Why it's best to avoid overly burnt food

When food is severely burned , especially meat, bread, potatoes, or other starchy foods, the intense heat can release potentially harmful substances. Particularly dangerous to health are acrylamide , which forms especially in starchy foods during high-temperature cooking (frying, baking, toasting), and PAHs (polycyclic aromatic hydrocarbons) and heterocyclic amines , which can form especially when meat and other foods are cooked at very high temperatures or in direct contact with flames and smoke.

Acrylamide

The most dangerous substance released by burnt foods is called acrylamide, and according to several studies, it is genotoxic, meaning it can alter DNA, and potentially carcinogenic. It forms naturally during industrial cooking, but also at home and in wood-fired ovens: the food turns a brownish color.

Acrylamide has been classified by the International Agency for Research on Cancer (IARC) as "probably carcinogenic to humans," and the European Food Safety Authority (EFSA) recommends limiting its consumption. Once ingested, acrylamide spreads throughout the gastrointestinal tract. Laboratory tests on animals exposed to this substance have shown an increased risk of developing breast , testicular, lung, ovarian, skin, and stomach cancers .

In animals, exposure to acrylamide has in fact increased the occurrence of tumors, as documented by the indications of the European Food Safety Authority, according to which acrylamide is defined as "a cause of concern for public health".

Polycyclic aromatic hydrocarbons (PAHs)

Polycyclic aromatic hydrocarbons are formed during the combustion or high-temperature decomposition of organic matter. When you grill meat, for example, the fat drips onto the flame , producing smoke and combustion products containing PAHs; the smoke can deposit them on the surface of the meat.

Some PAHs, such as benzo[a]pyrene , are genotoxic and carcinogenic . In other words, they can be transformed in the body into molecules capable of interacting with and damaging DNA.

HCAs (heterocyclic amines) , on the other hand, are formed mainly when meat, fish, or poultry are cooked at high temperatures , such as grilling, pan-frying, or on a griddle. They result from reactions between amino acids, sugars, and components typical of muscle tissue. According to National Cancer Institute guidelines , these substances can also be mutagenic : after being metabolized, they can generate reactive compounds capable of damaging DNA. In animal studies, high exposures have caused tumors.

The pizza was too burnt

A classic food that can turn out burnt is wood-oven pizza. Opinions on this specific dish are quite divergent. According to a September 2023 study conducted by the Federico II University of Naples and published in the scientific journal Food , the burnt crust of pizza does not release significant amounts of acrylamide. The study, titled “Asparaginase enzyme reduces acrylamide levels in fried and wood-oven baked pizza base ,” investigated whether it was possible to reduce acrylamide in pizza by adding the enzyme L-asparaginase to the dough.

The reason is interesting: during high-temperature cooking, the asparagine in flour can react with sugars through the Maillard reaction and contribute to the formation of acrylamide. L-asparaginase converts asparagine into other substances that do not participate in the formation of acrylamide.

Of particular note is that in untreated pizzas, the researchers measured approximately 2.210 µg/kg of acrylamide in wood-fired pizza and 3.150 µg/kg in fried pizza, in their respective experiments.

In any case, the advice is not to overdo it with the burnt pizza and simply scrape off the darker spots with a knife to remove them.

How to avoid overly burnt foods

To prevent food from burning and releasing acrylamide, some precautions must be taken during cooking:

• Don't overdo the frying temperature: it shouldn't exceed 175 degrees, and avoid the food turning brown.
• Use the natural yeast to make all baked goods at home.
• The bread should be toasted for no more than three minutes.
• Blanch the potatoes before frying them, and avoid cutting them into very small pieces which can brown more easily during cooking.
• Potatoes for frying should preferably be freshly picked and stored at a temperature above 8 degrees.
• Where possible, prefer methods of steam cooking or stewing in a pan, instead of frying or baking.
• If the food is burnt, the simplest thing to do is to remove the blackened parts before eating it.

The goal of correct cooking, with which the flavor of the food is expressed at the maximum level and the risk of burnt foods is eliminated, is a well-cooked and golden, but not charred, surface.

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