Purple potatoes have entered our lives for a long time, from a rarity to a daily food. There are often sweet potato puree in the restaurant. Steamed purple potatoes are often sold in the dining hall. There are also purple potato moon cakes, purple potato dumplings, and purple potato cakes. However, the various problems related to purple potato still plague many people.
Question 1: Online flow legend, the purple color of purple potato is genetically modified, and can not be eaten? What is the purple color of purple potato?
Many people may not know that purple potato is actually a kind of sweet potato that is eaten daily, and sweet potato and sweet potato are a kind of plant, but only the purple variety. Sweet potato (Latin species) belongs to the dicotyledonous plant of the genus Convolvulaceae. The purple sweet potato is widely planted in Guangdong, Hunan, Shandong and other places in China. It is a short-day crop that enjoys warm climate.
Compared with the sweet potato that we often eat, the purple potato has a darker skin and a purple root. Because I have never seen this variety before, many people have a doubt: Is the purple color of purple potato obtained from genetic modification?
A transgene is a target gene that has been artificially isolated and modified and introduced into the genome of another organism by biotechnology, that is, the species A exhibits a certain trait of the species B. For example, let rice seeds grow into yellow of certain flower plants (to produce carotene). The development process of genetically modified foods is complicated and costly. It is not a cost-effective sale for purple potatoes with lower prices and lower yields. Besides, purple sweet potato varieties have existed since ancient times, why bother to do what genetics?
(Here a few more words here: the richness of plant species in nature far exceeds our imagination. For example, purple sweet potatoes, purple potatoes, purple carrots, green rice, black wheat grains… all exist from ancient times. They have not seen them before, but because the output is too small, there is no large-scale commercial development. We are not experts in agricultural varieties. It is normal to see them. It is not necessary to imagine the varieties that have never been seen as genetically modified. )
Question 2: Is the purple potato I bought dyed? Why is it so easy to change color?
Indeed, purple potato is simply a chameleon. If you cook it, the purple will dissolve into the water and it will easily turn green. If you put the purple potato and egg white together, you will find that the egg white color changes from white to green. If you mix the purple potato puree with the flour and add a small amount of baking soda to make the cake, the color will turn blue-violet. Many people think that the discoloration ability of purple potato is a bit scary.
The so-called dyeing is to add a coloring agent to the food processing to make the food appear in various colors. The basic requirements of synthetic food colorants, in addition to the toxicity is small enough, is that the color is stable and does not change color. The pigment in purple potato is so discolored, so this one is not in contact with synthetic pigments.
So where is the purple color of purple potato coming from there? What is it?
The answer is anthocyanins. Anthocyanidins are a class of water-soluble natural pigments widely found in natural plants [2]. The anthocyanins in plants are very unstable. They are afraid of heat and are afraid of light, and they are afraid of oxidation. In foods, they often combine with one or a half of galactose, rhamnose or glucose to form anthocyanins, which greatly increase light fastness and heat resistance. Even so, when the pH changes, they will still have obvious discoloration, such as reddening, turning blue, turning green, etc., which are the natural characteristics of anthocyanins.
There are many varieties of purple sweet potato, and the anthocyanin composition of different varieties is different, but the main components are cyanidin and peony, both of which have the acyl group of ferulic acid, caffeic acid or p-hydroxybenzoic acid, and both 3,5-diglucoside significantly improved the stability of purple potato anthocyanins. Therefore, even if the purple potato is cooked, most of the anthocyanins can be retained.
Question 3: I heard that anthocyanins have many benefits? Does the anthocyanin of purple potato have many health functions like blueberries?
Indeed, scientists have done a lot of research on anthocyanins in purple potatoes. Let’s sort out the main results of the following aspects –
It is known that anthocyanins have a strong antioxidant effect. Japanese scholars compared the free radical scavenging effects of different flesh-colored sweet potatoes. It was found that purple potato had the strongest ability compared with sweet potato of white, yellow and orange flesh, and the main component of free radical scavenging effect was anthocyanin. Comparing a variety of common antioxidants, it was found that the antioxidant capacity of purple potato anthocyanins is stronger than chlorogenic acid (which is an important health component in fruits such as apples) and vitamin C. Kano et al. [7] did a human experiment, and after volunteers drink purple potato juice, the urine test results show that the DPPH free radical scavenging effect is enhanced, which proves that purple potato does have the effect of scavenging free radicals in the human body.
Studies have found that purple potato anthocyanins can change the microbial composition in the large intestine, significantly increasing the “good bacteria” such as bifidobacteria, lactobacilli and enterococci in the intestine. Researchers believe that eating purple-rich anthocyanins may be beneficial to the intestinal microbial environment and human health.
