Old women should Changshi seaw
Students should eat more food
On the quality of vegetables and Health 
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people buy vegetables, often only pay attention to the shape of vegetables, fresh, taste, color, fragrance endures in the quality of vegetables have been ignored in the nutritional quality and health quality. With the improvement of living standards, people's quality of the vegetables are getting higher and higher. The nutritional quality of vegetables and the quality of health and the health of the relationship between people's growing attention. Now older and friends to talk about this issue.
the nutritional quality of vegetables include: protein, minerals, vitamins, aromatic substances, low-calorie, as well as crude fiber, and so on. The higher the concentration of these substances, the nutritional value of vegetables have to be increased. In addition, the moisture and cellulose content of vegetables are also important indicators of the quality of nutrition. Typically, the high water content, fresh vegetable cellulose less good degree, the higher the value of food. But from the point of view of health care, dietary fiber is a necessary nutrient. Old friends usually eat more cabbage, celery, and so on a class of cellulose-rich vegetables to prevent constipation and a lot of good.
a variety of vegetables have nutritive value certain. Comprehensive comparison of the various nutrients vegetables, vegetables could be more or less classified into three categories: (1) high nutrient vegetables are: vegetable soybean, green peas, green beans, cabbage, Mustard, spinach, kale and garlic, etc. ; (2) nutrient composition of the middle of the main vegetables: beans, cowpea, leeks, cabbage, lettuce, green onions, broccoli, carrot, radish, potato, onion, towel gourd, sweet pepper and hot pepper, and so on; (3) nutrients lower There are vegetables: cabbage, pumpkin, squash, wax gourd, eggplant and tomato and so on.
vegetable also known as the quality of health safety quality, the main means of chemical pollution and biological contamination. In the growth of vegetables, the use of a large number of human waste, the health quality of vegetables is biological pollution, such as bacteria, parasite eggs, and so on; in the use of chemical fertilizers, pesticides and irrigation water, vegetables, the quality of health is the main nitrate accumulation, Concentration of heavy metals and pesticide residues, and so on, all countries have the appropriate standards or targets.
in the light of the World Health Organization and UN Food and Agriculture Organization of the day to allow the provisions of nitrate intake, the estimated China Nitrate vegetables to allow for the amount of 432 mg / kg fresh weight. If you take into account the salinization and the loss of cooking time (to 45% and 70% of the total), this limit could be expanded to 785 mg / kg and 1440 mg / kg. This made China's vegetable nitrate pollution and health evaluation criteria:
nitrate content (mg / kg fresh weight) greater than or equal to 432 hours for light pollution to allow raw food; greater than or equal to 785 hours for the moderate pollution, not raw, but allow saline, cooked food; greater than or Equal to 1440 for a high degree of pollution, not raw, salted, but allow the cooked food; greater than or equal to 3100 for serious pollution, does not allow for human consumption.
human intake of about 80% of nitrate from vegetables, vegetable nitrate content in the level of human health and a very close relationship. Therefore, the nitrate content of vegetables is an important indicator of quality, and there has been widespread concern. Vegetables generally contain a certain number of parts of the nitrate. Nitrate reduction in the conditions of the formation of nitrite, and nitrite-combine to form nitrosamines, the cancer is more of a class of organic compounds. Its time to induce cancer with the increase in daily intake and shortening, so consumption of high nitrate content of vegetables on human health hazards great.
accordance with the determination, part of the consumption of vegetables as a result of the nitrate content type to another, and different types of the same species, with different parts of a vegetable or a different harvest time have a greater difference. The Mustard nitrate content of the highest, lowest round eggplants and carrots, 90 times the difference between the two. Different types of vegetables nitrate content distribution are: leafy than Gencai Lei, Gen Cailei than Congsuan category, type of fruit than Congsuan category, type of fruit than beans, legumes than Jiaguo Category.
vegetables harvested in accordance with the part of the potential nitrate accumulation capacity of vegetables can be divided into three groups: (1) the cumulative volume Nitrate vegetables: lettuce, spinach, cabbage, radish and red beet, and so on; (2) nitrate Medium accumulation of vegetables: celery, carrots, cauliflower, potatoes and leeks, and so on; (3) the cumulative amount of low-nitrate vegetables: tomato, cucumber, sweet pepper, peas and beans, and so on.
the above information will not only increase people's understanding of the quality of vegetables, health, but also for the elderly to buy friends and vegetable consumption has some reference value.
At present, high levels of nitrate in vegetables was mainly attributable to: (1) excessive use of nitrogen fertilizer. (2) the long-N, N, P and K nutrient imbalance. (3) unreasonable harvest time. As the Absorption vegetables into the nitrogen needs a process. If top-dressing, eager to harvest water after the listing, the accumulated nitrate in vegetables too, will inevitably affect the quality of health. According to the study, nitrogen topdressing after 8 days for the vegetable market of rhythm.
there are a few suggestions for the final Old friends reference. (1) to improve eating habits. Eat more fruits and vegetables (such as melons, beans, Jiaguo Lei), eat root vegetables, leafy vegetables; eat more fresh vegetables, eat pickled vegetables; ready food to eat more, eat less lettuce, reducing the potential hazards of nitrate to a certain extent Benefits. (2) to buy vegetables, leafy vegetables in addition to individual species due to the characteristics of deep color, leaf color is best not to buy vegetables too, such as vegetables may have too much nitrogen fertilizer, excessive nitrates in the body. (3) to buy tomatoes, pay attention to the selection of sleek shape, full of flesh, and the election will not have a green back, there are fruit-shaped or angular deformity of the tomato. This is because the pointed shape like the peach tomato is the use of excessive hormone produced deformed fruit. Green fruit and fruit-back phenomenon has edges and corners (hollow, not full) are typical symptoms of potassium deficiency, poor nutritional value. (4) eat leeks. Since the Chive is a perennial vegetable, a large number of commonly used pesticides to kill maggots, the leeks in a higher amount of pesticide residues. In addition, Chinese chives are the properties of mercury concentration of heavy metals. Of course, occasionally eat a leek dumpling stuffing do not have to worry too much about it.
