Paper on food nutrition and science 1
Study on food nutrition and nutritious food
It has become a very urgent and important task to guide the reform and adjustment of China's food structure in time, promote the coordinated development of food production and consumption, and establish a scientific and reasonable food structure as soon as possible, which is related to the improvement of the overall quality of our people and the development and prosperity of our national economy. This paper introduces the current food structure of China people and some problems existing in the food industry production, expounds the dialectical relationship between nutrition, hygiene and color, aroma and taste, and points out the development direction of the food industry mainly consisting of functional food and fermented food.
Food structure; Food nutrition; Food development
Nutritional food itself is the material basis for human beings to improve their physique, prolong life, reproduce and improve the quality of their offspring. Microscopically, all kinds of nutrients in food should meet the requirements of human life and physiology. The basic task of modern food science is to study how to balance, develop and produce nutrients in food scientifically and reasonably. Nutrition, health, science and rationality? Food. Of course, the color, aroma and taste in food are important conditions in food, but they are not decisive factors. Before the 1970s, developed countries such as the United States produced all kinds of foods with high fat, high sugar and high artificial additives simply to suppress color and taste, which led to the so-called cardiovascular diseases and diabetes in the United States at that time. Rich disease? Almost more than 10% of its total population, especially blind pursuit? Refined powder, polished rice, essential oil? Under the premise, the number of cancer patients and genetic patients is also high. The above diseases once reached 15% of the total population. To this end, the United States uses official, semi-official and non-governmental research institutions to conduct research, and proposes to develop balanced food and functional food to adjust the structure of a food. After nearly 20 years of efforts, this situation has been contained and improved. Looking back on China's reform and opening up for more than ten years, due to economic development, life has improved.
On the one hand, is it caused by unbalanced diet or overnutrition? Abundance disease? And it is still developing at a high speed. On the other hand, due to the single variety of food or malnutrition or simple emphasis on color, fragrance and taste, on the one hand, children are malnourished and lack of iron, zinc and multivitamins. 20 12 survey data of primary school students in Harbin showed that children were deficient in vitamin c by 40%, vitamin a by 70% and calcium by 60%, and the rickets rate in northern areas was increasing day by day.
On the other hand, from the current health status of the elderly, more than 70% people suffer from cardiovascular diseases, Alzheimer's disease, diabetes and bone diseases to varying degrees, and they are still on the rise. Of course, there are many pathogenic factors, but the imbalance of nutrition in food can not be ignored. As people enter the aging stage, their whole body metabolism enters a new balance adjustment, and they need all kinds of nutrients that meet the requirements of the physiological stage of aging, not only the quality and quantity of nutrients, but also the balanced supply of nutrients is particularly important, which destroys the balance between these nutrients. Too much or too little of a certain nutrient in the diet will cause metabolic disorder of the elderly and produce corresponding diseases. For example, various refined foods, such as polished rice, refined flour, essential oil, refined sugar, refined salt and so on. At present, it is popular, resulting in a large loss of vitamins, trace elements such as chromium and zinc, some of which can reach more than 85%. Relatively, some harmful elements such as lead, tin, vanadium and aluminum exceed the standard. Therefore, there will be more and more metabolic diseases, cardiovascular diseases, diabetes and dementia in the elderly. At present, all kinds of fortified foods on the market will be effective only if there are some special symptoms caused by nutrient deficiency or excess, such as osteomalacia caused by calcium deficiency and incomplete keratosis caused by zinc deficiency. For cardiovascular diseases or diabetes caused by chromium deficiency, we can produce special foods rich in calcium, zinc or chromium to meet the needs of patients with these diseases, instead of so-called nutritious foods labeled with amino acids and trace elements, which can cure all diseases and stay healthy forever. In fact, any kind of food contains protein, amino acids and trace elements. But the difference lies in the number, type and proportion of their mutual cooperation. Only quantity and variety can explain what is high nutrition, and there is no nutrition in food.
