Researchers in Europe and the United States found that when certain foods heated to a temperature above 120 degrees Celsius (248 degrees Fahrenheit), a chemical substance called acrylamide produced. Moreover, the level of it appears to increase with the duration of heating. The highest levels found so far were in starchy foods (potato and cereal products such as potato chips and French fries). And this is not found when foods prepared below this temperature.
The reason for this might be due to asparagine (a kind of amino acid) which is found in many vegetables, with higher concentrations in some varieties of potatoes. When heated to high temperatures in the presence of certain sugars (reducing sugars such as fructose and glucose), asparagine can form acrylamide, especially when we use such cooking methods as frying, baking or broiling, while boiling and microwaving appear less likely to have such effect. Longer cooking times can also increase acrylamide production when the cooking temperature is above 120 degrees Celsius.
Decreasing cooking time, blanching potatoes before frying and postdrying (drying in a hot air oven after frying) have been shown to decrease the acrylamide content of some foods.
The reason for this might be due to asparagine (a kind of amino acid) which is found in many vegetables, with higher concentrations in some varieties of potatoes. When heated to high temperatures in the presence of certain sugars (reducing sugars such as fructose and glucose), asparagine can form acrylamide, especially when we use such cooking methods as frying, baking or broiling, while boiling and microwaving appear less likely to have such effect. Longer cooking times can also increase acrylamide production when the cooking temperature is above 120 degrees Celsius.
Decreasing cooking time, blanching potatoes before frying and postdrying (drying in a hot air oven after frying) have been shown to decrease the acrylamide content of some foods.
Acrylamide has so far not been found in food prepared at temperatures below 120 degrees Celsius, including boiled foods. Thus foods should not be cooked excessively, i.e. for too long or at too high a temperature.
Acrylamide is known to cause cancer in animals. Besides, it has toxic effects on the nervous system and on fertility. But a June 2002 report by the Food and Agriculture Organization of the United Nations and the World Health Organization concluded the intake level required to observe neuropathy (0.5 mg/kg body weight/day) was 500 times higher than the average dietary intake of acrylamide (1 μg/kg body weight/day). In our daily diet, for example, zucchini produces only 360 micrograms per kilogram of acrylamide, garlic 200 micrograms while cabbage and Chinese lettuce less than 50 micrograms.
For effects on fertility, the level is 2,000 times higher than the average intake. From this, they concluded acrylamide levels in food were safe in terms of neuropathy, but raised concerns over human carcinogenicity based on known carcinogenicity in laboratory animals.
Thus whenever possible, we should eat foods raw. But in this case, we should be careful about the harmful effect caused by bacteria inside all foods when they have not been cooked sufficiently.
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