The study found that the mice’s intake of purple potato extract containing anthocyanins increased spatial learning ability and memory ability. Proteomic analysis of the mouse brain revealed a significant increase in protein content associated with antioxidants, energy metabolism, and neural plasticity.
When it comes to anthocyanins that have a protective effect on vision, it is easy to think of “blueberries.” Since purple potato is also rich in anthocyanins, does it have a similar effect? Purple potato anthocyanins promote the growth of retinal pigment epithelial cells, suggesting that it may also have a potential role in protecting vision.
Studies have shown that the antioxidant effects of anthocyanins contained in blueberries and purple potatoes are not much different, and they also have the effect of protecting eyesight. Then, from the purple potato to eat anthocyanins, or from the blueberries to eat anthocyanins, which one is more Is it cost effective? I know it when I count it.
Question 4: Blueberries, black mites, and purple potatoes all contain anthocyanins. Which one is more cost-effective to eat?
The anthocyanin content of blueberry is 1.29mg/g, while the purple potato is only 0.51mg/g. It is true that the blueberry is leading a lot in the content, but after the discounted price, the price of anthocyanin in blueberry is 110 yuan/ g, while purple potato is only 20 yuan / g. In recent years, the products such as black scorpion that has been hot-fried, although the anthocyanin content is far ahead of blueberries, the health effect is indeed good, but the price is even higher, and the price is higher according to the anthocyanin price. Therefore, for those who pursue cost-effectiveness, purple potato is a very good daily choice.
Of course, every food has its own nutritional balance and health functions, but how much it can be eaten is a very important thing. The best food, because it is especially expensive, is eaten several times a year, and the effect is very limited. For ordinary wage earners, if you can’t afford those high-quality foods, you can eat regular and long-term foods that contain nutritious and healthy ingredients. For many years, the effect may be even bigger.
Question 5: Does purple potato contain so much starch that it can be eaten as a staple food? What proportion of steamed purple potato and rice steamed bread is replaced?
Indeed, purple potatoes contain quite a lot of starch, and eating it will reduce other staple foods.
Rice is good, and steamed bread is also a staple food made from cereals (food). Whether it is rice or noodles, it is millet or corn, the common feature of cereals is that they contain very high starch, which can reach 70%-80%, and the heat contained in 100g is between 340-380 kcal. Don’t be scared because of the high heat – because they are doing it.
In contrast, the starch content of purple potato is not so high, and the purple potato variety that tastes “very good” has only 23% starch. Therefore, compared with food, the starch content of purple potato is not too high, probably less than one-third of the rice white noodles. Therefore, if you replace 1 two meters with 3 two purple potatoes, the heat is slightly lower than 1 two meters.
However, many friends said that I did not eat raw rice, tell me directly how much rice can be changed! According to the calculation of northeast rice, 1 kg of raw rice can steam 2.3 kg of rice. The starch content of cooked rice is about 34%, the starch content of taro is 47%, and the starch content of purple potato is basically unchanged after steaming. Therefore, in terms of providing the same starch, 300 grams of purple potato is roughly equivalent to 200 grams of cooked rice (shallow bowl), and 200 grams of purple potato is equivalent to 100 grams of steamed bread. In short, if we eat a few mouthfuls of rice and replace it with a few mouthfuls of purple potatoes, it will not gain weight.
Question 6: I want to lose weight, eat purple potato instead of a part of rice as a staple food? Can you help slim down?
From the perspective of providing heat, the heat of cooked purple potato (about 100 kcal/100g) is slightly lower than the heat supplied by rice (about 116kcal/100g), which is much lower than the heat (220kcal/100g) contained in the weight of steamed bread. However, purple potato is more “squatting”, so using purple potato as a staple food, it is not easy to eat too much starch, because after eating a certain amount, I feel full.
In addition, people tend to eat more when the food is delicious, but the purple potato with the dishes is not as perfect as the white rice garnish, so it is not easy to eat a piece of purple potato because the dishes are delicious.
In terms of digestion rate, the amylose content of purple sweet potato (about 18% dry weight) (Shan Shan et al., 2011) is higher than that of northeast rice (about 15%), and the amylose digestion rate is slower than that of amylopectin. The dietary fiber in potato is rich, which can delay the emptying speed of the stomach. The large amount of polyphenols contained in the potato also has the effect of reducing the activity of digestive enzymes. Therefore, in theory, purple potato is slower than rice and can be better. Maintaining a sense of satiety, especially for people who are in the process of losing weight, using purple sweet potato with rice as a staple food should be beneficial for weight control and postprandial blood glucose. How strong the specific effect is, and research and verification are needed.
