What on earth is acrylamide, the carcinogen in coffee?

A California court recently ruled that coffee products sold in California need to be labeled "acrylamide" as a carcinogen. Before understanding coffee and acrylamide, let's look at what acrylamide is! What happens when you ingest this substance?

acrylamide profile

Acrylamide is a product of the Menard reaction. Due to the influence of factors such as the acidity, water activity and food composition of food, it will be produced at a temperature above 120 degrees Celsius. It is a very common "toxin" in food, from potato chips to baked bread.

In 1994, the International Agency for Research on Cancer established the carcinogenicity of acrylamide in animal experiments, so although the World Health Organization classified acrylamide as a Class 2A carcinogen: "established carcinogenicity to animals, human may be carcinogenic."

However, some scholars believe that whether acrylamide is a carcinogen in humans still needs to be further established. In addition, acrylamide is also neurotoxic, affecting physiological functions such as cognitive behavior and memory.

However, because it is extremely common, we often ingest such carcinogens in our daily diet, so acrylamide content in food has always been a hot topic, from the brown sugar incident last year, last year's toast news to this year's coffee, are focused on acrylamide.

How does acrylamide form?

Although the Mena reaction can summarize the generation of acrylamide, but in fact the generation path of acrylamide is very many, in principle there are "carbonyl compounds"(carbonyls)+"specific amino acids"+"higher than 120 degrees Celsius" and other three conditions have the opportunity to generate, and this will also affect the food industry, using which ways to reduce the generation of acrylamide, and the path arrangement is as follows:

The mechanism of acrylamide formation. (Photo/Provided by Good Food Class)

"Reducing sugar"+"asparagine": This is the most common source, reducing sugar in food, such as: glucose, fructose, in the heating process will form acrylamide with asparagine (asparagine), so there are radical modification technology to reduce the asparagine content of potatoes, can greatly reduce the formation of acrylamide in French fries and potato chips.

"Sucrose cleavage": During heating, sucrose is cleaved to form 5-hyrdroxy-2-methylfurural (5-HMF), which can further react with asparagine to form acrylamide.

Acrylamide is a substance that is easily accessible in daily life. (Photo/Provided by Good Food Class)

"Fatty acid oxidation": not only "reducing sugar" will react to acrylamide, the key is not to form "carbonyl compounds", fatty acids in food, such as linoleic acid after heating, oxidation will produce cracking products, these are also "carbonyl compounds"(carbonyls), can be further synthesized with asparagine acrylamide.

"Acrylic acid generation": Acrylic acid (acrylic acid), can be produced by triglyceride free glycerol (glycerol), amino acid (aspartic acid, alanine), etc., further acrylic acid can be produced acrylamide.

3-Aminopropionamide: 3-APA is produced by enzymatic decarboxylation of asparagine, which can continue to react to acrylamide. In nature, asparagine in some crops is enzymatically formed into 3-APA, which leads to a greatly increased rate of acrylamide production in subsequent processing, which may explain why some foods have low asparagine content but also produce acrylamide.

From these production conditions, containing sugar (reducing sugar or sucrose), fat, protein, etc., coupled with the temperature of 120 degrees, acrylamide may be produced, which also means that acrylamide is very easy to contact in daily life substances.

The mechanism of acrylamide formation. (Photo/Provided by Good Food Class)

Sources of acrylamide in daily life

The European Food Safety Authority (EFSA) report investigated the main sources of acrylamide in various ethnic groups.

Adults: baked potato products (49%), coffee (34%), bread (23%).

Children and Adolescents: Baked potato products (51 percent, excluding potato chips), cereal and potato-related products such as breakfast cereals and breads (25 percent), processed cereal baby foods (14 percent, toddlers), cakes and pastry products (~ 15 percent, children and adolescents), potato chips and snacks (11 percent).

Infants: non-cereal baby foods (60%), potato products (48%) and cereal baby foods.

Although the survey results are mainly potato related products, but this also needs to consider potato varieties and cooking methods, not all, but Taiwanese do not eat potato products as a staple food, so potatoes are not necessarily the main source of acrylamide in Taiwan.

In 2013, the Food and Drug Administration of the Ministry of Health and Welfare conducted a survey on acrylamide in commercially available foods. The highest content was potato chips, with an average content of 114.6 μg per 100 grams, French fries of 28.4 μg, potato cakes of 55.4 μg and brown sugar of 84.7 μg.

▲ Potato chips have higher acrylamide content. (Photo/Provided by Good Food Class)

Problem of acrylamide content in vegetables

Compared to these snacks, fried vegetables are easier to ignore in daily life! In comparison with Hong Kong, which has a more similar diet to Taiwan, the Hong Kong Centre for Food Safety investigated the source of acrylamide and found that 52.4% came from vegetables and vegetable products.

The Hong Kong Food Safety Center analyzed several types of vegetables, and acrylamide could not be detected in eight kinds of "raw","boiled" and "steamed" vegetables. However, because fried vegetables can meet the requirements of "reducing sugar","asparagine" and "temperature", acrylamide can be detected in many fried vegetables samples.

Interestingly, the results of sampling in the restaurant found that the acrylamide content of the same color was much less, and it was found that the vegetables in the restaurant would be blanched for about 1 minute before frying, which could reduce the subsequent cooking time and reduce the production of acrylamide relatively.

▲ Problem of acrylamide content in vegetables. (Photo/Provided by Good Food Class)

Acrylamide limit?

The EFSA literature states that since every genotoxic substance can damage DNA and cause cancer problems, EFSA scientists believe it is impossible to set an upper limit for acrylamide intake in food. In 2011, the California government set an intake limit of 140 micrograms per kilogram per person per day, and there are also estimates of 2.6 micrograms from animal experiments, so there is no recognized upper limit for acrylamide intake.

In the Hong Kong survey, the daily intake is about 0.21 micrograms (per kilogram of body weight), while Professor Ye Anyi of National Taiwan University said in a previous interview that the intake of children in Taiwan is higher than that of adults, and the largest sample size is about 1.3 micrograms per person per day, which is lower than the current limit.

The type of coffee, roasting method, preservation, etc. will affect the acrylamide content. (Picture/Dazhi Schematic Diagram)

Finally, a brief analysis of the acrylamide problem of coffee, coffee varieties, baking methods, preservation and so on will affect the acrylamide content, and research analysis of freshly ground coffee, instant coffee acrylamide content, a cup of 160ml coffee contains 0.45 and 0.93 micrograms of acrylamide, compared to potato chips and French fries, or fried vegetables content, I do not think it is a critical number, so there is no need to worry!

Although acrylamide has not yet set an upper limit for intake, experts and scholars still believe that the lower the intake of such substances, the better. At present, the Ministry of Health and Welfare has developed a "Processing Reference Manual for Reducing Acrylamide Content in Food", which can be followed by food processors and reduce our exposure opportunities.