Overview of Soluble Dietary Fiber
Dietary fiber (DF) is usually regarded as a class of compounds 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 bound to them. According to its solubility, it can be divided into water-soluble dietary fiber and insoluble dietary fiber.
Common water-soluble dietary fibers include: inulin, dextran, resistant starch, chitosan, oat β-glucan, guar gum, sodium alginate, fungal polysaccharides, etc. Barley, beans, carrots, citrus, flax, oats, and oat bran are all rich in water-soluble fibers in common foods.
In contrast, water-soluble dietary fiber because of its good processing performance and better physiological functions, in recent years in food processing as a thickener, swelling agent, formulation aids and fillers, widely used in low-energy food and functional food production and development, water-based dietary fiber related food has a huge space for development, the market has a bright future.
Physicochemical properties and functions of water-soluble dietary fiber
1.High water retention and expansion and function
There are many hydrophilic genes in the structure of water-soluble dietary fiber, which has strong water absorption, high water retention and high expansion. It can increase the volume of feces and the speed of defecation, reduce the pressure in the rectum and the urinary system, relieve the symptoms of urinary diseases such as cystitis, bladder stones, kidney stones, etc., and enable the toxins to be rapidly discharged from the body, preventing constipation and rectal cancer.
Dietary fiber with high water retention and high expansion properties to delay gastric emptying, so that the human stomach to produce a sense of satiety to reduce food intake, is conducive to preventing obesity and weight loss.
2. Adsorption and boiling cooperation and function
There are many active genes on the surface of water-soluble dietary fiber, which can adsorb organic molecules such as cholesterol and bile acids, inhibit the increase of total cholesterol concentration, reduce the synthesis and absorption of cholesterol and salts, and reduce the cholesterol in serum and liver, thus preventing coronary arteriosclerosis and cardiovascular diseases.
3. Fermentation and adjustment of intestinal microbiota function
Soluble dietary fiber can be fermented into acetic acid, lactic acid and other organic acids by beneficial bacteria in the large intestine, which can reduce intestinal pH, promote the growth of beneficial bifidobacteria in the intestines, prevent intestinal mucosa from shrinking, and maintain intestinal microbial balance and health. The organic acid produced by fermentation can accelerate the peristalsis and digestion of food in the gastrointestinal tract, promote the excretion of feces, prevent the toxic substances in the intestines from stimulating the intestinal wall and the toxins from staying for too long, and prevent colon cancer.
4. Non-energy filling and fat prevention function
Soluble dietary fiber binds water (water absorption and holding) expansion after the volume becomes large, in the intestinal tract will play the role of filler, easy to cause a sense of satiety, at the same time, due to dietary fiber will also affect the use of carbohydrates and other ingredients in the intestinal tract, absorption and digestion, but also make it difficult for people to produce a sense of hunger. So dietary fiber is very beneficial to the prevention of obesity.
5. Solubility and viscosity and their functions
Soluble dietary fiber has viscosity and has a great influence on food viscosity. Due to the increase of viscosity, the intestinal contents and intestinal mucosa contact is reduced, thus slowing down the rate of absorption, which can make diabetic patients become stable blood glucose level after eating, promote the pancreas to discharge insulin, which is conducive to the supply and metabolism of sugar. Increasing dietary fiber in food can improve the peripheral tissue’s insulin receptivity, achieving regulation and control of blood glucose levels in diabetics.
Application of water-soluble dietary fiber in foods
Water-soluble dietary fiber, as a new type of dietary fiber and thickener, swelling agent, formulation aid, filler, etc., is mainly used in low-energy, high-fiber and other functional foods. In low-energy foods, water-soluble dietary fiber can partially or completely replace sugar and fat, which can maintain the original flavor and texture of the food while reducing the energy of the food and bring a satisfactory taste. In addition to health care products, water-soluble dietary fiber has a wide range of applications in beverages, dairy products, confectionery, bakery and other food fields due to its good solubility, stability, calm taste and other characteristics.
1. The application of water-soluble dietary fiber in health foods
(1) Application in health food for diabetics
Diabetes mellitus is a disease caused by absolute or relative insulin insufficiency, which is manifested as metabolic disorders of carbohydrates, fats, proteins, water and electrolytes. Water-soluble dietary fiber can delay gastric emptying and form a kind of mucous membrane in the stomach and intestines, which slows down the digestion and absorption process of food nutrients. In this way, the sugar in the blood can only increase slowly, or insulin is slightly insufficient, but also does not immediately cause an increase in blood glucose concentration.
