Nutritional components in cooked food
Food contains many nutrients needed by human body, including sugar, fat, protein, vitamins, inorganic salts and water. According to their functions in the body, these nutrients can be divided into three parts: constituent substances, energy substances and regulatory substances. Protein, inorganic salts and water are constituent substances, sugar and fat are energy substances, and vitamins are regulatory substances.
Sugar, also known as carbohydrate, includes monosaccharide, disaccharide and polysaccharide. Monosaccharide is the simplest carbohydrate such as glucose and fructose. Disaccharides are composed of monosaccharide molecules, such as sucrose, maltose and lactose. Polysaccharide consists of many monosaccharide molecules, such as starch and cellulose. Food contains a variety of sugars, such as grain seeds, sweet potatoes and carrots, starch, fruits and roots and stems of some plants contain sucrose, fructose and glucose, milk contains lactose and honey contains glucose and fructose. The main function of sugar is to provide energy for life activities. When 1 g sugar is completely oxidized, it can release about 16800 joules of heat. More than 70% of the energy needed by the human body is provided by the oxidative decomposition of sugars.
Fat consists of fatty acids and glycerol. The fat of warm-blooded animals such as pigs, cattle and sheep mainly contains saturated fatty acids, which are solid. The fats of warm animals and plants, such as cod liver oil and rapeseed oil, mainly contain unsaturated fatty acids and are in liquid state. Generally speaking, fat is stored in the body as a spare substance. In plants, most of the fat is stored in seeds * * * soybeans and peanuts * * *; In animals, most fat is stored in eggs, subcutaneous tissue and mesentery. Fat is the main substance for human body to store energy. When 1 g fat is completely oxidized, it can release about 37700 joules of heat, which is more than twice that of sugar molecules.
Protein is a biomacromolecule, which is generally composed of 100 amino acid molecules. Protein is the main component of cells, the substance of enzymes and the energy substance of the body. When 1g protein is oxidized, it can release about 16800 joules of heat. There are more than 20 kinds of amino acids that make up protein, among which 8 kinds of amino acids, such as valine, leucine, isoleucine, threonine, methionine, lysine, phenylalanine and tryptophan, cannot be synthesized by human body and must be supplied by food, which are called essential amino acids. Other amino acids, such as glutamic acid, alanine and glycine, can be synthesized by the human body and do not need food supply, so they are called non-essential amino acids.
Vitamins are trace organic substances necessary for human growth and metabolism. At present, there are more than 20 known vitamins, which are divided into two categories: water-soluble and fat-soluble. Water-soluble vitamins mainly include vitamins B 1, B2, B6, B 12, C, etc. Fat-soluble vitamins mainly include: vitamins A, D, E, K, etc. Most vitamins cannot be synthesized in the body and must be supplied through food.
Vitamin A can promote the growth and development of human body and enhance the disease resistance. When the human body is lacking, epithelial tissue will be keratinized and the panel will be rough, which is easy to suffer from night blindness and respiratory infectious diseases. Vitamin A is soluble in fat and has a high content in animal foods, such as animal liver, cod liver oil, cream and egg yolk. Some plant foods, such as carrots, tomatoes and yellow corn, contain a lot of carotene, which can be converted into vitamin A in human body.
Vitamin B includes B 1, B2, B6 and B 12. It has many effects on the human body. For example, vitamin B 1 can maintain the normal metabolism of human body and the normal physiological function of nervous system. When lacking, it is easy to suffer from neuritis, loss of appetite and indigestion. If it is serious, it will cause beriberi, heavy lower limbs, numbness of hands and feet, and rapid heartbeat. Rice bran, wheat bran, lean pork, peanuts, soybeans and other foods all contain more vitamin B 1.
Vitamin c is also called ascorbic acid. When it is deficient, capillaries become brittle and easy to rupture, leading to blood vessels bleeding under the skin and gums and becoming scurvy. Vitamin C mainly exists in fresh fruits. Pepper, sugar cane, tomatoes, dates, oranges and other foods are very rich in vitamin C.
Vitamin D can promote the absorption and utilization of calcium and phosphorus in small intestine and promote the normal calcification of bones. Lack of calcium will lead to calcium deficiency and skeletal dysplasia. Cod liver oil, egg yolk, animal liver, kidney and almond are rich in vitamin D. In the human body panel, there is a kind of cholesterol, which can be converted into vitamins after being irradiated by sunlight and ultraviolet rays. Therefore, people often sunbathe, which is good for their health.
Inorganic salts are an important part of human body, which can be divided into main elements and trace elements. The main elements are calcium, phosphorus, magnesium, sodium, potassium and chlorine, and the trace elements are iron, copper, iodine, manganese, cobalt, zinc and fluorine. Inorganic salts depend on food supply. For example, sodium and chlorine mainly come from table salt. Calcium, phosphorus and iron can meet the needs in general foods, but foods containing more calcium should be supplemented during children's development. Many inorganic salts are components of cells, enzymes, hormones and vitamins. For example, calcium, phosphorus and fluorine are the components of bones and teeth, iron is the component of hemoglobin, iodine is the component of thyroid hormone, zinc is the component of various enzymes, and diamond is the component of vitamin B 12. Inorganic salts are also indispensable substances to maintain normal physiological functions. For example, sodium, potassium and calcium are related to the normal excitability of nerves and muscles, chlorine is related to the formation of gastric acid and the activation of salivary amylase, zinc is related to the synthesis of insulin, and cobalt is related to hematopoietic function.
