We all know that there are more than 40 kinds of essential nutrients for human body, which can be divided into carbohydrates, fats, protein, inorganic salts, vitamins and water according to their chemical composition and physiological functions. The main nutrients in human body are protein, fat and carbohydrate. Rice is an indispensable food in the diet of China people. As one of the staple foods, you should eat it every day. With the continuous improvement of people's living standards, especially people's demand for staple rice has gradually shifted from solving food and clothing to the characteristics of good taste, nutrition, safety and dietotherapy.
Today, Bian Xiao brings you some characteristics of rice for main analysis:
First, the nutritional value of rice
Rice not only contains a lot of protein, fat, carbohydrate and cellulose, but also contains various minerals and vitamins needed by human body.
Protein: Although the content of protein in rice is not high, only 8%- 10%, compared with other cereal protein, the amino acid composition of rice protein is more reasonable, easy to digest and less allergic, so it is often used as the raw material of baby food.
Lipids: The lipids in rice are distributed in aleurone layer and germ, mainly triglycerides, and a small amount of phytosterol and lecithin. Aleurone layer and germ are ground off during rice processing, so the lipid content of rice is very low, about 1-2%.
Carbohydrate: The carbohydrate of rice is concentrated in the endosperm, with an average of about 70%, mainly starch, accounting for 90%, and the rest 10% is dextrin, fructose and dietary fiber. Rice is the most ideal and economical heat energy source for human beings, accounting for 60-70% of the heat energy source for human beings.
Minerals: Rice is rich in minerals, mainly calcium, iron, zinc, magnesium, copper and molybdenum. It mainly exists in aleurone layer and cortex, and it is easy to be lost during processing. So we don't advocate over-processing and eating high-precision rice.
Vitamins: Rice contains a variety of B vitamins, mainly distributed in aleurone layer and germ, and the processing accuracy directly affects its content.
Second, the classification and grading of rice varieties
There are many ways to classify rice. According to China's current national standard "Rice" (GBL 354-2009), it is divided into three categories:
(1) indica rice
Rice made from waxy indica rice. Rice grains are generally rectangular or slender. According to its grain quality and indica rice harvest season, it can be divided into the following two types:
Early indica rice: white belly and less hard grains.
Late indica rice: smaller belly white and harder grains.
(2) Japonica rice
Rice made from Japanese non-glutinous rice. Rice grains are generally oval. According to its grain quality and japonica rice harvest season, it can be divided into the following two types:
Early japonica rice: white belly and few hard grains.
Late japonica rice: the belly is smaller and the grains are harder.
(3) Glutinous rice
Rice made of glutinous rice. According to its particle shape, it can be divided into the following two types:
Indica rice and glutinous rice: rice made of indica rice and glutinous rice. Rice grains are generally rectangular or slender, milky white and opaque; Some are translucent (commonly known as Yinnuo) and sticky.
Japonica glutinous rice: Rice made of japonica glutinous rice. Rice grains are generally oval, milky white and opaque; There is also translucent (commonly known as Yinnuo), which is sticky.
The quality of rice in China is determined by the processing accuracy, broken rice and the maximum limit of small broken rice, imperfect grains and impurities. According to the national standard "Rice" (GB l354―2009), rice is divided into four grades according to its processing accuracy and other indicators.
Rice is one of the staple foods of human beings, but food safety incidents such as the cadmium rice incident in Hunan, the genetically modified rice incident in Wuhan, and the renovation of old grain by illegal manufacturers have occurred one after another. It's not easy to eat a bowl of rice.
According to the evaluation of 4 1 index of 7 kinds of rice products by experts in Beijing, only 9 kinds of rice products meet the evaluation criteria, and the qualified rate is 52.9%, which is far lower than the overall average qualified rate of 70% of food.
