The performance of gellan gum solution

The performance of gellan gum solution

 

Temperature Hysteresis

Gellan gum has remarkable temperature hysteresis property, that is, the gelling temperature is far lower than the melting temperature of gel. In general, the former is between 20-50℃ while the latter is between 65-120℃ and both depend on the formation conditions of gel, including the type and concentration of positive ions. The temperature hysteresis of gellan gum is of great practical significance to the food industry. For example, some products require the process of gelling then melting while other products demand that the gel structure should remain stable during the heat treatment process.

 

Effects of Salts on Gellan Gum Gel

Pure gellan gum is a kind of compound salt and insoluble in cold water but with stirring, it will immediately disperse in the deionized water and increase the concentration of positive ions. For example, the water with medium hardness (equivalent to containing CaCO3, 180mg/kg) contributes to its dispersion in water. However, such ions as Ca2+, Mg2+, Na+ and K+ (in hard water, for example) can prevent the hydration of dispersed gellan gum with heat. Furthermore, the higher the concentration of positive ions is, the more unlikely it is to be hydrated even if heated to boiling.

 

Effects of Acid-Base on Gellan Gum Gel

The pH value of most products is between 4.0 and 8.0, and within this pH range, the gel strength of gellan gum will hardly change with the change of pH value. Thus, the application of gellan gum in food doesn’t need to take the effects of pH value into consideration. Some expert studies in America have reported that for the gellan gum gel formed by divalent cation; its gel strength will drop rapidly when the pH value is below 3.5 or above 8.5 while for that formed by monovalent cation, the gel strength shows slight fluctuation when the pH value is 3.5-1L.5. However, for the gel formed under the same condition of gel concentration, the gel strength for that of divalent cation is far higher than that of monovalent cation.

 

Effects of Enzymes on Gellan Gum Gel

Some American technologists once added various kinds of enzymes (including pectinase, α-amylase, β-amylase, cellulose, alginase, papain and lipase) to the gellan gum solution. The result shows that none of the enzymes have an effect on the solution viscosity and the gel strength. With this property, gellan gum can replace agar and act as the gelling agent microbiological culture media.

 

Compatibility with Other Kinds of Gum

In compounding, the hydrosols without gel property such as locust guar gum, guar gum, cellulose gum and xanthan gum have no obvious effects on the structure and properties of gellan gum gel. However, the hydrosols with gel property such as gelatin, the mixture of xanthan gum and locust bean gum, and starch enable the tissue structure to make significant changes.

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On June 27th, 2013, posted in: Products and Techniques by

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