At the same time, water-soluble dietary fiber also has the role of inhibiting glucagon secretion. Studies have shown that: after adding dietary fiber to the diet, fasting blood glucose from (9.84 ± 3.51) mmol / L down to (6.82 ± 2.65) mmol / L, 2h postprandial blood glucose from (1.3.08 ± 5.12) mmol / L down to 10.57 ± 4.64 mmol / L, P < 0.01. The development of products such as: water-soluble dietary fiber softgels, Developed products such as: water-soluble dietary fiber soft capsule, fructose syrup, etc.
(2) Application of health food for constipated people
Water-soluble dietary fiber is widely used to regulate microecological balance, laxative health food, water-soluble dietary fiber is taken to promote the intestinal bifidobacteria, lactobacillus and other beneficial bacteria, and at the same time, produce a large number of short-chain fatty acids, such as acetic acid, acetic acid, folic acid and lactic acid, to change the intestinal pH, to improve the reproduction environment of the beneficial bacterial groups, thereby accelerating intestinal peristalsis, so that the fecal matter smoothly discharged.
2. Application of water-soluble dietary fiber in dairy products
(1) Application of water-soluble dietary fiber in milk powder
Water-soluble dietary fiber is more suitable to be added in milk powder to produce infant formula and milk powder for the middle-aged and elderly. The digestive tract function of infants and middle-aged and elderly people is not very good, and it is easy to lack of calcium. Water-soluble dietary fiber has the effect of laxative, as well as lowering blood lipids, lowering blood sugar, promoting the absorption of minerals and other effects. Water-soluble dietary fiber milk powder in water-soluble dietary fiber add 5% to 10%, add the method is water-soluble dietary fiber in milk concentrate homogenization before adding, other processes remain unchanged; or milk powder directly after the addition of mixing, stirring can be.
(2) Application of water-soluble dietary fiber in fermented yogurt
Yogurt is one of the fastest growing dairy products and one of the most popular dairy drinks in the walk-and-drink type of healthy dairy products. In recent years, high-fiber yogurt products have become very popular. High-fiber yogurt products are formulated as follows: 80% high quality fresh milk, 3% whole milk powder, 3% fruit glucose syrup (71%), 2% sucrose, 10% water, 6% water-soluble dietary fiber, 2.5% leavening agent, stabilizer 0.2%.
(3) Application of water-soluble dietary fiber in flavored milk beverages
Flavored milk drink has appeared in the domestic and foreign markets for many years, because it has a milky flavor in addition to the fruit flavor, the fusion of the two flavors to make the flavor of the milk drink unique flavor, coupled with a certain degree of nutrition, so it is welcomed by the majority of consumers, especially by the children and young women’s welcome. The addition of water-soluble dietary fiber to flavored milk beverages can largely increase the nutritional and health functions of milk beverages.
The formula design (chocolate flavored milk drink as an example) is as follows: raw milk (milk powder) 80% to 90% (9% to 12%), fructose syrup (71%) 6% to 8%, sucrose 4% to 6%, water-soluble dietary fiber 6% to 8%, cocoa powder 1% to 2%, stabilizers 0.2%, the right amount of vanillin, the right amount of flavors, the right amount of coloring.
(4) Application of water-soluble dietary fiber in lactic acid bacteria beverage
Lactobacillus beverages, also known as fermented acidic milk beverages, usually cow’s milk or milk powder, plant protein milk (powder), fruit and vegetable juices, sugar as raw materials, with or without the addition of food additives and auxiliaries, after sterilization, cooling, inoculation of lactobacillus fermentation agent culture and fermentation, and then by dilution of the active (non-pasteurized) or inactive (sterilized) beverages made. Although the active bacteria drinks contain a certain amount of beneficial bacteria, but after the human digestive tract, the beneficial bacteria left little, its nutritional health functions greatly reduced. The nutritional health function of inactive bacteria drinks is even more limited.
How to improve the nutritional and functional components of lactic acid bacteria drinks is a problem in front of every dairy beverage manufacturer. Water-soluble dietary fiber with its superior health effects for the majority of dairy beverage manufacturers to provide a good choice, bringing new hope.
Formula design: 30% yogurt, fruit glucose syrup (71%) 8%, 2% sucrose, 6% water-soluble dietary fiber, pectin 0.4%, fruit juice (6%) 45%, lactic acid 0.1%, flavor 0.1%, water 47.4%.
3. The application of water-soluble dietary fiber in beverages
Dietary fiber beverages are very popular in the West, functional beverages. It can quench thirst, supplement water, but also provide the body with the required dietary fiber. These products, especially water-soluble dietary fiber in Europe and the United States and Japan and other developed countries are more popular. Such as Japan’s Coca-Cola Company produced mineral water containing dietary fiber, prevalent in Japan; in addition, Western European countries and the United States of high-fiber orange juice, high-fiber tea is also very common; the current domestic Huiyuan company developed and produced high-fiber juice, Beijing Sanyuan Dairy launched a high-fiber milk.
