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Coffee and Antioxidant Relationship: Physics and Chemistry of the Process


The internet is full of articles on how good coffee is for its antioxidants. But few people know what antioxidants are, how they affect the body, and why they are needed.

What are antioxidants?

Surprising but true: antioxidants are not substances of a single chemical group. Also, the variety of organic substances that can act as antioxidants is surprising. There is something that unites them: all antioxidants slow or suppress the oxidation process of other organic compounds.

Initially, the ability to suppress oxidation was used not in medicine, but in manufacturing. The largest industry in which antioxidants were used was the fuel industry. Gasoline and other petroleum-based fuels are easily exposed to oxygen as they are organic substances, so small amounts of paraoxydiphenylamine, alpha-naphthol, etc. can be added to them to prevent degradation.

Later, antioxidants started to be used in food production to increase the shelf life of products. Allowed additives are propyl gallate (E310), butylhydroxyanisole (E320), the well-known ascorbic acid (E300) and many other "essi" simply antioxidants.

Antioxidants and Free Radicals: Physics and Chemistry of the Process

In the mid-1950s, gerontologist Denham Harman, who studied the aging process, theorized that the human body ages because of the constant damage done to cells by free radicals. By free radicals he meant any molecule or atom containing one or more unpaired electrons at the external electronic level. According to Harman's theory, the accumulation of damage from radicals ultimately leads to cell aging.

Free radicals with unpaired electrons "tend" to have all electrons paired. They "take" electrons, reacting with neighboring molecules, forming new free radicals (and continuing along the chain). It is bad that the molecule that becomes a free radical changes its charge (+ or -) and stops performing its function in the cell. Antioxidants cannot "beat" oxidation, but they slow the rate of formation of the same new chain of free radicals.


The free radical theory of aging has yet to be conclusively proven (although the fact that Denham Harman lived to be 98 years old is very important), but scientists have found that free radicals damage cells, as well as indirect culprits of cancer. arthritis, atherosclerosis, diabetes, Alzheimer's disease etc. Thus, you can stop the development of these diseases by using antioxidants as a prophylactic or during treatment.

Antioxidant activity of coffee

Coffee antioxidants, tannins, are phenolic compounds with tannic properties. Unroasted grains contain 3.6% to 7.7% tannin in the roasted state - 0.5% to 1%. It is tannins that are responsible for the rich natural bitter taste of coffee. Other antioxidants in coffee are chlorogenic, caffeic and ferulic acids.

By examining the antioxidant activity of coffee using the amperometric method, scientists found that 2-3 cups of coffee beans a day are enough to meet the body's daily antioxidant needs.

Meanwhile, studies have shown that coffee drinkers have a 65% lower risk of developing Alzheimer's disease in old age (and this is the most common cause of senile dementia) than non-coffee drinkers.

Which coffee is healthier?

Antioxidant activity (AA) depends on the type of coffee, the country of origin and terror, the degree of roasting and the method of preparation.

The AA of green (unroasted) Arabica is 366 ± 74 (mg per cup), Robusta is 643 ± 68, but roasting almost equals the antioxidant activity. In addition, due to the structure of roasted coffee, it is almost impossible to obtain useful substances. Only heat treatment at very high temperatures (i.e. roasting) "awakens" antioxidants and other substances that are in a "dormant" state in the hard green grains. At the same time, roasting stops the fermentation of the raw grain and destroys any bacteria left over after harvesting, processing and shipping.

The most useful are Arabica and Robusta light roasts (AA is 280-290). AA medium roast coffee is 190-200, dark roast coffee is about 135-168. The healthiest coffee is light (Scandinavian) roasted coffee.

But coffee with milk contains the least amount of antioxidants because the milk protein casein reacts with tannins and reduces their effectiveness.

Looks like it's time for a cup of coffee...

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