Scientifically fortified food, in essence, is a food that helps people with insufficient or excessive nutrition to balance their metabolism. Therefore, it has biological functions, which we call functional food. Because it is functional, it is specific and cannot be applied to all aspects casually. Otherwise, it will not only cause economic and mental losses to people, but also have the opposite effect and have a negative impact on health.
Someone suggested? Back to nature? From the food point of view, we can't help but think that all foods from nature are edible, and there is no choice and no scientific preparation. Although some natural foods contain high nutrients, it doesn't mean high nutrients. High-nutrient substances should be highly absorbed and utilized by human body, which can greatly promote the metabolic balance of human body and improve human health and physique. This kind of food should be called highly nutritious food. High nutritional content does not mean high nutritional value. Some natural foods contain high nutrients, but they also contain harmful ingredients that antagonize the body's absorption of nutrients. Spinach, for example, is a vegetable with good color, fragrance and taste and rich in vitamins, but its high oxalic acid content will affect the body's absorption of calcium, iron and zinc. Pregnant women, children and the elderly should pay attention. Shrimp is a delicious high-quality food, which contains a lot of lecithin and mineral elements, but it contains a pentavalent arsenic compound, which will not do much harm if eaten alone. For example, if you eat it with foods rich in vitamin C, you can turn pentavalent arsenic into trivalent arsenic, which makes people toxic. Natural food or green food (generally refers to pollution-free food) is influenced by regional water sources, seasons, climate, environment, vegetation and cultivation conditions, and contains different nutritional components. Not all the nutrients contained are balanced. Some natural foods are rich in nutrients, while others are low in nutrients, so the ratio can't be so appropriate. Moreover, many foods contain various substances that are antagonistic to human absorption. Therefore, while attaching importance to the use of natural food, we should pay attention to adding appropriate additives scientifically. Excessive or one-sided use of natural foods is neither economical nor scientific. Combined with the diversification and mutual cooperation of food ingredients, the nutrition in food can produce biological complementarity, which is beneficial to the absorption and utilization of nutrients by human body.
The highest purpose of food is that the nutrients it contains can be well absorbed and utilized by the human body after eating, so as to meet the needs of balancing metabolism and promote the normal operation of various functions of the body. In the process of food production, processing, transportation and storage of raw materials and finished products, we must attach great importance to hygiene, avoid the pollution of harmful pathogens, parasites, rodents, harmful air components, dust and other pollutants, and ensure that food meets the national hygiene standards, which is a necessary condition for promoting food to enter the human body effectively. In order to ensure that the nutritional components of food are not lost, the nutritional value is high, and the color, smell and taste meet the requirements, the food combination and processing technology in food must be scientific and reasonable, which is the premise and means to ensure the quality of food. Without one of the four, it is impossible to form food that meets the requirements of people and modern production. Therefore, the food industry should purposefully develop the production of functional foods on the basis of developing popular nutritious foods necessary for daily life. On the basis of meeting people's requirements for color, fragrance and taste, it compensates the lost nutrients in the refining process, improves its nutritional value and promotes human health. At the same time, according to the needs of different groups of people, different nutritious foods or functional foods are produced.
Nutritional food or functional food is a kind of nutritional food produced according to the physiological and nutritional needs of different people. This kind of food is not only a health food, but also a dietotherapy food for improving physique and enhancing immunity. Its main function is to promote the physiological balance metabolism of human body. According to the scientific balanced nutrition theory and the characteristics of different nutritional needs of different groups of people, the nutritious food produced by corresponding processing technology is not only functional, but also targeted and targeted. This kind of food has aroused widespread concern in the world, and foreign countries have also invested considerable energy in research and production, and achieved great economic and social benefits. In the past decade, the number of cardiovascular diseases and diabetes in the United States has dropped significantly, and the average life expectancy in Japan and Germany has increased by 3-5 years, which is closely related to the emphasis on nutrition and the development of functional foods.
