Polydextrose is a low-calorie, low glycemic index special carbohydrate with water-soluble dietary fiber and prebiotics.

It is made of naturally occurring glucose and a small amount of sorbitol and citric acid by high temperature melt polycondensation, which is a polysaccharide composed of randomly cross-linked glucose.

Polydextrose, as one of the dietary fibers with good effect and performance, has been rapidly developed in recent years, approved for use in more than 50 countries, and has been more and more widely used in many foods, beverages and health foods.

Physicochemical properties of polydextrose

1.1 Solubility

Polydextrose is easily soluble in water, the solubility is 70% at 25°C, heating can promote its dissolution.

1.2 Viscosity

The viscosity of polydextrose solution decreases with the increase of temperature and increases with the increase of concentration, similar to common sugar, under the same concentration, the viscosity of polydextrose solution is slightly higher than common sugar.

1.3 Stability

Polydextrose can be stored stably for 90 days under 60℃, and it does not react with acid and alkali under high temperature of 200℃, but its hygroscopicity is strong, so it should be stored in dry environment.

Modified polydextrose will lose water when exposed to air, when the relative humidity is 75%, the concentration of the solution will be concentrated to 80%; the relative humidity is 52%, it can be concentrated to 90%.

1.4 Moisturizing

Polydextrose is a good food moisturizer, high ambient temperatures can be fully absorbed to control temperature changes. At the same time it can also control the water activity of the solution, when the water activity is greater than 60%, it can effectively reduce, because it has a highly branched structure and will not crystallize, so the effect is better than the small molecules such as common sugar and sorbitol.

1.5 Flavor

Polydextrose has no sweet taste and can be used with high sweetness and low calorie sweeteners to make low calorie food. When its concentration is high, there will be bad flavor, which can be eliminated by reducing the dosage, adding flavorings or flavor modifiers.

1.6 Melt and dissolve property

Polydextrose powder starts to dissolve at 130℃, after cooling, it is transparent glassy substance, similar to the brittle structure of hard candy, but it will not form crystals.

1.7 Corrected freezing point

The freezing point of polydextrose is higher than that of the same concentration of confectioner’s sugar solution, and the freezing point of polydextrose solution neutralized with KOH is much lower than that of the unneutralized one. The lower the freezing point value, the harder the texture of the food product, which is suitable for popsicles and certain desserts. When using high sweetness sweeteners to make low-calorie frozen desserts, polydextrose can be added to adjust the matrix of the product, compensate for the loss of matrix due to the reduction of granulated sugar, and improve the undesirable texture.

Physiological Properties of Polydextrose

2.1 Low calorie

Polydextrose has a complex molecular structure with many kinds of sugar-bitter bonds, which is difficult to be degraded by microorganisms, so its calorie is only about 1 kcal/g.

2.2 Regulation of intestinal tract

Polydextrose can be utilized by bacteria in the intestinal tract to produce carbon dioxide, methane and SOFA (volatile fatty acid) by fermentation.

The isotope tracer method was used to measure SCFA, and it was found that its main components are butyrate and propionate. Colon bacteria can use butyrate to regulate their intestinal environment and inhibit the formation of cancer cells. Propionate can inhibit cholesterol synthesis in the liver, improve glucose metabolism in the liver, stimulate glycolysis, and inhibit gluconeogenesis.

At the same time, the pH of the intestinal contents decreased along with the production of SOFA. After 150 min of polydextrose intake, the pH of duodenal fluid decreased from 7.24±0.45 to 6.44±0.3 5, indicating that polydextrose can promote the growth of beneficial bacteria such as bifidobacteria and inhibit harmful bacteria, thus improving the composition of the intestinal microflora.

2.3 Lowering triglycerides and cholesterol

Polydextrose prevents triglycerides and cholesterol from entering the lymphatic capillaries. At the same time, its products degraded by intestinal microorganisms can also inhibit cholesterol synthesis, adsorb cholesterol metabolite bile acids and excrete them out of the body, so as to reduce cholesterol content in the body, and prevent the shape of gallstones.

It has been reported that chocolate with added polydextrose has a significant effect on lowering serum triglycerides, and the effect is even better when used in conjunction with lactitol.

2.4 Help control and weight loss

Polydextrose can form a film on the gastrointestinal wall, wrapping the fat in the food, restricting the absorption of fat in the digestive tract, and promoting the excretion of lipids, thus reducing the accumulation of fat, and achieving the efficacy of preventing obesity. It can also inhibit the appetite, reduce the eating of obvious, and enhance the sense of satiety.

2.5 Promote calcium absorption

Studies have shown that ingestion of polydextrose ( 50g/kg, 21 d ) can increase the absorption of calcium. Japan Hitoshi Mineo et al. found that with the increase of polydextrose concentration in the range of 0-100mmol/L, the absorption of calcium in the jejunum, ileum, cecum and small intestine of mice showed a significant increasing trend, while the absorption of calcium in the human intestine was not significant.

2.6 Detoxification and enhancement of immunity

Polydextrose can reduce the activity of α-benzopyrene hydroxylase, reduce the harm of benzo(a)pyrene on the digestive system, enhance the body’s clearance of PCBs, and at the same time, it can promote the body’s dioxin in the form of feces out of the body.

