Carrageenan (Carrageenan), also known as carrageenan, carrageenan. Carrageenan from red algae seaweed extract some out of the hydrophilic colloid, and its chemical structure and dehydration by galactose galactose polysaccharides composed of calcium sulfate, potassium, sodium, ammonium salt. As one of sulfate with different forms, can be divided into K-type (Kappa), I type (Iota), L-type(Lambda).
1. Introduction
The use of carrageenan originated hundreds of years ago, in the southern coast of Ireland produced a seaweed known as Irish moss (Irish Moss), now known as the wrinkle wave angle algae (Chondrus crispus), local residents often taken to put it milk sugar boiling, put the cold solidified food. Early 18th century, Irish people have made ​​such a seaweed powder and introduced to the United States, was a company started commercial production, and seaweed powder (sea moss farina) began selling the name, is widely used in milk and a variety of food in. United States began the 19th century factory refined carrageenan, carrageenan to the 1840s in the U.S. industry really developed. Hainan Island, China in 1973, began in carrageenan production.
2. Chemical structure
Sulfate or sulfate of the base of the galactose and 3,6 - dehydrated galactose by α-1, 3 glycosidic bond and the β-1, 4 bond lternating connection is made to connect the D-galactose 1,3 unit C4 with a sulfate on. Molecular weight of 200,000 or more.
3. Colloid chemistry
● Solubility: insoluble in water, but can swell into a plastic block, is not soluble in organic solvents, soluble in hot water into a translucent colloidal solution (above 70 ℃ hot water in the dissolution rate increased;
● Gelling: in the presence of potassium ions can generate heat reversible gel;

● Thickening: the formation of low viscosity at low concentration of the sol, close to the Newtonian fluid, the formation of high-viscosity sol concentration, the non-Newtonian fluids was.
● synergy: and locust bean gum, konjac gum, xanthan gum and other colloidal synergistic effect, can increase the flexibility and water retention gel;
● health value: Carrageenan has the basic characteristics of soluble dietary fiber in vivo degradation of the carrageenan with the formation of soluble fibrin complexes. coliform bacteria can be fermented into CO2, H2, methane, and formic acid, acetic acid,propionic acid and other short-chain fatty acids, as the energy source of probiotics.
4. Applications in food industry
Carrageenan stability, dry powder is not easy to degrade long-term placement. It is in neutral and alkaline solution is also very stable, even heat and will not hydrolysis, but in acidic solution (pH value, especially ≤ 4.0) carrageenan prone to acid hydrolysis, gel strength and viscosity decreased. It is noteworthy that, in neutral conditions, if prolonged heating at high carrageenan also hydrolyzed, resulting in lower gel strength. All types of carrageenan can be dissolved in hot water and hot milk. Soluble in hot water to form a transparent or slightly milky viscous flow of the solution is easy. Carrageenan swelling in cold water can not dissolve. With carrageenan-based nature of the food industry often used as a thickener, gelling agent, suspending agent, emulsifier and stabilizer. Carrageenan production and application of these rheological properties and their relationship with the larger, and thus accurate information on the rheological properties of carrageenan and its variation under various conditions on the production of great significance.
4.1 Carrageenan role in the production of jelly
Carrageenan as a good coagulant, can replace the usual agar, gelatin and pectin. Jelly made with agar lack of flexibility, higher prices; to do with the gelatin jelly drawback is the water freezing and melting point is low, preparation and storage of cold storage is required; with pectin disadvantage is the need to add sugar and adjust the high solubility proper pH can be solidified. Carrageenan not have these disadvantages, with the carrageenan jelly made from water and not flexible, so it became common jelly gel. Carrageenan in the application of jelly should note the following: First, as part of konjac gum carrageenan system, its relatively high solubility, and therefore warm. Such as the holding time is not enough, not completely dissolved, the bad taste to make the jelly, jelly can cause serious tender without forming; but holding time is too long, carrageenan and slightly alkaline, or sodium citrate and the like added the buffer, it is easy to acetylation degeneration occurs, resulting in "egg soup" phenomenon, may still not forming jelly. It is recommended not to heat after boiling in summer, warm in winter after boiling 10min, spring and autumn in between. Second, because carrageenan is not acid, acid temperature as low as possible, usually in the 70 ℃ -80 ℃ before or jelly filling according to the actual process conditions, the higher the temperature of carrageenan or more can easily be destroyed, affecting the taste, also proposed to add citric acid dissolved in water to avoid local over-acid; adjusting the pH value is generally not less than 4, a more sour taste should be supporting the use of other colloid; pasteurization will also affect the taste, according to the actual situation regulation. Third filter. In the boiling, use the mesh filter liquid, which aims to remove the insoluble particles of konjac gum, get a relatively transparent jelly, which could be the effect of some high-grade transparent jelly.
4.2 Carrageenan in candy Production
Fruit jelly with carrageenan make clear in our long production, the fruit flavor, moderate sweetness, refreshing non-stick teeth, and better transparency than agar, lower price than the agar, added to hard candy and candy in general make the product smooth in texture, more flexible, adhesive small, the stability increased. Carrageenan used in the candy should pay attention: First, carrageenan-based soft sugar high sugar concentrations in poorly soluble, it is proposed that the first of its dissolved in water, or prone to "trachoma", that is a one of the small particles. Second, reducing sugar content is too low, long storage time, is easy to return sand; reducing sugar content is too high, the boil when sugar is not easy to injection mold forming. Third, it could join the suit after the gelatin material, such as carrots, butter, powdered sugar, but to calculate the proportion of soft.
4.3 Carrageenan in ice cream Production
In the ice cream and ice cream production, carrageenan can fat distribution and other solid ingredients, prevent separation and milk composition in the manufacture and storage of ice time increases, it can make ice cream and ice cream Organization delicate, smooth and delicious. In ice cream production, carrageenan with milk because of the cation play a role, resulting in a unique gelling characteristics, increased formability and anti-ice melting, ice cream to improve the stability of the temperature fluctuations, is not easy when placed melt. In ice cream production, although not suitable for carrageenan-based stabilizers, but it is at very low concentrations can be as well to prevent whey separation of the secondary stabilizer. Because carrageenan Despite the increase in viscosity of the system, but not inclusive enough glue to stabilize the system. Locust bean gum, guar gum and carboxymethyl cellulose used alone or in combination is a better primary stabilizer, but they have the same shortcomings that lead to the mixture in ice cream whey separation. So join carrageenan can inhibit this phenomenon. Carrageenan used in ice cream should be noted: First, add a small amount of starch can be filled, there is more than the number of powder texture, poor taste; second, less the amount of carrageenan, used for the aging process after Freezing.