It can be seen that in the future, especially in the 2 1 century, the food industry should develop in a scientific breadth and depth, focusing on functional foods and fermented foods, and combining China's national conditions and natural resources for production? Nutrition, health, science and rationality? Foods with various functions and grades that can meet the needs of different people in China will have a great impact on developing China's economy, enhancing human health and ensuring the prosperity of future generations. [partial]
refer to
[1] People's Republic of China (PRC) Food Safety Law. Beijing: China Legal Publishing House, 2009.
Paper on Food Nutrition and Science Part II
Discussion on nutritional value of cereal food
Abstract: With the rapid economic development in China, great changes have taken place in people's diet structure. The proportion of grain consumption in residents' diet is decreasing, replaced by the increase of oil and livestock meat consumption. It can be seen that the position of cereal as the pyramid of dietary structure has obviously deviated. Therefore, fully understanding the nutritional value of cereals can not only promote the healthy growth of human body and prevent various chronic diseases, but also have great reference significance for correcting people's unreasonable diet structure.
Keywords: nutritional value of cereals
China Library Classification Number R4 Document Identification Number A1671-8801(2013) 09-0076-02.
Cereal food mainly includes barley, wheat, oats, rice, millet, corn, buckwheat and sorghum, which is the staple food of human beings and the most important and economical source of energy needed by human body. From the perspective of nutrition, combined with my own work practice, the author will comprehensively analyze the nutritional distribution, main nutritional components and important functions of cereals to the human body.
1 Nutritional distribution of cereals
Most cereal seeds have similar basic structure, which consists of four main parts: husk, aleurone layer, endosperm and germ. The total weight of cereals is 13% ~ 15%, aleurone layer and endosperm account for 83% ~ 87%, and germ accounts for 2% ~ 3%. As the shell of grain, the main components are cellulose and hemicellulose, which contain a certain amount of vitamins, inorganic salts and high ash and fat, so the edible value is not high. Aleurone layer, located under the chaff, is rich in protein, fat, vitamins, cellulose and other nutrients. As the main component of grain, endosperm is mainly composed of starch cells, which contain a lot of starch and a certain amount of protein, and its protein content decreases from the periphery of endosperm to the center of endosperm, while the contents of fat, vitamins and inorganic salts are relatively small. The germ of grain is rich in fat, protein, inorganic salts, B vitamins, vitamin E and some enzymes.
2 Main nutritional components of cereals
Due to the influence of varieties, climate, soil, fertilizers and processing methods, the nutritional components of cereals will also show certain differences, but in general, their main nutritional components include the following:
(1) carbohydrates. Cereals contain a lot of carbohydrates (about 70 ~ 80%), and the main component is starch, which is concentrated in starch cells of endosperm. According to the different molecular structure of starch, cereal starch can be divided into amylose and amylopectin. There are some differences in solubility, viscosity and digestibility, and the proportion of their contents in different grains is different, which makes their finished products show different flavors. Among them, amylose food is easy? Aging? , forming resistant starch that is not easy to digest, and amylopectin is easy to gelatinize food and improve digestion rate. In a word, the utilization rate of cereal carbohydrates in human body is high (about 90% or more), and it is the most economical and ideal energy source for human body.
(2) protein. The protein content of cereals is generally between 8 ~ 15%, which is mainly composed of gliadin and glutenin. And the protein content in the outer layer of the grain is the highest, so the protein content of refined rice flour with excess husk removed is much lower than that of coarse rice flour. In addition, the contents of lysine, threonine, tryptophan, phenylalanine and amino acids in grain protein are very low. For example, millet and flour have the least lysine, while corn is relatively deficient in lysine and tryptophan. Therefore, cereal protein and protein should be mixed when eating, so as to effectively improve the physiological value of cereal protein.
(3) fat. The fat content in grains is low (about 2%). In common cereals, the fat content of rice and wheat is about 1% ~ 2%, and that of corn and millet is about 4%. In addition, there is a certain amount of lecithin in aleurone layer and embryo of grain, but lecithin is easy to lose or flow into by-products during grain processing. Such as rice bran oil, oryzanol and sitosterol extracted from rice bran, and germ oil extracted from wheat germ and corn. These oils contain up to 80% unsaturated fatty acids and 60% linoleic acid, which can reduce serum cholesterol and prevent atherosclerosis.
