Dietary fiber is generally regarded as a type of compound that cannot be digested by human digestive enzymes, and is mainly composed of edible plant cell wall residues (cellulose, hemicellulose, lignin, etc.) and related substances associated with it. According to its solubility, it can be divided into water-soluble dietary fiber and insoluble dietary fiber. In contrast, water-soluble dietary fiber is widely used because of its good processing properties and better physiological functions. Common water-soluble dietary fibers mainly include: inulin, polydextrose, resistant starch, chitosan, oat β-glucan, guar gum, sodium alginate, fungal polysaccharides, etc., some of which are natural preparations and some are synthetic , Semi-synthetic, but regardless of the preparation process, their unique properties have been praised by people. In particular, polydextrose, inulin, and resistant starch have become the most popular high-quality water-soluble dietary fibers.

At present, there are six main types of dietary fiber used at home and abroad: cereals, beans, microbial polysaccharides and other natural fibers and synthetic and semi-synthetic fibers. There are more than 30 varieties, of which more than 10 are actually used in production. There are 6 kinds of more popular in the market, including polydextrose, soybean dietary fiber, and oat dietary fiber. Among them, the United States, Britain, Germany, France, and Japan have formed a certain scale of production and have a certain market share in the food market. In addition, the United States has specialized institutions and large companies that have developed and researched dietary fiber that are manufacturing and selling various dietary fiber products. The research and production of China's dietary fiber started a little later, but there is currently a certain scale of production. Due to the advantages of raw materials and production costs, my country is gradually becoming the world's largest supply base of dietary fiber, and its products are sold to the United States, Japan, South Korea and other countries and regions. In particular, the quality of products such as polydextrose syrup, polydextrose powder and soybean dietary fiber has reached the international level and has a certain market share in the international market, providing abundant resources for the development of dietary fiber foods.

Ⅰ. Interpretation of the concept of dietary fiber

Dietary fiber is a carbohydrate that cannot be digested by the human body. It can be divided into soluble dietary fiber and non-soluble dietary fiber. The former includes partial hemicellulose, pectin and gums, and the latter includes cellulose and lignin.

Another way is to define dietary fiber as two types. One is to define dietary fiber as the remnants of undigested plant cells in the digestive system of mammals from a physiological perspective, including cellulose, hemicellulose, pectin, Resistant starch and lignin, etc.; the other is to chemically define dietary fiber as plant non-starch polysaccharides plus lignin.

Ⅱ. Efficacy and application of dietary fiber

There are different varieties of dietary fiber, but their common advantages are their obvious physiological effects, mainly:

1. Improve digestion, improve gastrointestinal comfort, and prevent constipation

Dietary fiber cannot be digested and absorbed in the stomach and small intestine, so it can stably pass through the upper digestive tract to the large intestine and is fermented by intestinal microorganisms. This physiological function can effectively improve intestinal function, such as promoting bowel movements, alleviating constipation, and improving gastrointestinal comfort.

2. Prebiotics, bifidus factors

After dietary fiber, especially soluble dietary fiber, enters the large intestine because it is not digested, it is selectively absorbed and utilized by beneficial bacteria in the intestine, such as bifidobacteria and lactobacilli, which promotes the proliferation of beneficial bacteria, regulates the balance of intestinal flora, and also It has health effects such as lowering the pH in the intestines and facilitating the absorption of minerals, which fully reflects the role of prebiotics.

3. Alternatives to low-energy fat and sugar

Because dietary fiber is not digested and absorbed by the human upper digestive tract, it generates less energy. The "Food Nutrition Labelling Regulations" specifies that the average energy of dietary fiber is 8kJ/g (2kcal/g), which is about half of the energy of starch and sucrose. Some water-soluble dietary fiber has lower energy, such as polydextrose energy is 4.18kJ/g (1kcal/g), inulin is 1-1.3kcal/g. Some high-quality dietary fibers are also natural oil substitutes, and can still maintain the original texture and taste without adding or adding less fat.

4. Prevent colon and rectal cancer

The occurrence of these two kinds of cancers is mainly related to the long stay of carcinogens in the intestine and long-term contact with the intestinal wall. Increasing the fiber content in the diet reduces the concentration of carcinogens. In addition, dietary fiber has the effect of stimulating intestinal peristalsis. The contact time of carcinogens with the intestinal wall is greatly shortened. Scholars agree that a long-term diet based on high animal protein, coupled with insufficient intake of fiber, is an important cause of these two types of cancer.

5. Conducive to weight loss

The general obese people are mostly related to the increase in heat intake in food or the decrease in physical activity. Increasing the dietary fiber content in the diet can reduce the intake of heat energy, and the digestion and absorption of nutrients in the intestinal tract will also be reduced, and ultimately the body fat will be consumed for weight loss.

6. Lower blood lipids and prevent coronary heart disease

As some components in dietary fiber can bind cholesterol if glue, lignin can bind bile acid and make it directly excreted from feces, thereby consuming cholesterol in the body to supplement the cholesterol consumed in bile. As a result, cholesterol is lowered, which has the effect of preventing coronary heart disease.

7. Improve the symptoms of diabetes

The pectin in the dietary fiber can extend the residence time of food in the intestines, reduce the rate of glucose absorption, so that blood sugar will not rise sharply after a meal, which is beneficial to the improvement of diabetes. In recent years, studies by scholars have shown that dietary fiber has the effect of lowering blood sugar. Experiments have shown that 26 grams of edible corn bran (91.2% fiber) or soybean hulls (86.7% fiber) are added to the diet every day. As a result, after 2830 days, glucose tolerance improved significantly. Therefore, the long-term increase of dietary fiber in the diabetic diet can reduce the amount of insulin required and control the metabolism after a meal. It should be used as an auxiliary measure for the treatment of diabetes.

