Water and Dietary Fiber
"Tired, I always feel that I can't rest, especially in summer, I always feel that I can't sleep." Recently, with the advent of summer, many people's exhausted state has followed closely. Experts believe that in order to get rid of this sub-health state, it is important to learn to drink water and take in "crude fiber".
Nutrition experts pointed out that sub-health is a very common state of modern people. In addition to the tense pace of life, less activity and excessive stress, nutritional imbalance is one of the most important reasons for this state. Nutritionists remind people to learn to drink water and eat enough dietary fiber especially in summer.
Section One Water
The importance of water for human survival is second only to oxygen. A hunger striker loses all the body fat, half of the Pro, and can barely maintain life, but if the water is cut off and loses 20% of the body's water content, he will soon die. Without the existence of water, no life process can proceed. In fact, as long as the human body loses 5% of water without replenishing it in time, the skin will shrink, wrinkle and dry.
Ⅰ. The content and distribution of water in the human body:
50%-70% of adults are water. The water in the body combines with protein, carbohydrate and fat to form a colloidal state. The osmotic pressure of each part of the body fluid is the same, in which water can often freely communicate through the cell membrane or capillary wall, but the total amount of each remains relatively stable and maintains a dynamic balance.
Ⅱ. The physiological functions of water:
(1) Water is an important component of cells: all tissues contain water, such as blood water up to 97%, muscle 72%, fat 20-35%, bone 25%, and hard teeth also have 10% water.
(2) An important solvent in the body: water has strong solubility, many substances can be dissolved in water, and dissociated into ionic state, and play important physiological functions. Pro and fat molecules that are insoluble in water can be suspended in water to form colloids or emulsions, which are convenient for digestion, absorption and utilization by the body. Water is also a medium for transporting nutrients and excreting waste in the body.
(3) Material metabolism: Water directly participates in the oxidation-reduction reaction in the body, promoting various physiological activities and biochemical reactions. Without water, blood circulation, breathing, digestion, absorption, secretion, excretion and other physiological activities cannot be maintained, and metabolism in the body cannot be carried out.
(4) Adjust body temperature: water has a higher specific heat. When the outside temperature rises or the body generates too much heat, the evaporation of water can make the skin heat dissipation. When it is cold, the water reserves a large amount of heat, and the human body will not cause obvious fluctuations in body temperature due to the low outside temperature. Water is the main component of blood, and the heat generated by material metabolism can be quickly and evenly distributed throughout the body through blood circulation.
(5) Water is a lubricant: moisturizing the skin (softness, flexibility), tears (anti-drying of the eyes), saliva and digestive juice (pharynx lubrication, gastrointestinal digestion) and human joints are all lubricants for the corresponding organs.
(6) Water is closely related to protein, fat and sugar metabolism: metabolism in the body can produce water. 1g of Pro or carbohydrates in the body can accumulate 3g of water.
Ⅲ. The balance of water in the human body:
(1) The source of water in the body: the water in the food intake is about 1000ml/d. Pro, fat and carbohydrates in food are metabolized in the body to produce metabolic water (1g Pro, fat and carbohydrates respectively produce 0.41, 1.07 and 0.55g of metabolic water). A diet with meat and vegetables will produce approximately 12g of metabolic water for every 100kcal heat, such as intake 2500kcalQ, about 300ml of metabolic water produced by biological oxidation in the body. Drinking water is about 1200ml/d.
(2) Water output: Daily water intake should maintain a dynamic balance with the total amount of water discharged through the kidneys, skin, intestines and lungs. The total amount of metabolic waste products and electrolytes excreted in urine every day is about 40-50g, and the kidneys need to urinate at least 1500ml to excrete these metabolic waste products. The skin evaporates 500ml/d. Exhale 350ml/d from the lungs. Large intestine 150ml/d.
Ⅳ. The five rules of healthy drinking water
(1) Appropriate drinking water: Adults need to take in 1500-2500 ml of water per day. People who sweat a lot, are active, and weigh heavier, need a lot of water.
(2) Small amounts and many times: If you drink more than 240ml of water each time, the body cannot absorb it, and it will be excreted from the kidneys quickly. It is better to drink only 100-150ml each time for the body to absorb it better.
(3) Appropriate temperature: drinking water should not be greedy for cold, warm water above 10 degrees is most beneficial to the body.
(4) Drinking water before meals: Some studies believe that drinking water while eating will affect digestion. People who need to lose weight may wish to drink 100-150 ml of water 20-30 minutes before eating. This will not hurt the stomach too much, but also In order to make the stomach feel full.
(5) Replenish water before and after fitness: You can drink 100-150 ml of water 30 minutes before fitness. If the fitness time exceeds one hour, you need to add 100-120 ml of water in between. In addition, after exercise, according to 150% of the weight difference before and after exercise to supplement the lost water.