(4) vitamins. There are many B vitamins in cereals, mainly vitamin B 1, vitamin B2 and nicotinic acid, among which thiamine (VB 1), riboflavin (VB2), nicotinic acid (VPP), pantothenic acid (VB3) and pyridoxine (VB6) are more in aleurone layer and embryos of cereals. However, these nutrients are easily lost with processing, so the content of vitamins in refined rice flour is less.
(5) others. There are also a certain amount of inorganic salts (about 1.5%), cellulose, minerals and so on. In cereal, the cellulose in cereal can stimulate the gastrointestinal tract and prevent constipation. Minerals are mainly phosphorus and calcium, and most of them exist in the form of phytate, which improves the utilization rate of phosphorus and calcium.
3. Effects of cereals on human body
There are many kinds of human foods, and the nutrients contained in all kinds of foods are not exactly the same. According to research, cereal contains many minerals that the human body lacks. These minerals can not only balance the nutrients needed by human body and prevent obesity, but also improve human immunity and reduce the incidence of many chronic diseases. Therefore, eating more grains is of great benefit to human body. For example, eating rice can not only provide essential nutrients and calories for human body, such as starch, protein, fat, vitamin B 1, vitamin B2, hydrochloric acid, vitamin C, calcium, phosphorus, iron, etc., but also has the functions of strengthening the spleen and stomach, invigorating the middle energizer, nourishing yin and promoting fluid production, relieving restlessness and thirst, and stopping diarrhea. Can be used for spleen and stomach weakness, polydipsia, malnutrition, and physical weakness after illness. While corn is plain and sweet, which is not only nutritious, but also contains protein, fat, sugar, vitamins and essential trace elements. Moreover, vitamin E, lecithin and glutamic acid in corn have a good effect on brain health and anti-aging. Cellulose can absorb cholesterol in human body, prevent arteriosclerosis and accelerate intestinal peristalsis, prevent constipation and prevent the occurrence of rectal cancer; Magnesium can relax blood vessels and maintain the normal function of myocardium, which is beneficial to patients with hypertension, coronary heart disease and fatty liver. As a strong antioxidant, selenium can scavenge free radicals in the body, resulting in insufficient supply of molecular oxygen to tumor cells, thus inhibiting the growth of cancer cells; In addition, corn also has diuretic, cholagogic, hemostatic and antihypertensive effects, and has certain auxiliary effects on treating anorexia, hepatitis, edema, urinary tract infection and other diseases. In short, eating cereals can help the body maintain a low level of homocysteine, reduce the risk of diseases such as hypertension, heart disease, stroke and dementia, lower blood sugar, reduce insulin resistance, reduce the risk of type 2 diabetes and metabolic syndrome, effectively reduce the incidence of chronic diseases, promote the health of digestive tract, and prevent fatty liver and other diseases.
4 conclusion
With the development of economy and the improvement of people's living standards, people's understanding of nutrition and health has changed greatly, and they tend to eat animal food more and more, while the consumption of cereal food has decreased greatly. However, the nutritional value of grain and its effect on human body can not be ignored. Therefore, for the sake of human health, we should insist on eating grains in people's diet structure and keep the main position of grains in people's diet structure, so as to effectively avoid all kinds of disadvantages brought by high-energy, high-fat and low-carbohydrate diets and ensure people's healthy and beneficial diets.
refer to
[1] Chen Junshi's warm beauty. Modern nutrition fifth edition, Beijing: People's Health Publishing House, 2003,347.
[2] Gong Kuijie, Chen Lirong, Zhao Quansheng. Exploration and prospect of heavy grain diet structure of China residents, Food and Nutrition in China, 20 10( 1)
[3] Cui Chaohui, Zhou Qin, Hu Xiaoqi. Analysis on the Current Situation of Grain and Potato Consumption in China, Food and Nutrition in China, 2008, 3: 33-36.
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