Let's take a look at the relevant test data report:
The qualified products in this sampling inspection are Xiaoxiang Rice (5kg) in He Miao, Nuo Min, Pearl Rice (5kg) in Beidahuang, Daohuaxiang Rice (Wuchang Rice) (2.5kg) in Longfuyuan, Long Grain Japonica Rice (5kg) in Qiheyuan, Snow City Rice (5kg) in Dahe, Long Grain Aromatic Rice (5kg) in Beidahuang and Fresh Aromatic Rice (5kg) in Beidahuang. (Note: This report is only responsible for sampling samples, and does not mean that other untested products are unqualified. )
I. Product evaluation
All evaluation products are pre-packaged products. Rice varieties are northeast japonica rice, including long grain rice, medium grain rice and pearl rice. Of the 17 batches of rice products evaluated, 9 batches were qualified, and * * * involved 16 batches. There are 1 1 supermarkets sampling qualified products: Carrefour Guangqumen Store, Carrefour Beijing Fiona Fang Store, Carrefour Jianxiangqiao Store in Beijing, Carrefour Dazhongsi Store in Beijing, Carrefour Wangjing Store in Beijing, Carrefour Chuangyi Store in Beijing, Asian Games Village Store in Huatang Shopping Mall, Youanmen Store in Huatang Shopping Mall, Yonghui Supermarket Chain Store in Beijing Qi Long Store, RT Mart Minzu Garden Road Store in Beijing, and Tiankelong Intersection in Beijing.
Second, the evaluation criteria
Food safety is a global problem, and all countries, the World Health Organization and the European Union have their own food safety standards. This evaluation is not a single reference to the food safety standards of China or a country or organization, but the unification of national standards and international standards based on European standards. Simply put, the stricter one of the national standard and the European standard is adopted as the evaluation standard.
For example, the limit standard of heavy metal mercury in rice is stipulated in GB 2762 as 0.02 mg/kg, but it is not clearly stipulated in European standard (EC)No. 188 1/2006. The total mercury is evaluated as 0.02mg/kg as stipulated in the national standard. Transgenic rice has not been approved for commercial cultivation in China, so it is not allowed to appear in the circulation field. However, the regulation of European Union (EC)No. 1829/2003 on genetically modified rice requires clear identification, so it is not allowed to use the provisions in the national standard to detect genetically modified rice.
Third, the evaluation project
The evaluation project considers the production process of rice, including rice seed selection, planting, harvesting, storage, rice screening, impurity removal (such as stones and other impurities) and hulling (rice husk, dust, sand and gravel removal). ), rice milling (removing the brown husk outside the grain to obtain white rice) and polishing (further grinding the white rice obtained by rice milling to remove more). Including transgenic, heavy metals, pesticide residues, mycotoxins, sulfur dioxide * * * 4 1.
1 transgenic
At present, the main purpose of transgenic rice is to improve the level of crop protection, achieve pest resistance and increase rice yield by enhancing the resistance to plant diseases caused by insects or viruses or enhancing the tolerance to herbicides.
At present, quasi-genetically modified food has not been approved for commercial cultivation in China, and the harm of genetically modified food to human health is not very clear, so it is not recommended to eat genetically modified food for a long time.
Five heavy metals: lead, arsenic, mercury, chromium and cadmium.
The land and water sources where rice is planted are polluted, and the content of toxic and harmful heavy metals may exceed the standard, which will be absorbed by crops and accumulated in rice.
Lead poisoning can lead to abdominal pain, diarrhea, vomiting, headache, dizziness, insomnia, and even coma, palpitation, anemia, vasospasm, liver and kidney damage. It will seriously affect the growth and development of children.
Arsenic poisoning can damage human nervous system, cause gastrointestinal dysfunction and liver diseases.
Mercury poisoning will have a serious impact on the nerves and brain.
Chromium (mainly hexavalent chromium) is very toxic, which can lead to chronic poisoning, liver and kidney damage, nausea, gastrointestinal irritation, gastric ulcer, spasm and even death.
Excessive intake of cadmium mainly causes kidney damage, and extremely serious advanced patients may have bone lesions.
3 30 pesticide residues
In the process of rice planting, excessive spraying of pesticides or not spraying pesticides according to the provisions of the withdrawal period will cause a large accumulation of pesticides in rice.