Section 2 Dietary Fiber
Dietary fiber refers to the fiber that is widely present in plant foods and cannot be hydrolyzed by human digestive enzymes. This type of substance has a wide variety, complex structure, and strong stability. Because it cannot be digested and absorbed by the human body, it gives people a rough taste. , People generally treat it as waste. With the emergence of modern "civilization disease" caused by the "not tolerated" diet and the development of nutritional science, the physiological role of dietary fiber has been increasingly widely used by people Known and valued. Japan has increased the target intake of dietary fiber in the newly revised nutritional requirements. That is, 20-25g per day for adults, 10g per day for toddlers, school children, and senior citizens. This article discusses the physiological characteristics of dietary fiber , Physiological functions and application status in food processing are briefly introduced, aiming to promote the development and more effective use of dietary fiber.
Ⅰ. The physiological properties of dietary fiber
Dietary fiber includes cellulose, hemicellulose, lignin, chitin, pectin, gum and tree paste and other ingredients. Except for lignin, they all belong to carbohydrates, namely polysaccharides. They show large molecules in the human body The various physiological properties of substances can be mainly summarized as fermentation, water retention, adsorption and ion exchange.
1. Fermentability: This is a peculiar property of polysaccharides. Although dietary fiber cannot be degraded by enzymes in the small intestine of mammals, it will be fermented to varying degrees in the large intestine due to the action of bacteria. Pectin, gum and viscose can be Bacteria degrade completely, while cellulose and hemicellulose can only be partially degraded. Dietary fibers from different sources have different fermentability. Fruit and vegetable fibers are easier to ferment than cereal fibers. The physiological changes caused by the fermentation of polysaccharides There are at least three aspects: one is that the produced short-chain fatty acids such as acetic acid, propionic acid, butyric acid can directly participate in metabolism; the second is the decrease in pH in the large intestine, which can lead to changes in the micro-ecological environment, and the third is that the reproduction of bacteria will directly Increase fecal excretion and promote smooth intestinal tract.
2. High water holding capacity: Polysaccharides with polar groups, if gums, gums and some hemicelluloses have a strong water holding capacity, after hydration, they form a cohesive network, which increases the viscosity of the small intestine and diffuses various nutrients The speed slows down, and the volume of polysaccharides increases after absorbing water, which will promote the excretion of feces.
3. Adsorption to organic ingredients: Dietary fiber can adsorb bile acid, cholesterol and a variety of toxic components. Experiments show that: lignin, pectin and other acidic polysaccharides have the ability to adsorb bile acid, and cellulose can adsorb bile acid. It is very low. Clinical trials have further proved that soluble non-cellulose polyconfectionery gum, gar bean gum, etc. can increase the excretion of bile acid and cholesterol in feces, and reduce the concentration of plasma cholesterol.
4. Cation exchange effect: Acidic polysaccharides have strong ion exchange capacity, which can adsorb various mineral elements and electrolytes, especially for heavy metal elements. Therefore, pectin, gums, etc. can be used as heavy metals Antidote. Studies have also shown that the ion exchange effect of dietary fiber can reduce the effectiveness of certain mineral elements and vitamins. For example, pectin may reduce the biological activity of iron and the excretion of vitamin C in the urine, but it is effective against calcium and magnesium. , Copper and vitamin A have less impact.
5. Non-energy fillers: Dietary fiber has a larger volume and swells after being bound by water. It plays the role of a filler in the gastrointestinal tract and causes a feeling of fullness. At the same time, it also affects the available carbohydrates in the intestines The internal digestion and absorption make people less likely to feel hunger.
Ⅱ. The physiological function of dietary fiber
The physiological characteristics of dietary fiber are directly manifested as certain physiological functions.
The main physiological functions of dietary fiber include promoting the smooth flow of the intestines, inhibiting toxic fermentation products, regulating the intestinal flora, reducing plasma cholesterol levels, alleviating the increase in blood sugar after meals and eliminating toxic components. Dietary fiber can promote the smooth flow of the intestines Mainly due to the increase in feces volume and fluency. Different types of dietary fiber have different effects on increasing feces due to different fermentability. The most effective is semolina and cellulose, followed by vegetables and fruits , And fine wheat bran powder, pectin and gums can be completely decomposed by bacteria in the large intestine, which basically does not increase stool volume. Because dietary fiber can keep the intestines open, shorten the residence time of waste in the intestine, and reduce The contact of carcinogens with the intestinal mucosa can inhibit the production of carcinogens and absorb these substances, so it has a better prevention and treatment of constipation and gastrointestinal cancer.
Non-cellulosic polysaccharides adsorb bile acid in the small intestine, allowing bile acid to be excreted together with the feces. The excretion of bile acid promotes the conversion of cholesterol in the liver to bile acid to maintain a certain balance of bile acid and cholesterol in the body, thereby reducing It can reduce the accumulation of cholesterol. Dietary fiber can also reduce the synthesis of very low-density lipoprotein and prevent atherosclerosis. Practice has proved that adding gum in food has a better flavor and has a significant effect on patients with high cholesterol.
