Why the staple grain is potato instead of sweet potato?

At the beginning of 2015, an ordinary piece of agricultural news caused the same sensation as entertainment news. On January 6, the Chinese Academy of Agricultural Sciences, the National Advisory Committee on Food and Nutrition, and the China seed Association held a seminar on the development strategy of potato staple grain in Beijing, focusing on potato staple grain and national food security. the strategic significance, development ideas, objectives, tasks and promotion ways of potato staple grain were discussed in depth. Yu Xinrong, vice minister of agriculture, said at the meeting that we should lead the development of potato as the main grain through scientific and technological innovation, and strive to promote the formation of a new pattern of coordinated development of potatoes and grains. According to reports, potatoes are expected to become the fourth largest staple crop besides rice, wheat and corn. The planting area will gradually expand to 150 million mu, and the annual output of fresh potatoes will increase by 200 million tons, which will significantly improve the national food security level. As soon as the news came out, it immediately aroused the attention of all parties, which made the potato, which has always been neglected, become more popular, but it also caused some debate. Why is it potato, not sweet potato? For example, the title of a report reflects this skepticism: "Mr. Potato withdrew from the vegetable world to become a staple food: sweet potato yam has become dizzy." As an agricultural technician who has studied potatoes for eight years, I am interested and ready to answer this question. Why do potatoes win the competition for new staples?

First of all, from the perspective of the development trend, the potato has been going uphill, while the sweet potato has been going downhill. Compared with sweet potato, after the adjustment in the 1970s and 1980s, the area and yield of potato in China continued to increase, reaching 83 million mu in 2012, with a total output of 18.55 million tons (grain has been discounted at 5:1 and the total output of fresh potato is 92.75 million tons). Accounted for 62% of the national potato area and 56% of the total output. After reaching an all-time high of 150 million mu in 1960, the area of sweet potato has been declining, leaving only about 50 million mu in 2012, nearly 2x3 less than the peak; the yield is 14 million tons (grain has been discounted at 5:1, with a total yield of 70 million tons), nearly 40 per cent less than the peak. It can be said that potatoes and sweet potatoes have completely come out of the different destinies in recent decades. This is obviously a result of natural selection in line with economic laws, and I am afraid that sweet potatoes should have a bit of the spirit of admitting defeat. For example, the dietary status of sweet potatoes has declined significantly. In the past, it was a high-yield crop. It was planted especially in difficult times, and it occupied an important position in dietary consumption for a long time, so that many people had a phobia of sweet potatoes in their stomachs. Nowadays, very few people eat sweet potatoes as a meal. In terms of feed, for example, in the past, the status of sweet potato seedlings should not be underestimated, but now corn plays the main role, and the growth period of sweet potato is basically the same as that of spring corn.

Secondly, from the perspective of the market, potatoes are quite powerful, while sweet potatoes are a little weak. If you use a word to describe the potato market prospects can be described as high-end, atmospheric, high-grade. Potato, corn and wheat are called the three major starch crops. although corn starch has high yield and low price, potato starch can not be replaced by corn starch because of its unique performance, which is mainly manifested in: high viscosity, much higher viscosity than general wheat and corn starch; high degree of polymerization; containing natural phosphate gene; mild taste, basically no irritation, no typical grain taste like wheat and corn. Therefore, although the price of potato starch is higher, it is widely used in food, medicine and other high-end industries, with more than 2000 kinds of derivatives. The value-added space for processing is also amazing, it can be added more than twice as much as ordinary starch, more than ten times as much as special starch, 8 times as much as absorbent resin, 20 times as much as cyclodextrin and more than 60 times as high as biological glue. At the same time, the traditional potato crude starch food processing industry is also undergoing transformation and upgrading, such as the transformation of traditional processing techniques such as vermicelli and vermicelli, which has brought new market space. In particular, potato processed food is still an emerging market with great potential. At present, 70% of the potato processing industry in developed countries is food processing, and China is still in its infancy. What's more, the use of potatoes to develop potato biological batteries is simply unbearable for hold!

Thirdly, from the perspective of adaptation, potatoes can be said to be cosmopolitan, while sweet potatoes are much more delicate. Although both sweet potatoes and sweet potatoes are called potatoes, they are quite different in nature. potatoes are cold crops and do not like the heat. They can sprout above 3 ℃, while sweet potatoes are hot crops and are especially afraid of cold. They can be frozen below 9 ℃. Potatoes are particularly drought-resistant, disaster-resistant and barren-resistant, and generally do not lose the harvest, so they have the nickname "life-saving egg". Mountains, rivers, plains, dams and other topography can be planted, and it doesn't matter if the soil is sour or alkaline. What is even more amazing is that potatoes can be planted in spring, summer, autumn and winter. the fastest seedlings can be harvested in two months and generally in three months, and fresh potatoes can be eaten throughout the country all the year round. A large number of idle rice winter fields in the south have grown a large number of potatoes in recent years, which not only does not affect rice production, but also can rotate stubble, but also increase the harvest of one season. Of course, if you think that the potato yield is low because of the strong resistance of the potato, it will be out. As long as you give the right conditions, the potato yield can exceed your imagination. Scientific research shows that the yield potential of potato is 16 tons per mu. At present, China's fields have created a yield of more than 6 tons per mu, which is enough to make Mr. Yuan Longping's heroic yield level-- more than 30 years of continuous research on hybrid rice. At present, only a small area of 1 ton per mu can be achieved! And delicate sweet potatoes compared to potatoes, it is a bit embarrassing, seedlings have to be in the hotbed, in the past the hotbed filling had to be horse dung, thanks to the change now, otherwise where to find horse dung? After raising seedlings, they have to be transplanted to the field, one by one buried in the soil, and then poured with life-saving water, which is really time-consuming and laborious. Except for the Tropic of Cancer, other places can only be transplanted at this time of the Ching Ming Festival. After the National Day, the harvest is very inflexible. Therefore, "the city is full of potatoes" can be regarded as survival of the fittest.