Long-term intake of food with high pesticide residues will lead to chronic poisoning, which may induce gene mutation, increase the proportion and possibility of carcinogenesis and teratogenesis, and seriously affect the enzyme and reproductive system in human body, especially the male reproductive system.
Four mycotoxins (aflatoxin B 1, zearalenone, deoxynivalenol, ochratoxin A)
After rice is harvested and processed, due to poor storage conditions, improper temperature and humidity control, poor packaging isolation and other reasons, mildew may occur in the circulation and storage process and produce toxins.
Fungi and their toxins are closely related to the occurrence of human cancer. Aflatoxin B 1 is the most carcinogenic chemical, which can cause cancer, acute poisoning and serious death.
5 sulfur dioxide
It is forbidden to use sulfur dioxide in rice processing and production. Some unscrupulous manufacturers bleach old rice or moldy rice with sodium metabisulfite, and then polish it as new rice, so that sulfur dioxide or sodium metabisulfite will remain in the rice.
Excessive intake of sulfur dioxide through the mouth, its toxicity is manifested as gastrointestinal reactions such as nausea and vomiting. In addition, it can affect the absorption of calcium and promote the loss of calcium.
Fourthly, analysis of evaluation results.
7 kinds of products were sampled in supermarket circulation channels, and the results showed that only 9 *** 16 batches of rice met the evaluation criteria. The qualified products are Xiaoxiang Rice (5kg) in He Miao, Nuo Min, Pearl Rice (5kg) in Beidahuang, Daohuaxiang Rice (Wuchang Rice) (2.5kg) in Longfuyuan, Long Grain Japonica Rice (5kg) in Qiheyuan, Snow City Rice in Dahe (5kg), Long Grain Fragrant Rice in Beidahuang (5kg), Fresh Fragrant Rice in Beidahuang and Meilin. See the following table for the information of the sampled products: According to the test results, the nine products that meet the evaluation criteria are all rice from northeast producing areas, and no mycotoxins, pesticide residues, sulfur dioxide, etc. were detected, especially two kinds of rice, pearl rice (5kg) in Beidahuang and long-grain japonica rice (5 kg) in Qiheyuan, which were evaluated in four batches, reflecting that the qualified products were well controlled in rice planting, processing, storage and circulation.
Only heavy metals were detected, and the difference between products was very small, and the detection value met the evaluation standard. In a safe range, long-term consumption of qualified products of this detection level will not have a significant impact on human health. The source of heavy metals in rice is closely related to the ecological environment such as soil, water and air, and comes from the pollution brought by industry, agriculture and life. The experimental results show that the ecological environment in the northeast producing area is good and suitable for planting crop rice.
The consistently detected items are heavy metal arsenic, and arsenic and its compounds are used in pesticides, herbicides and pesticides. Until 20 13, organic arsenic pesticides completely withdrew from the historical stage of pesticides because of its adverse effects on product quality and safety and ecological environment, but there were still residues in soil, and all products contained arsenic, which may be one of the reasons.
How to choose rice?
(1) Look at hardness: the hardness of rice is determined by the content of protein. The harder the rice is, the higher the protein content and the higher the cutin rate (transparency). Generally, new rice is harder than old rice, rice with low water content is harder than rice with high water content, and late rice is harder than early rice.
(2) Look at the white belly: there are often opaque white spots on the abdomen of rice. White spots are called "heart white" in the center of rice grains and "abdominal white" in the outer abdomen. Belly white rice is low in protein content and contains more starch. Generally, rice with high water content, immature rice and immature rice after harvest has a big white belly.
(3) Look at the waist explosion: The waist explosion is caused by the sudden heating of rice during the drying process, and the moisture inside and outside the rice grains is out of balance. Fried rice tastes rotten and endogenous, and its nutritional value is reduced. Therefore, when selecting rice, we should carefully observe the surface of rice grains. If there are one or more transverse cracks on the rice grain, it means that it is popcorn.
