechins compound

The main groups of cocoa polyphenols are catechins or flavn-3-ols (catechin and epicatechin), proanthocyanidins and anthocyanins in low proportion. Epicatechin represent 2-4% of the dry weight of defatted cocoa seeds powder.

Dark chocolate with its high cocoa content is a rich source of epicatechin and gallic acid, which are thought to poses cardioprotective properties.

In human consuming, cocoa, plasma level of non-methylated epicatechins such as epicatechin-7-sulfate and methylated metabolites such as 3’-O-methylepicatechin have been reported to occur in micromolar concentration within 1 hr after intake.

Epicatechin has been found to reduce brain damage in mice when given ninety minuets before or up to three and a half hour after ischemic stroke, possibly by activating two pathways, Nrf2 and heme oxygenase.
Epicatechins compound

Polyphenols in chocolate and its functions

These polyphenols, mainly flavonoids with as catechin (flavan-3-ols), epicatechin and procyanidins, give chocolate antioxidant activity. Chocolate also contains additional flavonoids not found in tea, with high concentrations of oligomeric procyanidins.

Chocolates contain both a high quality and a high quantity of phenol antioxidants. Depending on the anthocyanin content, the pigmentation in polyphenol-storage cells ranges from white to deep purple.

Human studies have confirmed that polyphenols in chocolate are indeed bioavailable and able to increase the antioxidant capacity of plasma, with one study reporting that ingestion of 80 g of procyanidin rich-chocolate increased plasma epicatechin concentrations 12-fold.

Polyphenols and alkaloids, ~14 - 20% bean weight, are central to bean flavor character. Three groups of polyphenols can be differentiated: catechins or flvan-3-ols (~37%), anthocyanins (~4%) and proanthocyanidins (~58%).

Dark chocolate has the highest total catechin content, with approximately 53.5 mg/100 g, whereas milk chocolate contains approximately 15.9 mg/100 g. White chocolate primarily contains cocoa butter with minimal levels of polyphenols.
Polyphenols in chocolate and its functions