A few days ago, the topic #59 types of coffee were all tested for carcinogens# was on the hot search. The Fujian Provincial Consumer Council conducted a comparative test on 59 types of freshly made and sold coffee from 20 coffee sales units in Fuzhou City, and low levels were detected in all of them. The class 2A carcinogen "acrylamide". This news surprised "coffee lovers" and even began to hesitate whether to drink the coffee in their hands. Is the truth really that terrible? In this article, we will talk about "coffee causes cancer" and tell you which coffee has the least acrylamide. Let everyone choose the right coffee and drink coffee with confidence.
Why does coffee contain acrylamide? In fact, it is normal to detect acrylamide in coffee, which is related to the coffee processing process. Green coffee beans contain sucrose and asparagine, which undergo the Maillard reaction at high temperatures. Acrylamide is one of the by-products of the Maillard reaction. Under normal circumstances, acrylamide is easily produced when the cooking temperature is higher than 120°C, and coffee beans are almost always roasted above this temperature, so it is not surprising that acrylamide is present in coffee. Some researchers roasted green coffee beans at 125°C for 30 to 60 minutes. The acrylamide content gradually increased in the first half hour. When it was extended to 40 minutes, the acrylamide content was the highest. After continuing to roast for 50 and 60 minutes, the acrylamide gradually decreased. , but are slightly greater than the content at 30 minutes. However, it is precisely because of the Maillard reaction when roasting coffee beans that coffee has a unique aroma. The Maillard reaction produces more than 800 aroma substances, which together give coffee a complex and aromatic flavor. Which coffee has lower acrylamide? The amount of acrylamide in coffee can be affected by a variety of factors. Such as the type of raw materials, degree of roasting, processing methods, etc. 1. In terms of raw materials, different coffee beans produce different amounts of acrylamide after processing. Coffee varieties are mainly divided into small coffee beans (Arabica coffee), medium coffee beans (Robusta coffee) and large coffee beans (Libby coffee). Ricca coffee). Liberica coffee beans are generally unpopular and rarely used commercially due to their poor aroma, bitter flavor, and varying sizes. Among the remaining two types, roasted Arabica coffee has significantly lower acrylamide content than Robusta coffee. Yunnan arabica coffee, which is currently more popular on the market, is a type of Arabica coffee. 2. Roasting degree: The roasting degree of coffee beans is a key factor affecting the acrylamide content. Some researchers used the hot air method to roast Arabica coffee beans and compared light roasting (roasting for 6 minutes, final temperature 147°C), medium roasting (roasting for 11 minutes, final temperature 172°C), and dark roasting (roasting for 18 minutes). , final temperature 191°C), acrylamide content in coffee beans. The results showed that medium-roasted coffee beans had the highest accumulation of acrylamide, while light-roasted and dark-roasted coffee beans had relatively low levels of acrylamide. Many people may be surprised: Why is dark roasting not high in acrylamide? This is because due to the long roasting time of dark roasted coffee beans, asparagine and sucrose are completely consumed, and the melanoidin content gradually increases. The high temperature promotes the nucleophilic addition reaction of acrylamide and melanoidin and the volatilization of acrylamide. reduce its content. 3. Processing methods There are two types of coffee on the market: freshly ground coffee and instant coffee. Freshly ground coffee is coffee obtained by grinding, boiling, and extracting roasted coffee beans. Different coffee production processes will affect its acrylamide content. . Instant coffee is made by roasting, grinding, and extracting coffee beans, then appropriately concentrating them, and then spray-drying or freeze-drying them to obtain instant coffee powder. The aroma and flavor of instant coffee are not as good as freshly ground coffee, and pre-drying, spray drying and other processes will cause part of the acrylamide to volatilize, so the acrylamide content of instant coffee is generally lower than that of freshly ground coffee.
About acrylamide, should we worry about it? When it comes to acrylamide, everyone's first reaction is that it causes cancer, which is why they feel anxious and panicked. In fact, there is no need to worry too much about it. Although a large number of animal in vivo and in vitro experimental studies have shown that acrylamide has obvious mutagenic effects and can cause chromosomal aberrations in rats, leading to tumor growth in multiple tissues and organs such as rat mammary glands, thyroid glands, and adrenal glands.However, there is currently no direct evidence that acrylamide causes cancer in humans. Therefore, acrylamide is classified as a Class 2A carcinogen by the International Agency for Research on Cancer (IARC), which is a substance that is "possibly carcinogenic to humans." For us, Class 2A carcinogens are no strangers and are always around us, such as red meat such as pork, beef, and sheep that many people eat every day. Besides, the potato chips, french fries, toasted steamed bun slices, roasted sweet potatoes, bread, pancakes, fried dumplings, fried dough sticks, etc. that we usually eat all contain acrylamide, and a WHO survey shows that the acrylamide content of potato chips in food is Highest. As potato chips and French fries are fried for longer, the acrylamide content will rise sharply, and is expected to increase by 10 to 20 times. Therefore, for people who only drink one or two cups of coffee a day, there is no need to worry too much about drinking coffee causing cancer. Some substances in coffee can reduce the occurrence of cancer. Coffee contains a series of biologically active chemicals, including diterpene cafestol, polyphenols, caffeine and chlorogenic acid. These substances may affect health and reduce cancer through various mechanisms. occur. One analysis showed a significant inverse relationship between endometrial cancer risk and caffeinated coffee, but not decaffeinated coffee. However, because 3-in-1 coffee contains not only coffee powder, but also creamer, sugar, fat, etc., drinking it regularly will not only make you gain weight, but also increase the risk of cancer. Therefore, it is recommended that friends who like to drink coffee try to drink freshly brewed coffee, and pure instant coffee powder is also acceptable.
How much coffee is appropriate to drink every day? The "Scientific Consensus on Coffee and Health" jointly released by five institutions including the Institute of Nutrition and Health of the Chinese Center for Disease Control and Prevention and the Food Hygiene Branch of the Chinese Society of Preventive Medicine recommends that the daily caffeine intake of ordinary adults should be controlled within 400 mg. Equivalent to no more than 4 cups of pure coffee (150ml/cup). For branded coffee you buy, you can calculate the number of cups by comparing the caffeine content of each cup on the package label; if it is a small bag of 1.8~2g instant coffee, the maximum daily dose is no more than 4 cups. More than 5 bags. In addition, drinking coffee is not recommended for children and adolescents, the elderly, pregnant and lactating people, people with high blood pressure, glaucoma patients, people with a genetic tendency to high intraocular pressure, and patients with osteoporosis. Summary: "Coffee addicts" don't need to panic. It's normal for coffee to contain acrylamide. As long as you don't drink it excessively for a long time, there is no obvious health risk.
Author: Xue Qingxin, member of the Chinese Nutrition Society, registered nutritionist, health manager, public nutritionist Review: Ruan Guangfeng, deputy director of Kexin Food and Health Information Exchange Center
Source/People's Daily Online Popular Science Comprehensive Science China
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