Ouk fed mice with polydextrose at 3% of daily food intake and found that the amount of feces increased, the passage time of feces in intestine decreased, and the temperature of feces increased.Tomlin and Read also found that polydextrose increased the amount of fecal excretion and softened it.

2.7 Hypoglycemia

Polydextrose can improve the receptivity of terminal tissues to insulin, reduce the requirement of insulin, inhibit the secretion of insulin, hinder the absorption of sugar, and polydextrose itself will not be digested and absorbed, so as to achieve the purpose of lowering blood sugar.

2.8 Non-caries

Polydextrose will not be utilized and fermented by microorganisms in the mouth, so it has no damage to teeth.

Application in food

Polydextrose is added to food as a filler, antifreeze, cryoprotectant, anti-aging agent, dietary fiber, prebiotic ingredient, preservative and freshness preservation, and osmolality increase to provide the necessary volume, but also to give realistic texture and taste, and to ensure a high quality of fiber source.

Not only can they be consumed by normal people who wish to consume low calories and maintain good health, but also by special groups such as diabetics, and it is expected that the use of polydextrose will increase in the future.

3.1 Applications in health food

3.1.1 Application in food for diabetics

In addition to the medication required for the treatment of diabetes mellitus, it mainly relies on dietary control. Therefore, proper adjustment of dietary structure is the most important method to prevent and control diabetes. Polydextrose can slow down the adsorption of glucose, and the sugar in the blood will increase slowly, and if insulin is slightly insufficient, it will not cause an increase in blood glucose concentration immediately. In addition, polydextrose also has the effect of inhibiting the secretion of glucagon, which can reduce the blood sugar level of diabetic patients.

3.1.2 Application in food for constipated people

After taking polydextrose, it can promote the growth and reproduction of beneficial bacteria such as intestinal bifidobacteria, lactobacillus, etc. Meanwhile, it produces a large number of short-chain fatty acids, such as acetic acid, acetic acid, folic acid and lactic acid, which can change the intestinal pH value and improve the reproduction environment of the beneficial bacterial flora, thus accelerating the intestinal peristalsis to make the feces discharged smoothly.

3.1.3 Application in infant food

Infants and young children weaned from the body bifidobacteria plummet, resulting in diarrhea and anorexia, developmental delay, reduced utilization of nutrients; consumption of food containing polydextrose can improve the utilization of nutrients and promote the absorption of calcium, iron, zinc and other trace elements.

3.2 Application in common food

3.2.1 Beverage

Glucose has excellent characteristics such as good water solubility, low pH and high stability under heating conditions, stability in shelf life, no loss of fiber, etc. It is widely used in beverage products (including solid beverages) with no bad taste, good color and transparency, and can enhance the taste of sugar-free or low-sugar beverages. This drink can quench thirst, supplemental water, but also to provide the body with the required dietary fiber, in Europe and the United States, Japan and other countries are very popular. Such as Japan’s Coca-Cola Company produced mineral water containing dietary fiber, Western Europe, the United States, high-fiber orange juice, high-fiber tea, the domestic Huiyuan development of high-fiber juice, Sanyuan Dairy’s high-fiber milk and so on.

3.2.2 Candy

Polydextrose is also a good ingredient for sugar-free candy with good tolerance. High water solubility and high viscosity, to ensure good chewing of hard candy and gummy candy; can prevent than crystallization, especially the use of sugar alcohols candy; non-cariogenic, suitable for dental candy. Adding polydextrose sucrose candy, play a role in strengthening fiber, prebiotics, reduce sucrose, but also reduce calories or reduce the total glucose production value.

3.2.3 Dairy products

Polydextrose has excellent properties such as good stability at low pH, no sweetness and neutral taste, high viscosity, etc. Therefore, it can be applied to low-fat and fat-free dairy products, which not only improves the taste of dairy products, but also improves the stability of dairy products during the shelf-life, and does not react with any of the components in the physicochemical reactions unfavorable to the human body. In addition, adding dietary fiber to dairy products can also meet the body’s demand for dietary fiber. This type of product is very popular among consumers in Europe and the United States.

3.2.4 Frozen desserts

Polydextrose can be used in many frozen desserts instead of glucose syrup. Because of its water retention, inhibit the formation of ice crystals, hydration texture, puffiness, etc. are similar to sucrose, its organizational structure does not affect, but also extend the shelf life of the product. When mixed with high-intensity sweeteners such as aspartame, the same flavor quality as traditional frozen desserts can be achieved. In low-fat ice cream, the addition of polydextrose and the use of maltodextrin can increase the creaminess and creaminess of the ice cream, while the impact on the yield, shelf life and price of the ice cream is minimal.

3.2.5 Bakery products

Polydextrose is very heat-resistant, combining various excellent properties ideally in the baking production process. As an effective sucrose substitute, it can slow down the aging of starch, maintain moisture, provide good texture and taste, and is especially suitable for processing low-sugar and low-fat baked foods. When added to cookies, polydextrose can still obtain similar texture and taste as traditional products. When added to bread, it can also act as an anti-aging agent.

3.2.6 Meat products

Used in chicken nuggets, it can reduce the loss of moisture during cooking, while the surface coating remains crispy; in frozen surimi products, it acts as a cryoprotectant without providing sweetness and improves flavor and texture; in meat stuffing and emulsified sausages, it can replace part of the fat without affecting the taste.