Cook food at 70℃
First, the cooking method of food at 70℃
"70℃ food cooking method" emphasizes cooking food at 70℃. It can not only keep food delicious, but also effectively inhibit the oxidation of ingredients, maintain vitality, and make ingredients have a longer taste appreciation period than in fresh state.
Chicken balls cooked at 70℃ are much more delicious than those cooked at 100℃. The application of "70℃ cooking method" can not only retain the nutrition of food, but also improve the flavor and sweetness at the same time. Simple cooking can make food delicious and healthy, and it is a cooking method that can make ingredients produce the best flavor.
Second, the delicious principle of cooking at 70℃
The basic principle of "70℃ cooking method" is to cook food at 70℃ for 20 minutes to keep the food fresh and nutritious. Because some foods are cooked at 70 degrees, their life energy content is higher than the fresh state of the ingredients, and because the heat energy of cooking permeates from all directions, there will be no uneven heating, which is a simple cooking method for anyone to cook delicious food.
1. Preserve pectin to rejuvenate vegetables.
Vegetables contain pectin, which is responsible for bonding plant cells. Pectin will differentiate at a proper temperature, but it will lose its viscosity and soften when it meets the high temperature of 100 degrees. On the contrary, if cooking at a lower temperature, the adhesion of pectin will be enhanced, which will naturally keep plant cells alive.
2. Increase sweetness, aroma and palatability, and double the taste.
Fresh ingredients contain a lot of enzymes. If heated at high temperature, almost all enzymes will die. However, if heated to 70 degrees, some enzymes can be retained to promote ripening, thus increasing the delicacy and sweetness of food and enriching the aroma. Because 100 degree will destroy the cell wall of food, 70 degree will not, thus maintaining the taste and crispness of food.
3. Improve the nutritional value. Mushrooms are three times more nutritious.
Using the 70-degree cooking method, the nutritional value of some ingredients is even higher than that of fresh food. For example, the vitamin nutrition contained in vegetables, especially vitamin C, is almost destroyed below 100 degrees; But below 70 degrees, the damage degree can be greatly suppressed.
For example, the content of vitamin C in spinach cooked at 70 degrees is 2.2 times that of spinach cooked at 100 degrees. Gallic acid contained in mushrooms has the function of making food delicious, and it has tripled after cooking at 70 degrees.
4. Storage is better than fresh state
After harvesting, vegetables will gradually oxidize over time; In the process of cooking such as marinating and frying, oxidation can also be triggered. For example, after the apple is cut, the incision gradually turns brown, which is caused by oxidation. Although oxidation is different from corruption, it will still lose its flavor and reduce the preservation of ingredients.
Because cooking at 70℃ is heated in stable steam with little air, oxidizing substances will drop with condensed water, so it can effectively inhibit the oxidation of ingredients.
Cooking method of eggs
Fried eggs-crispy outside and tender inside
Expert comment: The fried eggs are very crisp, but it also means that the protein in that part has changed, which reduces the utilization rate of eggs. The darker the fried eggs, the more serious the degeneration of protein. If burns have occurred, substances harmful to human health will also be produced.
Boiled eggs-the simplest and most nutritious
Expert comment: Boiled eggs are the simplest way to eat, with the best nutrition storage and high digestibility. Another way to cook with water is poached eggs. You can cook it directly in water, or you can cook it directly with eggs when cooking soup and noodles. Salted poached eggs can be added with tomatoes, vegetables and so on. And sweet can also add fermented grains, red dates, medlar and other ingredients. Boil poached eggs until the water boils. Cook slowly with low heat to keep the appearance beautiful. Except for routine.
You can also fish out the boiled poached eggs, fry a fish-flavored sauce or sweet and sour sauce on them, and make them into fish-flavored poached eggs, sweet and sour poached eggs and so on.
Sauce explodes eggs ―― It is recommended to put less tea.
Expert comment: Tea egg is a kind of marinated egg with sauce. The traditional method of making tea eggs is to break the eggshell after the eggs are cooked, and then put the eggshell into the soup boiled with tea, soy sauce and salt. The nutrition of pickled eggs is similar to that of boiled eggs, but eat less tea eggs. Protein is the most abundant nutrient in eggs, but the tannic acid in tea will affect the absorption of protein. In particular, you can't eat tea eggs soaked overnight, otherwise it will increase the burden on the stomach. In fact, you can make an improved version of "tea eggs". There is no need to put tea leaves, and the juice is made of star anise salt soy sauce, which tastes good.
Fried eggs-delicious ingots
Expert comment: Common ways to eat fried eggs are fried chicken egg packets, tiger skin eggs, sea cucumber fried eggs, wing elbows and so on. Fried chicken and egg buns are usually made for breakfast, fried with fried dough sticks and then fried with eggs. Boil the tiger skin eggs, peel them, fry them, and then add seasoning. You can make it sweet, sour, salty and fresh, or sprinkle cumin noodles, which tastes good. Contrary to what most people think, not all nutrients will be lost in fried eggs. There will be some loss of protein outside the fried egg, but the nutrition in the egg yolk can still be well preserved.
Egg drop soup-simple and delicious
Expert comment: Of course, eggs can also be made into soup. There are two ways to make soup. One is to fry eggs into egg rolls, add water to the pot to boil, and then add other ingredients and seasonings. The other is to boil other raw materials first, and then add the egg flowers after the water is boiled. Soups that are not sticky, such as laver egg drop soup, tomato egg drop soup, spinach egg drop soup, cucumber egg drop soup and loofah egg drop soup; There are West Lake beef soup, Xishi seafood soup, eggplant corn soup and so on. Egg custard and egg soup are easier for children to digest and absorb.