Common Name:
~Gellan Gum,E418
SOURCE:
~A carbohydrate polymer produced by the bacterium Sphingomonas elodea formerly known as Pseudomonas elodea.
Qualities:
~ High Acyl or Low Acyl
~ Particle Size
~ Requires Heat for Activation
~ Low Usage Levels
~ Thermal Proces Tolerant
FUNCTIONALITY:
~ Thickener
~ Gel Formation
~ Suspension
Gellan Gum Plant Origin & Handling:
Gellan Gum is a type of hydrocolloid that is created using fermentation techniques. This carbohydrate polymer is produced by a bacterium called Sphingomonas elodea (previously known as Pseudomonas elodea). After the fermentation process, the medium is heated to eliminate any viable cells.
To obtain purified Gellan Gum, a precipitation step with alcohol is employed. Additionally, to produce Low Acyl (LA) forms of Gellan Gum, the level of acyl groups can be reduced through an alkali treatment before the alcohol precipitation step. This is in contrast to the native High Acyl (HA) form of Gellan Gum.
Gellan Gum Common Applications:
Originally, Gellan Gum was primarily developed as an alternative to Agar in microbiological culture media. However, it quickly demonstrated its advantages as a clear gelling agent in plant cell and tissue culture media, becoming widely used, comprising about 50% of the media compared to Agar.
Gellan Gum's first food application was in a beverage known as Orbitz™, where it served both gelling and suspension functionalities. Additionally, it found a place in high-sugar confectionery gel centers coated with hard or sugar shells, providing a vegan and vegetarian-friendly alternative to gelatin, making such items more desirable for these diets.
Despite being expensive per pound, the cost-effectiveness of Gellan Gum is reasonable due to its low usage levels, typically ranging from 0.01% to 0.03% by weight in beverages. In molecular gastronomy, the native type of Gellan Gum (High Acyl or HA) is used to create highly flavorful gels, adding culinary and textural interest. HA Gellan Gum forms soft, elastic, transparent gels that melt between 70-80°C, with its functionality influenced by cations and pH.
On the other hand, LA Gellan Gum forms firm, non-elastic, brittle gels in the presence of cations. It is recommended to hydrate Gellan Gum before introducing sugar into the formula. HA Gellan Gums offer excellent heat stability and low viscosity at high temperatures, making them ideal for use in HTST and UHT thermal processed products.
Moreover, HA Gellan Gum serves as a label-friendly alternative to carrageenan and microcrystalline cellulose (cellulose gum, cellulose gel) in shelf-stable fortified and meal replacement beverages, both dairy and non-dairy based.
GELLAN GUM Macromolecular Chemistry:
Gellan Gum's chemical structure consists of a linear polymer composed of a repeating tetra-saccharide unit. This unit includes glucose, glucuronic acid, and rhamnose. Along the polymer backbone, there are acyl group substitutions (glyceate and acetate) attached to the glucose residues. In commercial processing, these acyl substitutions can be removed or lost.
Due to the degree of acyl substitution, Gellan Gum is categorized into two groups: High Acyl (HA) and Low Acyl (LA). To facilitate dispersion, buffering salts and/or cations are often added. Complete hydration and activation of Gellan Gums require heat, and their functionality is highly influenced by soluble ions, temperature, and pH.
It's essential to note that processing recommendations can significantly vary between HA and LA Gellan Gums due to their distinct properties and characteristics.