Fourth, from a nutritional point of view, potatoes are almost divine, while sweet potatoes seem to have a much smaller name. The Solanaceae crops to which potatoes belong can be said to be mankind's closest friends. Tomatoes, eggplants, peppers and potatoes are the four major home vegetables of the Chinese people, and tobacco is the lifeblood of many men. Potato inherits the excellent genes of Solanaceae crops, its nutrition is comprehensive, in addition to carbohydrates, it contains a lot of protein, minerals and vitamins, which is known as "the second bread" abroad; it contains lysine, tryptophan and vitamin C, which are lacking in general food crops, and is also known as "underground apple"; there is also carotene that is not found in wheat and rice. A study in the United States shows that whole milk powder and potatoes can meet the nutritional needs of the human body. Potato is low in fat and calorie, and its carbohydrate content is only 5% of that of rice and noodle; the energy content of potato is less than that of rice and beans; and the fat content of potato is only 1 pound 4 of rice and 8% of flour. Dietary fiber, which is listed as the "seventh nutrient" by nutritionists, is rich in dietary fiber, which can reduce the incidence of chronic constipation and reduce the levels of blood lipids, blood sugar and cholesterol in the body. Scientists have also shown that potatoes are the food of the future. at present, astronauts' space food includes potatoes, and potatoes are the most ideal crop on the way to other planets in the future. What about the nutrition of sweet potatoes? Similar to potatoes, because they grow underground, they are also rich in vitamins and dietary fiber, but are high in starch and sugar.

Fifth, from the current dietary status, potatoes belong to the poor and the rich, while sweet potatoes are more like those of the poor. The edible value of potatoes was discovered by the hungry poor in brave attempts, because they found that when the pigsty pigs snuffed out some magical lumps from the ground and ate them safe and sound, the poor no longer hesitated. The changing world potato pattern in recent years shows that the area and output of Asia and Africa are increasing year by year, and potatoes continue to provide food and economic income support for people in developing countries. Potatoes belong to the poor. But looking at the world distribution of the potato industry, we can also be surprised to find that the potato industry is mainly distributed in the northern hemisphere of the world, and Europe and North America, the most developed regions in the world, are also the most concentrated areas of potato cultivation; potatoes were originally the favorite of the aristocracy, even today, McDonald's French fries are to some extent a symbol of American culture, in this sense, potatoes belong to the rich. Therefore, the world eats potatoes, and the potato industry has spring. At present, the per capita annual consumption of European countries is stable at 50-60 kg, while the per capita consumption of Russia is more than 170 kg, while that of China is only about 30 kg, which really has room for growth. Due to growth habits, sweet potatoes are mainly planted in the south of latitude 40 °N. Asia, dominated by China, accounts for 80% of the world's output, which cannot be called the world's staple food.

Of course, having said so much, the introduction of potatoes into staple grains is not a matter of instant entry. People must be willing to eat as staple grains, which requires some changes in concept. For a long time, when it comes to potatoes, people's first impression is that they have a high starch content and it is easy to get fat if they eat more. This is actually a serious misunderstanding. Generally speaking, the starch content of potatoes is only 15%, 18%, which is much less than that of rice noodles. In production, starch processing plants have long urged scientists to develop potatoes with higher starch content, but the results are not satisfactory. Not only that, potatoes also suffer from cultural injustice. For example, Marx once used a sack of potatoes to describe French farmers in the 19th century. There is a saying in the northeast that "potatoes are still potatoes". For example, if you eat a baked or steamed potato every morning, the Russians may be used to it, but the Chinese will not be able to stand it for a while. In order to get potatoes into the staple food, it is necessary to go to rustic and prejudice, which requires long-term propaganda and guidance.

And there are technical problems. For example, for more people, potatoes are more like vegetables. Changing from vegetables to grain requires good recipes. Potatoes with low starch and protein content cannot make noodles and can only be mixed with flour to make flour products. It is destined that potatoes will be mixed as staple food in the future rather than alone. The development variety of potato staple food products is still very monotonous and poor selectivity, such as potato fast food, mashed potato, potato bread, potato instant noodles, potato chips, preserved potato, potato beverage and other foreign mature products are still rare in China, especially in the United States and Japan, frozen products which account for more than 50% of the market for potato products and more than 10% of mixed food are still quite new in China. Potato products such as deep-fried French fries and potato chips increase the intake of oil and salt, which is not conducive to health. It is a junk food that nutritionists try their best to prevent, and there are doubts about carcinogens caused by frying denaturation.

In the future, if we want to expand the planting area in accordance with local conditions, expand it to 150 million mu without squeezing out the three staple grains, increase the yield of potatoes per mu to 2 tons, and the annual output of fresh potatoes to about 300 million tons, we even need market benefits to guide farmers to be willing to grow. We also need to make more efforts in scientific research and popularization, so as to combine excellent varieties with scientific agronomy to increase production and income.

But in any case, from the day it is announced that potatoes will enter the staple grain, the rice bowls of the Chinese people will begin a revolutionary change, which is not only related to everyone's dietary structure and nutritional health, but also to the adjustment of the country's food strategy. it will also bring about a profound evolution of food culture, which is worth looking forward to!