(4) Look at the yellow grains: rice is hulled and ground, and normal rice is generally white (purple rice, Redmi, etc.). ). During the harvest period, if the rice is not threshed and dried in time in case of high temperature and rainy weather, the rice quality is easy to turn white, and the processed rice often has yellow grains, which can turn the whole batch of rice yellow in severe cases. Too long or improper storage of rice will also make the processed rice with yellow grains or the whole batch of rice yellow. The main reason for the yellowing of rice is the color formation reaction of nutrients in rice. It is generally believed that amino acids in grains react with sugars to produce color, which is also called non-enzymatic browning.
(5) Look at the freshness: new rice is generally white and shiny, with a fresh aroma; The color of old rice became darker, the viscosity decreased, and the original flavor of rice was lost. Therefore, we should carefully observe the color of rice grains. The rice with gray powder or white grooves on the surface is old rice, and the more it is, the older it gets. At the same time, pick up the rice and smell it If it smells moldy, it means old rice. Old rice tastes light, rough and has low viscosity.
5 strokes of rice
Look at the normal rice grains, which are uniform in size, full, smooth and shiny. If the color of rice grains is abnormal, such as blue-green or dull, there are yellow or light black spots in the depression, and there is a little white component in the bud embryo, it may be oily rice or old rice.
Touch it with your hand and insert it up and down several times. If there are impurities such as rice flour and bran on your hand, it is normal rice. If the hand is slippery, greasy and shiny, it may be rice mixed with oil.
Smell a little rice, rub it with your hands, and smell it again. Good rice is fragrant and has no peculiar smell.
Take a few grains of rice and chew them carefully in your mouth. Good rice tastes slightly sweet and has no peculiar smell.
Soak a little rice and take it home. Soak in a small amount of hot water for 5 10 minutes to see if there will be more impurities, oil stains and wax stains. When you twist the soaked rice by hand, you can feel obvious greasy feeling, or there are oil stains floating on the water, which is mixed rice.
It is wise to eat healthily.
Experts say that eating rice wisely can bring balanced nutrition to the body.
The first principle-try to make rice "light"
Try not to add oil to rice, so as not to add extra energy and avoid raising blood lipid after meals. In addition, try not to add salt, soy sauce and monosodium glutamate to rice, and avoid adding more salt.
The second principle-try to make rice "coarse"
Try to reduce polished rice and eat less glutinous rice. Excessive intake will affect the control of blood sugar and blood lipids. Only by taking enough fiber can we effectively reduce the digestion speed of rice and absorb cholesterol and fat in the intestine, thus reducing postprandial blood sugar and blood lipid. This can also make people eat slowly and consume less, which is conducive to weight control.
Some rice with nutritional and health care value, such as brown rice, black rice, germ rice, etc. It has a "rough" taste and can be cooked with polished rice, which can not only balance nutrition, but also be easily accepted.
The third principle-try to make rice "messy"
When cooking, it is best not to use a single rice. You can choose different combinations according to your physical condition. For example, red bean rice and peanut oatmeal rice porridge are very suitable for chronic patients. On the one hand, adding these food raw materials increases B vitamins and minerals, on the other hand, it can supplement the nutrition of protein, reduce animal food and ensure adequate nutrition. At the same time, it can effectively reduce blood sugar reaction and control the increase of blood lipid. Among them, the combination of beans and rice is the most suitable, because beans are rich in dietary fiber, in which the digestion speed of starch is very slow, and there are some ingredients that delay the conversion of starch into glucose, such as tannin and phytic acid, which have excellent effects on preventing chronic diseases.
Misunderstanding of rice consumption
(1) The whiter and brighter the rice, the better the quality.
This kind of consumption advocacy leads to over-processing of rice production enterprises, resulting in nutrient loss. Compared with ordinary rice, rice with high processing precision has higher appearance brightness, less bran powder, whiter rice and better taste.
However, most nutrients (such as protein, fat, cellulose, minerals and vitamins) except carbohydrates in rice are concentrated in pericarp, seed coat, endosperm, aleurone layer and embryo. Because of the high processing precision, there are many losses of protein, fat, vitamins and minerals in Kangpi, so the nutritional components of "polished rice" are obviously lower than ordinary rice. With the popularization of nutrition science knowledge, brown rice has been paid more and more attention and loved by people, and it is regarded as the nemesis of "civilized disease", and a craze for eating brown rice is gradually taking shape.