Long-term drinking can make the intestinal tract smooth, to prevent constipation, and can reduce cholesterol, regulate blood lipids, blood sugar, help to lose weight, especially for middle-aged and elderly people, diabetic patients and obese people to drink. In the beverage application, the characteristics are as follows: A, drinking drinks with water-soluble dietary fiber, can make the drinker absorb the nutrients at the same time, enhance the sense of satiety, reduce the intake of caloric substances, long-term consumption can significantly help control weight loss, especially suitable for young and middle-aged obese people drink; B, in the beverage after the use of water-soluble dietary fiber, the beverage can be used to make the other particles uniformly distributed solution, not easy to produce sedimentation and layering phenomenon. Layering phenomenon is not easy to produce precipitation and layering.
4. Application in baby food
Infants and young children, especially after weaning, have a sudden decrease of bifidobacteria in the body, which leads to diarrhea and anorexia, developmental delay and lower utilization rate of nutrients. Consumption of water-soluble dietary fiber food can improve the utilization rate of nutrients and promote the absorption of calcium, iron, zinc and other trace elements.
5. Application in candy
The future development of the confectionery industry gradually tends to low-sugar, low-fat, towards the direction of both delicious and nutritious development. In developed countries, the market share of low-energy confectionery is increasing year by year, showing its strong momentum of monopolizing the whole confectionery market. Water-soluble dietary fiber as a major low-energy food ingredients, in the confectionery market is very useful.
Water-soluble dietary fiber (Polydextrose) can be used in all confectionery formulations as a substitute for glucose syrup and can be used in conjunction with other alternative sweeteners to replace sucrose.
6. Application of water-soluble dietary fiber in meat products
By adding water-soluble dietary fiber into meat products, dietary fiber and protein interact with each other through salt and hydrophobic bonds to form a heat-stable gel, and the complex formed by the interaction of soluble dietary fiber and protein is a new type of gelling body.
Moreover, dietary fiber can absorb flavor substances and prevent the volatilization of flavor substances. In addition, dietary fiber is also an excellent fat substitute, can produce high protein, high dietary fiber, low fat, low salt, low calorie ham sausage with health functions.
7. Water-soluble dietary fiber in the application of pasta products
(1) Application in bread, steamed bread, rice and noodles
Bread has become a worldwide popular food with a large sales volume. In Europe and the United States, dietary fiber is added to most breads to varying degrees, and some studies have shown that the addition of different kinds of dietary fiber can also increase and improve the color of bread. Add dietary fiber in steamed bread, generally add 3% to 6% of the flour is more appropriate. Add dietary fiber can make the dough gluten strengthening, out of the cage buns taste good, have a special flavor.
Add in the rice also has a fluffy and fragrant good taste, the two staple foods generally add dietary fiber will be beneficial to the general public’s health. Add dietary fiber in the noodles, generally appropriate amount of 3% to 6%. But different kinds of fiber effect is different, some added to the strength of raw noodles weakened, can be cooked instead of increasing the strength of the general addition of the processed noodles toughness is good, resistant to cooking and soaking. The key to the noodle adding technology is to master the adding amount and different kinds of dietary fiber.
(2) Application in cookies and pastries
Cookie baking on the flour gluten quality requirements are very low, but also to facilitate a larger proportion of dietary fiber added, so it is conducive to the production of a variety of health care cookies mainly fiber function. Pastries, on the other hand, contain a lot of water in the production, which will solidify into fluffy products during baking and affect the quality. Water-soluble dietary fiber added to the pastry, can keep the product soft, moist, increase shelf life, extend shelf life.
8. Sports food
Dietary fiber has a high degree of water retention, the relative volume of small, absorbent volume, which produces a volume effect on the intestinal tract, resulting in a sense of satiety, there is a dietary fiber intake can reduce blood glucose values, thereby achieving a slow release of energy, based on the two characteristics of the sports food made in the fitness or participate in sports, before and after the consumption.
9. Frozen food
Increase the dough formation and water retention of products. Adding method: according to the total amount of traps about 1%, add dietary fiber weight 3-5 times the weight of water, and the traps together with the mix can be.
10. In sauce products
Good water absorption and water retention, increase the juice viscosity of the product, improve the sensory properties, homogeneous, non-delamination.
The raw and auxiliary materials for the production of cookies mainly include flour, sugar, oil, starch, yeast, salt and so on. The quality of raw and auxiliary materials and the method and effect of pretreatment directly affect the quality of products.
