Physical and Chemical Properties of Carrageenan-e407

Physical and Chemical Properties of Carrageenan – e407

 

The food grade carrageenan appears as translucent plates or powders in white or fawn with shrinkage in the slightly glossy surface. Odorless or with little odor, and tasteless, it has a great smooth mouth feel and it can swell in cold water, while it can form a kind of free-flowing solution that are viscous transparent or slightly milky and it is insoluble in organic solvents. Furthermore, carrageenan can form various kinds of gels at low temperature in water or in cream-based food system.

 

Carrageenan has strong stability and its dry powder won’t get degraded for long time exposure. It is also very stable in neutral or alkaline solution, and won’t get hydrolyzed even with heat. In acid solution (especially pH≤4.0), however, can easily get acid hydrolysis and the gel strength and viscosity will decrease. It is worth mentioning that at neutral condition carrageenan will also get hydrolyzed, leading to the decrease in the gel strength, if it is heated for long at high temperature. All types of carrageenan can be soluble in hot water or hot milk, and can form a kind of free-flowing solution that are viscous transparent or slightly milky. In cold water, however, it can absorb water and swell but is insoluble.

 

1. Types of carrageenan

The κ-carrageenan is weak in hydrophilicity, so insoluble in water. However, the λ-carrageenan can be easily soluble in water under most conditions. The ι-carrageenan is probably somewhere in between. The κ-carrageenan is soluble in Na salts but insoluble in K, Ca salts, while the ι-carrageenan soluble in Na salts but can form thixotropy dispersions in Ca salts; and the λ-carrageenan is soluble in all salts.

Refined Carrageenan-kappa-κ-carrageenan

2. Other solutes

Inorganic salts play the main function in the hydration of carrageenan. Particularly, 1.5—2% KCl solution can prevent the solution of carrageenan at normal temperature while 4—4.6% NaCl solution or higher in solubility can do so. However, the solubility of sucrose has a little effect on the hydration of κ-carrageenan.

 

3. Temperature

The higher the temperature is, the better the solubility will be. The solubility is in proportion to the temperature.

 

4. PH value

In acid conditions, it can only swell (at normal temperature).

 

Classification and Related Properties of Carrageenan

 

Carrageenan can form semisolid transparent gel after being heated, melted and cooled. The kalium, ammonium and calcium cations can greatly enhance its coagulability. The κ-carrageenan is sensitive to kalium ion, so can form brittle gels and possess the bleeding property, while the ι-carrageenan is sensitive to calcium ion, so can form flexible gels but doesn’t possess the bleeding property, and the λ-carrageenan can’t form gels. In general, commercially available carrageenan mainly is the κ-carrageenan, if not strictly indicated, or a little unsegregated ι-carrageenan and λ-carrageenan. Some polysaccharides also have an effect on its coagulability. For example, locust bean gum helps to distinctly improve the gel strength and elasticity of the κ-carrageenan. The corn starch and wheat starch also helps to increase the gel strength. The gel formed by carrageenan has reversibility, that is, the gel will melt into solution with heat and return back when cooling off. Consequently, the change process is reversible but the general strength may be damaged.

 

 

According to the technological processes, carrageenan can be divided into Refined Carrageenan and Semi-refined Carrageenan.

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On February 5th, 2013, posted in: carrageenan, Products and Techniques by Tags:

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