(2) Nutritional fortified rice replaces ordinary rice.
Enriched rice refers to the finished rice made by adding some nutrients to ordinary rice. At present, the main nutrients used to strengthen the nutrition of ordinary rice are vitamins, minerals and amino acids. Rice husk and germ are rich in nutrients such as protein, fat, vitamins and minerals. In the process of rice milling, with the grinding of cortex and germ, the nutrients contained in it are also lost. The higher the accuracy of rice processing, the more the loss of nutrients. In addition, rice will lose a lot of nutrients in the process of elutriation and cooking. Nutritional fortification of ordinary rice can not only supplement the lost nutrients, but also increase some nutrients that rice itself lacks, including vitamin B 1, vitamin B2, nicotinic acid, lysine, iron and calcium.
There are two kinds of fortified rice: one is to spray iron, zinc, calcium, vitamins and other nutrients on ordinary rice, mix them and dry them; The other is to crush high-quality rice, and then mix six nutrients, such as vitamin B 1, vitamin B2, folic acid, nicotinic acid, iron and zinc, with rice flour according to the proportion specified in the Recommended Formula for Enriching Rice Nutrition in China, and then press with a mold to restore the shape of ordinary rice. The final product is almost the same as ordinary rice in color and quality, and the rice grains are evenly mixed at a ratio of 4% to 5%.
Eating fortified rice can improve people's dietary nutrition, supplement the deficiency of micronutrients, meet the normal needs of human physiology, reduce the occurrence of various nutritional deficiencies, and thus improve people's health. This kind of rice is very popular with consumers in developed countries such as the United States.
At present, fortified rice can not replace ordinary rice to become the dominant market. From the perspective of various countries, ordinary fortified rice is dominant in a country, which is often promoted by government decrees. In our country, we only advocate strengthening rice. In the countries advocated, it is reasonable in terms of the existence and structure of the product market. It is impossible for the so-called fortified rice to completely replace ordinary rice in China. Combined with China's consumption level, economic level and nutritional deficiency, as well as the differences in lifestyle and diet structure between the east and the west, we think that Nutrition enriched rice only enriches products on the basis of dietary nutrition enhancement called by the State Council. At present, there is no plan to replace ordinary rice with nutritious enriched rice in China, and people's needs are diversified, so it is impossible to completely replace ordinary rice with nutritious enriched rice.
Excessive washing and kneading of rice during cooking.
Don't wash rice too much, because rice contains some water-soluble vitamins and inorganic salts, a large part of which is in the outer layer of rice grains. Too much washing or stirring will cause a large loss of nutrients on the surface of rice grains. Meanwhile, rice should not be soaked for a long time. If soaked for a long time before elutriation, some inorganic salts and soluble vitamins in rice grains will dissolve in water, and then lose more after elutriation.
In the process of rice washing, the loss rate of vitamin B 1 can reach 25%-50%, the loss rate of vitamin B2 and nicotinic acid can reach 20%-25%, and protein, fat, sugar, etc. There will also be different degrees of loss. In addition, rice is easily broken when soaked for a long time. Therefore, attention should be paid to the following points when washing rice:
1. Wash with cold water, not tap water or hot water.
2. The consumption of water and the times of elutriation should be minimized.
3. Don't rub hard and stir excessively.
4. Don't soak rice before and after washing rice. If the rice has been soaked after washing, the soaked rice washing water should be put into the pot together with the rice.
Family preservation method of rice
Rice is one of the most important staple foods in China, and it is also a food with rice as its main raw material. The characteristics of rice make it difficult to preserve for a long time.