Question 7: My relatives have constipation problems, the large intestine and precancerous lesions. The doctor suggested that he often eat sweet potatoes, because sweet potatoes are especially beneficial to the large intestines. Can he eat purple potatoes?
The dietary fiber content in the traditional staple food is low, the dietary fiber content in rice is about 0.007g/dry weight, the steamed bread is about 0.020g/dry weight, and the dietary fiber content of purple sweet potato is as high as 0.030g/dry weight (Huang Wei, etc.) , 2011). Partial replacement of white rice with white sweet potato as a staple food can increase the intake of dietary fiber, which is similar to sweet potato.
Studies have also shown that purple potato anthocyanins can significantly increase the content of bifidobacteria, lactic acid bacteria and enterococci in vitro experiments. It is speculated that the consumption of anthocyanin-rich purple potatoes has beneficial effects on intestinal microenvironment and human health (Zhang X et Al, 2016), then it is good for the prevention of bowel cancer. As to whether the effect of sweet potato on preventing constipation is so good, research data is needed to verify. But at least one thing is certain, people with constipation can eat purple potatoes.
Question 8: Both said that potatoes are rich in potassium and vitamin C. Does purple potato have these nutrients?
Yes. All potatoes, including potatoes, sweet potatoes, yam, and taro, contain a lot of potassium and vitamin C. The dietary fiber content is very high, and the strontium content is very low. The same is true for purple potatoes. This characteristic of potato is a great advantage for patients with high blood pressure, gout and other diseases. Using them to replace a part of white rice white noodles is conducive to the prevention and control of a variety of chronic diseases.
Question 9: How many potatoes do you eat every day? Which sweet potato and purple potato should I choose?
In the 2016 version of the Chinese Dietary Guidelines, 250-400g of cereals are recommended for daily consumption, including 50-150g of whole grains and miscellaneous beans, and 50-100g of potatoes. The so-called 50-100g of potato is consumed daily, including purple sweet potato. However, there is no need to eat purple potato, a type of potato, every day, and you can exchange it with sweet potatoes, yam, taro, potatoes and other potatoes.
On the one hand, if your stomach and tongue like which kind of potato, eat more. Some people eat the sweet potato stomach is not comfortable, eat yam and potatoes are comfortable, then temporarily eat yam, potatoes and not eat purple potatoes. Some people eat purple potatoes feel very happy, then you can increase the proportion of purple potatoes in the limit of eating potatoes every day.
On the other hand, if you have any ingredients in your diet, choose different potatoes. For example, sweet potato can provide carotene, which can be converted into vitamin A in the body; while purple potato carotene content is very low, people who lack vitamin A eat sweet potato supplement vitamin A is better. Conversely, if people with high blood pressure and high blood lipids have serious oxidative stress in their bodies, the antioxidant effect of eating purple potato is stronger than eating sweet potatoes and potatoes. You can change some sweet potatoes and potatoes into purple potatoes. .
Question 10: When I eat purple potato, my stomach is blocked. Is it completely impossible to eat?
Purple potato is not easy to digest. Purple sweet potato itself is relatively close in texture, and the rich polyphenols contained in it also have the effect of delaying digestion. People with too little stomach acid and insufficient gastric motility should not eat a lot of purple sweet potato, otherwise it may cause discomfort. Wait until the digestive power is slowly increasing, and it is ok to try it again.
In general, for the same plant seed or plant tubers, dark varieties tend to be more difficult to digest than lighter varieties, such as black, purple and red varieties, which are more difficult to digest than yellow and white varieties. If your stomach is not good, don’t eat too much, and don’t eat purple potatoes on an empty stomach. It is possible to consider preferential consumption of yam, taro and other relatively easy to digest potatoes.
When eating purple sweet potato, it is recommended to steam it until it is fully soft and then eaten. The quantity is also very important, don’t eat too much at once. If you mix it in other foods, such as purple potato yam, purple potato porridge, purple potato cake, etc., it is not easy to appear uncomfortable. You can occasionally mix a small amount of purple potato and rice together, or eat rice, taro, porridge and other foods first, then eat a small amount of purple potato, it will feel much better.
In short, purple potato is just a potato, a sister of sweet potatoes. Its purple color is neither genetically modified nor stained, but derived from naturally occurring anthocyanins. Everyone can enjoy it deliciously, just remember that if you want to eat purple sweet potato, the rice steamed bread will be reduced accordingly.
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