Acrylamide is a polymerized compound that chemists and biologists can use to analyze protein sizes and make plastics. But it also forms in small amounts in foods that are cooked at high temperatures. This what was discovered in 2002 by scientists when foods undergo the Maillard reaction. For example, the temperatures used for roasting coffee beans kickstarts a series of reactions that leads to acrylamide formation. Prior to this finding, the primary known potential sources of acrylamide had been tobacco smoke and drinking water.
In the West, consumption of coffee (13-39%), fried potato chips (16-30%), potato crisps (6-46%), pastries and sweet biscuits (10-20%), bread and crisp bread (10-30%), and to a lesser extent other foods (10%), are the main causes of exposure to acrylamide. In the United States, the exposure is attributed to fried potato products (37%), and coffee (7%).
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But is acrylamide in coffee dangerous? Well, its toxicity to humans are currently unknown. But one certain thing is the levels of acrylamide in food. This depends on many processing variations and parameters. Temperature, time, frying oil type, and food matrix type all play a part in its formation.
Here is how acrylamide forms in coffee.
HOW DOES ACRYLAMIDE FORM?
Generally, foods heated above 284°F (120°C) by baking, frying, and broiling produce various reactions that lead to reactions, particularly the Maillard reaction. Studies confirmed that fresh foods or not cooked contain no quantifiable amount of acrylamide. In the case of coffee, acrylamide only forms during roasting of coffee beans. Studies have revealed that acrylamide forms in brewed coffee, coffee substitutes, and instant coffee.
The Maillard reaction is a browning process wherein the reducing sugars and free amino acids in proteins react and consumed. Many studies have been conducted to determine the mechanisms of acrylamide formation. But the most important pathway is the decarboxylation and deamination of asparagine. Asparagine is one of the 20 amino acids, and found in nearly every food including coffee. In the presence of glucose, cysteine and methionine also form acrylamide, but the yields are much lower than those from asparagine.
In complex food systems, the reaction pathways for acrylamide formation are more complicated. It is because it extends beyond the simple reaction of reducing sugars with asparagine.
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Acrylamide does not form in unheated or even boiled foods, such as boiled potatoes, because the temperature does not rise above 212°F (100°C) during boiling. It does occur at very low levels in canned or frozen fruits and vegetables, as well as vegetable protein products.
ARE ACRYLAMIDE LEVELS IN COFFEE DANGEROUS?
Studies have revealed that a wide range of foods subjected to high heat contain acrylamide. The European Food Safety Authority (EFSA) mentioned that fried potatoes are the main contributor to total dietary exposure. Heated potatoes such as French fries and potato chips contain the highest levels potatoes contain both free reducing sugars and free asparagine. According to a data provided by the European Commission, potato crisps can contain about 628 μg/kg of acrylamide.
In coffee, the levels of acrylamide largely depend on the length and temperature during roasting. Coffee contains on average 249 to 253 μg of acrylamide. One study revealed that coffee substitutes contain the highest acrylamide level (818 μg/kg) followed by instant coffee (358 μ/kg) and then roasted coffee (179 μ/kg). So are these acrylamide levels in coffee dangerous?
Acrylamide is considered a toxin, but at concentrations higher than those found in foods (including coffee). Furthermore, several studies that have been done so far on acrylamide effects in rodents involved concentrations a thousandfold higher than those found in food. Hence, it is still unclear if these levels pose risk to the human health.
But there are some hints on increased risk of developing some type of cancer. A 1994 report by the International Agency for Research on Cancer (IARC) stated that acrylamide causes chromosomal aberrations, gene mutations, and cell transformation in rodents. This led to the conclusion that acrylamide is most likely carcinogenic to humans. The organization then classified acrylamide as a potential human carcinogen (group 2A). The Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives (JECFA) said that it is indeed a human health concern.
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But presently, the full impact of acrylamide on the human health is still unknown. More research is needed before any definitive conclusions can be drawn about the potential dangers of acrylamide in foods. The JECFA suggested to conduct long-term studies on its potential impact.
REMOVING ACRYLAMIDE IN COFFEE
Acrylamide is an unstable compound that can be destroyed by the addition of nucleophilic amino or sulfhydryl groups from amino acids and other nucleophiles. For this reason, the reported levels of acrylamide are thus the outcome of simultaneous formation and elimination reactions.
But if truth be told, removing acrylamide in coffee in impossible since if forms during roasting, the essential step that brings out the aroma and flavor of coffee. The good news is that the maximum exposure levels of acrylamide (as per EFSA recommendation) is far from what people normally consume. Even so, there are several proven ways to reduce its levels in coffee.
At home, there are steps you can take to reduce your intake to significantly lower the levels of acrylamide from coffee. One strategy is to lengthen the duration of roasting the beans. The longer the roasting duration of coffee beans, the lower the level of acrylamide formation. Acrylamide formation peaks during the early part of the roasting process. Over time, the rate of acrylamide formation slows down, and the extended roasting time allows the high temperature to break down the acrylamide that has formed. In fact, this 2004 Austrian study found that coffee beans roasted for longer time form less acrylamide. This same study also concluded that raising the roasting temperature helps lower acrylamide formation.
Another way to reduce acrylamide intake is to opt for fresh roasted coffee, instead of coffee substitutes and instant coffee. According to earlier mentioned study, it found that fresh roasted coffee contains 179 μ/kg of acrylamide. But instant coffee contains twice as much, while coffee substitutes contain thrice the amount of the chemical.
What most studies suggest is to select commercial blends with higher arabica percentages. Arabica coffee contains lower asparagine concentrations than Robusta species. For this reason, Arabica coffee when roasted tends to contain less acrylamide.
To sum it up, lower asparagine concentrations, higher roasting temperatures, and longer roasting times all result in lower acrylamide levels in coffee.