8. Prevention and treatment of gallstones

The formation of gallstones is related to the high content of cholesterol in bile. Dietary fiber can combine with cholesterol to promote the secretion and circulation of bile. It can prevent the formation of gallstones. Some people add 20-30 grams of grain fiber to the patient every day. After one month, the gallstones can be found to shrink, which is related to the smooth flow of bile.

Ⅲ. Foods rich in dietary fiber and their effects

Cucumber: Crisp and delicious, with heat-clearing, thirst-quenching and diuretic effects. The cellulose contained in it can promote the excretion of food waste from the intestines, thereby reducing the absorption of cholesterol, and can have the effect of losing weight and adjusting lipid metabolism.

Shiitake Mushroom: It has the functions of digestion, fat removal and blood pressure reduction. The cellulose contained in it can promote gastrointestinal peristalsis, prevent constipation, and reduce the absorption of cholesterol in the intestine. Shiitake mushrooms also contain nucleic acid substances such as purines, which can promote the decomposition of cholesterol. Regular consumption of shiitake mushrooms can lower cholesterol and triglycerides.

Sweet potato: Nutrition studies have found that moderate consumption of sweet potato can prevent lipid deposition in the cardiovascular system, prevent atherosclerosis, reduce subcutaneous fat, and avoid excessive obesity. It has a strong effect of lowering blood cholesterol, maintaining blood acid-base balance, delaying aging, preventing cancer and anti-cancer. Sweet potato is rich in dietary fiber and colloids and other defecation substances, which can be described as "intestinal scavenger".

Oatmeal: has the effect of lowering cholesterol and blood lipid. Because oatmeal contains rich soluble dietary fiber that other grains do not have, this fiber is easily absorbed by the human body and has low calories. It is not only good for weight loss, but also suitable for dietary needs of people with heart disease, high blood pressure and diabetes.

Corn: rich in calcium, phosphorus, magnesium, iron, selenium and vitamins A, B1, B2, B6, E, carotene, etc., and also rich in fiber. Regular consumption of corn can lower cholesterol and soften blood vessels and has an adjuvant therapeutic effect on cholecystitis, gallstones and diabetes.

Ⅳ. Daily intake standards of dietary fiber

The daily intake of dietary fiber recommended by relevant international organizations: The American Anti-Cancer Association recommends a standard of 30-40 grams per person per day, and the European Community Food Science Committee recommends a standard of 30 grams per person per day.

Dietary fiber plays an important role in promoting good digestion and excretion of solid waste. Supplementing cellulose in an appropriate amount can increase and soften the food in the intestine, and promote intestinal peristalsis, thus speeding up bowel movement, preventing constipation and reducing the risk of bowel cancer.

In addition, cellulose can also regulate blood sugar and help prevent diabetes. It can also reduce the absorption of fat in the digestion process, thereby reducing the level of cholesterol and triglycerides in the blood, and preventing high blood pressure and cardiovascular and cerebrovascular diseases. Regular consumption of apple collagen can prevent and inhibit various diseases of the human body such as cardiovascular disease, gastrointestinal disease, respiratory disease, metabolic disease and tumor. Secondly, as a kind of natural macromolecule water-soluble dietary fiber, apple collagen has the function of strongly adsorbing and eliminating the body's "radiation (positively charged substance)", and it is an essential nutrient balance for the human body. It has a unique molecular structure and physiological characteristics that cannot be directly digested by the human body, so it can naturally absorb and discharge harmful substances that are difficult to self-metabolize such as "toxins", "negative nutrients", "heavy metals" and "free radicals" in the human body. In vitro, so as to achieve nutritional balance.

Dietary fiber is a food nutrient that is generally difficult to digest. It mainly comes from the cell walls of plants, including cellulose, hemicellulose, resin, pectin, and lignin.

Fiber can be divided into two basic types when dissolved in water: water-soluble fiber and non-water-soluble fiber. Water-soluble fibers include resin, pectin and some semi-fibers. Common foods such as barley, beans, carrots, citrus, flax, oats and oat bran are rich in water-soluble fiber. Water-soluble fiber can slow down digestion and excrete cholesterol most quickly, so it can increase blood sugar in the blood. And cholesterol control beyond the ideal level, can also help diabetic patients to reduce insulin and triglycerides.

Insoluble fibers include cellulose, lignin and some semi-fibers, as well as wheat bran, corn bran, celery, peel and root vegetables from food. Insoluble fiber can reduce the risk of intestinal cancer. It can also prevent constipation and diverticulitis by absorbing toxic substances in food, and reduce the toxins excreted by bacteria in the digestive tract. Most plants contain both water-soluble and water-insoluble fiber, so a balanced intake of water-soluble and water-insoluble fiber in the diet can achieve different benefits.

Ⅴ. Benefits of dietary fiber:

◇Keep the digestive system healthy

◇Strengthen the immune system

◇Lower cholesterol and high blood pressure

◇Reduce insulin and triglycerides

◇Laxative, diuretic, clear intestines and stomach

◇Prevent cardiovascular disease, cancer, diabetes and other diseases

◇Balance the hormones in the body and reduce hormone-related cancers

Dietary fiber is indispensable for a healthy diet. Fiber plays an essential role in maintaining a healthy digestive system. At the same time, adequate intake of fiber can also prevent cardiovascular disease, cancer, diabetes and other diseases. Fiber can clean the digestive wall and enhance digestion. Fiber can also dilute and accelerate the removal of carcinogens and toxic substances from food, protect the fragile digestive tract and prevent colon cancer. Fiber can slow down digestion and excrete cholesterol most quickly, so blood sugar and cholesterol in the blood can be controlled at the optimal level.