Rice is the product of hulling and peeling after rice processing. Rice loses its shell protection and its embryo and cortex are damaged, so it is sensitive to the influence of external temperature, humidity and oxygen. It breathes strongly, pests and germs are easy to directly harm, and it is easy to absorb moisture, be heated, be moldy, turn gray, age, be eaten by insects or burst the waist. Under the same temperature and humidity, the equilibrium moisture of rice is higher than that of rice. Broken rice and rice bran are added to rice, which blocks the gap of rice pile and has poor thermal conductivity; At the same time, rice bran carries more bacteria and contains more fat, which is easily oxidized and increases the acidity of rice; The moisture absorption capacity of rice is also related to the content of bran powder and broken rice. The high content of bran powder and broken rice makes the deterioration speed of rice more prominent during storage. The fat contained in bran powder is easily oxidized and decomposed to form fatty acids, which increases the acidity of rice. Therefore, rice is more susceptible to moisture, fever, mildew, insects and storage than rice.
The rice stored at home should be kept in a cool, ventilated and dry place to avoid high temperature and light. When rice is filled in a container (rice barrel or rice cylinder), it should be lit with paper before filling, and the container should be dried and disinfected. After the rice is bought back, put it in a rice bucket or rice vat, cover it and put it in a dry and ventilated place one foot from the ground. When eating, adopt the method of bringing forth the old and bringing forth the new, eat the bought rice first, and then eat the bought rice to prevent mildew, mouse and insect pollution.
Clean empty rice barrels and empty rice tanks frequently, and remove bran powder and eggs from the tanks. In rainy season and midsummer season, in order to prevent mildew and insects, you can put a crab shell or turtle shell or garlic in the lunch box. If there are insects in rice, Mi Chong should be removed first, and then pepper and fennel should be wrapped in gauze and placed on the surface of rice. Don't cover the rice jar (barrel) at once.
Rice is not easy to store for a long time, especially in summer. If stored for a long time, rice will easily age. The color of old rice darkens, the fragrance disappears, furoic acid appears, the acidity increases, the viscosity of rice decreases, the porridge is not thick, and the edible quality decreases. Families should not buy too much rice at a time. If you buy oxygen-free packaged rice, you should eat it as soon as possible after opening the bag.
When steaming rice at ordinary times, do you simply put the rice in the pot to cook? In fact, you only need a few simple tricks to make your rice particularly delicious! Come and try it ~
Ham and corn rice
Ingredients: 2 cups of boiled rice, ham 120g, corn kernels 120g, carrot 80g, onion 100g, 2 cups of water, a little chopped green onion, 2 teaspoons of salt1/and 2 teaspoons of onion oil.
Cooking method
1. Cut the ham into small pieces; Wash carrots and onions, peel and dice. Put it aside.
2. Wash and drain the white rice and put it in an electric cooker with water and all seasonings. Cook 1 ham slices, diced carrots and diced onions, and press the cooking button to cook until cooked.
3. Method 2 After cooking, open the electronic pot and mix well, sprinkle with a little chopped green onion.
Diced carrot rice
Ingredients: 2 cups of uncooked rice, 1 diced carrot.
Cooking method
Put the rice and diced carrots into the pot together. When the rice is cooked, most carrots will float on it, and then gently stir them evenly to make them evenly distributed.
Shannon pumpkin rice
Ingredients: pumpkin 400g, rice 200g.
2 tbsp seasoning and cooking oil, 1 teaspoon salt.
Cooking method
1. Peel and remove seeds from pumpkin and cut into small pieces; Wash the rice for later use;
2. Heat the wok with 2 tablespoons of cooking oil for 7 minutes, then add pumpkin pieces and stir fry for 1 minute;
3. Pour in the washed rice and pumpkin, stir well, then add about 500 ml of water to cover the rice, cover it, turn to medium heat 10 minute, add salt, stir well, then simmer with minimum fire 1520 minute, and drain the water.
Remember when you said that home is the only castle, and it continues to flow with the Xiang Tao River? The so-called happiness, barefoot in the field, tired of chasing dragonflies? "
Jay Chou's "Daoxiang" is melodious, and the lyrics are full of love for rice fields, which is the most primitive call in the hearts of every China people. Paddy fields have raised thousands of people in China, Qian Qian. For thousands of years, rice has been the staple food in China. It is an important responsibility of every rice producer to call for rice safety and create healthy, organic and high-quality rice.