High-fiber foods have a low calorific value, and have a strong sense of satiety and delay gastric emptying. However, viscous sugar gums and gums have the characteristics of forming jelly, which can delay the diffusion and absorption of nutrients. Inhibit the absorption of glucose in the small intestine. These polysaccharides also delay the disappearance of insulin in the blood, reduce the amount of free fatty acids in the blood and increase the activity of glucose metabolizing enzymes. Therefore, high-fiber foods help prevent the sharp rise in blood sugar after meals, treat diabetes and Prevent obesity.
Ⅲ. The application status of various dietary fiber products in food processing
3. 1 Bran
When the grain is milled and processed into flour, the bran and germ are separated from the endosperm. Then the bran is improved by degreasing and enzymatic inactivation and reducing the particle size.
3. 1. 1 wheat bran
Wheat bran is a high concentration of insoluble fiber source (about 45%). Its flavor and color vary according to the source. Wheat is the most widely used in baked goods and fast food cereals, and can be used as flour in bread Substitutes, the maximum amount can be as high as about 71%. If the amount in the dough exceeds the above amount, you need to change the bread processing method, because the bran dilution weakens the gluten in the bread, thereby reducing the technological properties of the dough . Applications in other bakery products include biscuits, muffins, cakes and pizzas. Wheat bran has always been widely used as the most common fast food grain enhancer, but now, its position in food production is affected by oat bran. A strong challenge.
3. 1. 2 oat bran
The oat bran made from hulled oats contains 22%-30% cellulose, half of which is soluble fiber, and most of these soluble fibers are hemicellulose. It has high water absorption, and its The purified ingredients can obtain 80% to 90% of dietary fiber. It was originally used as an ingredient in hot and cold fast food cereals, but now it has been successfully developed to use oat bran alone, which is formed and dried until the moisture does not exceed 10% ready-to-eat cereals. Recently, foreign countries are studying the use of oat bran to replace 10% to 15% of the flour in bread recipes to produce bread. Biscuits, crisp breads, crackers and baked fast foods containing oat bran are already on the market abroad and are expected There is further development in the field of baked goods.
3. 1. 3 corn bran
Corn bran is a high-concentration fiber source, where the fiber content is 90%, the color is brown, and the smell is very light. Therefore, it is used in high-fiber low-calorie fast food, bread, cereals, health products, processed meat, batter, It has been used in dough, wafers and biscuits. The addition amount in processed meat is 2% to 5%, in dough is 11%, and in fast food cereals is 30% to 40%.
3. 1. 4 soybean hulls
A typical soybean hull contains 70% of dietary fiber, so it is used in foods such as bread, cakes, biscuits, and fast food.
3. 2 other plant fiber
3. 2. 1 sugar beet fiber
Sugar beet fiber that can be made into flakes or powder is white with a very light odor and contains 75% dietary fiber, of which the proportion of soluble fiber is relatively high (about 23% pectin). Dietary fiber products made from sugar beet It can be used for bread, batter, cakes, biscuits, fast food, pre-filled foods, crumbled snack mixes, dough and meat products, and cereal foods. The addition amount is 5% to 10%. Sugar beet fiber can also be added to soup 1%～2%, when the fiber particle size is less than 10Lm, it can also be used in chocolate.
3. 2. 2 pea fiber
There are two forms of pea fiber. One product is made from pea shells, with a dietary fiber content of 75% to 80%, a lighter color and a lighter odor.
The other product is made from hulled peas. This product contains a higher content of functional white powder fiber components, of which the dietary fiber content is 47%. The first product is mainly used to increase the fiber content in white bread. The second product can combine with water and make low-fat sausages and pies have a lipid structure. Pea fiber products can also be used as thickeners for sauces and condiments, and they are also widely used in dairy products. potential.
3. 2. 3 Other
Other plant fiber sources that can be used for food manufacturing include tomatoes, potatoes, cabbage (cabbage), broad beans, pods, and root plants.
3. 3 Colloid
3. 3. 1 seaweed
The fiber content of red seaweed extract is 15% to 75%. The mature carrageenan exists in the form of K granules, K particles and G particles. Their reactivity with protein can stabilize and improve the structure of food, especially for dairy products. And meat products. The brine around the canned luncheon meat is gelatinous, and ice cream and other dairy snacks (especially ready-to-eat) have been emulsified and stabilized. Cocoa-flavored suspension milk is added to the milk. K particles Carrageenan will replace some casein in cheese. Carrageenan in the form of non-gel K particles can replace some fats in condiments. Alginates are derived from brown seaweed. Foods use its reactivity with calcium to produce stickiness.
- Fructo Oligosaccharide
- Malt Oligosaccharide