Flour
(I) Ductile cookies
Production of tough cookies wheat flour, it is appropriate to use medium gluten elasticity, good extensibility, low gluten content of the flour, generally to wet gluten content of 21% to 28% is appropriate. If the gluten content is high, strong gluten, the production of cookies is easy to shrink, deformation, taste burgundy, surface blistering, therefore, the gluten content is too high wheat flour, it is appropriate to add an appropriate amount of starch to dilute, adjust; if the gluten content is too low, weak gluten, cookies will be cracked, easy to break.
(B) sweet and crispy cookies
The production of sweet and crispy cookies flour to be soft wheat processing of weak gluten flour, the requirements of wet gluten content of 19% to 22%, if the gluten is too strong, still need to be adjusted with starch.
(iii) Fermented cookies
Fermented cookies generally use the second fermentation production technology, the two feeding flour selection also has certain differences, in the first dough fermentation, due to the fermentation time is longer, in order to make the dough can withstand a longer period of fermentation without leading to excessive reduction in the elasticity of the dough, should be used in the wet gluten content of about 30%, glutenous flour; the second fermentation of the dough, the time is shorter, it is desirable to use the wet gluten content of 24% to 26%, slightly weaker gluten content. ～For the second fermentation, when the time is shorter, it is better to use flour with wet gluten content of 24% to 26% and slightly weaker gluten. If the gluten is too low, the cookies appear crispy but not crisp; gluten is too high, the cookies are easy to shrink and deform, the taste is crisp but not crispy.
(D) Wafer cookies
Wafer cookies choose flour to wet gluten content of 23% to 24% of the appropriate. If the gluten is too strong, it is easy to rise in the process of mixing, and the cookies produced are dry and hard and not crisp; on the contrary, if the gluten of the flour is not enough, the cookies produced are easy to break and easy to stick to the mold in the production.
Flour generally needs to be processed before use. First, sifting: not only to remove impurities, but also to ensure that the flour mixed with a certain amount of air, conducive to the crispness of the cookies; the second is the installation of magnets in the sifting system, adsorption of magnetic substances; third, according to the different seasons, changes in temperature, the temperature of the flour should be effectively adjusted. Generally, when the flour is used in winter, it is transported to the workshop in advance to increase the temperature of the flour; in summer, the flour is stored in a ventilated, low-temperature and dry place to facilitate the lowering of the temperature of the flour.
Starch
When the gluten of wheat flour is too high, starch needs to be added to dilute the gluten proteins and reduce the gluten of the dough. The starches often added are wheat starch, corn starch and potato starch. Starch is treated in much the same way as flour before use.
Grease
The production of cookies requires the selection of fats and oils with excellent shortening and high stability, and the requirements for fats and oils vary for different varieties of cookies.
(1) Ductile cookies are produced with less oil, and cream, margarine, refined lard, etc. are commonly used. As tough cookies are usually added during the operation of the sulfite improver can promote the rancidity of fats and oils, it is not suitable for the use of unsaturated fatty acids higher vegetable oils, such as peanut oil, sunflower oil, etc.,.
(2) crisp cookies and sweet shortbread cookies production of large amounts of fat, both to consider the excellent stability of fat, shortening better, but also requires the selection of higher melting point of fat, otherwise it is very easy to cause too high a temperature of the dough or the melting point of the fat is too low leading to an increase in the dispersion of fat, the occurrence of the phenomenon of “go oil”. The most suitable fats for high fat products are margarine and vegetable shortening.
(3) The fats and oils used in the production of fermented cookies require both shortening and stability, especially in terms of shortening, which is more demanding than that of tough cookies. Refined lard shortening is the most favorable for making delicate, crispy fermented cookies. Although vegetable shortening is better in improving the level of cookies, but the fluffiness is a bit poor, so we can use vegetable shortening and good lard to achieve complementary effects.
Yeast Extract
In the production of fermented cookies, the quality of yeast is an important factor in the whole process. If the performance of yeast is not good, it will bring irreparable losses to the production of cookies. Therefore, the quality of yeast should be identified and selected before production.
(1) Pay attention to the date of production, and choose the yeast within the shelf life;
(2) Selection of packaging hard yeast, active dry yeast is often vacuum packaging, if the bag becomes soft, indicating that there is air into the vitality will be greatly reduced;
(3) Pay attention to the choice of yeast type, there are two types of yeast, high sugar type and low sugar type, usually printed on the bag “high sugar type” or “low sugar type”.
Yeast treatment before use: instant active dry yeast can be directly put into the flour for fermentation, but fresh yeast and active dry yeast must be activated before use.