Interviewed experts: Chinese Nutrition Society, Shandong University nutrition and Food Hygiene Institute Professor Lin Xinying
Recently, online crazy pass such a message, China's potatoes after cutting black, is genetically modified potatoes! And American potatoes cut black." Is this really the case?
Chinese nutrition society director, Shandong University nutrition and Food Hygiene Institute Professor Lin Xinying pointed out that this argument has no scientific basis. Cut the potatoes will be black, because potatoes contain phenolic chemicals and polyphenol oxidase in the open process of chemistry of phenolic compounds containing out of contact with the outside world in oxygen, polyphenol oxidase catalyzed the formation of ortho - quinone compound unstable, then mutual polymerization or function and protein, amino acid the formation of the polymer complex and make the potato cutting surface browning (placing a long time on the black). Chinese people to eat potatoes mainly fried potato silk, generally now do is eat, placed not long time after cutting, and will rinse water, which slows down the browning speed to a great extent, is also mentioned in the message "Chinese in front of potatoes cut, but with the same black" GM is not necessarily linked.
The effect of potato browning degree and polyphenol oxidase activity among different varieties, some varieties of cut color quickly because of its strong polyphenol oxidase activity; some varieties of polyphenol oxidase activity is relatively low, so take a long time to change. Potato browning degree is also related to its environmental conditions, such as temperature, humidity, pH, etc.." Lin Xinying explained. At present, all potato varieties in China contain phenolic compounds, but also contains polyphenol oxidase, but the degree of discoloration and time difference. More importantly, our country did not approve the cultivation of transgenic anti enzymatic browning potato varieties, and the market has not heard of potatoes after the sale does not change color.
In addition, potatoes unchanged black and nutrition is not directly related. In order to prevent the browning of sensory effects, potatoes can be used to cut open, immersed in water, rinse with hot water, vitamin C and citric acid solution and vacuum packaging method in a certain extent after cutting the browning control of potatoes.