What is High & Low Acyl Gellan Gum (E418) in food? Uses and Safety

Overview | Uses | Safety | Side effects | FAQs

Gellan gum, an ingredient made from fermentation by Sphingomonas elodea, is commonly used as a gelling agent, stabilizer and thickener in food and beverage. The European food additive number for it is E418. It is a soluble fiber with two types, high acyl and low acyl, and follows the different uses.

What is gellan gum?

Definition

By EFSA’s definition, gellan gum is a high-molecular-weight extracellular polysaccharide produced from the fermentation of a carbohydrate by strains of Pseudomonas elodea. (¹)

Structure

It is composed of tetrasaccharide repeat units, each containing two D-glucose units, one D-glucuronic acid and one L-rhamnose. (²)

What is it made of?

It is composed of polysaccharide, proteinaceous material (by nitrogen content, %N = 0-3.0%), and polyhydroxybutyrate (PHB) up to 25 wt%.

What is it made from?

Like Xanthan gum, gellan gum is also a bacterial polysaccharide which is produced by strains of Pseudomonas elodea. 

Now this strain is also named as Sphingomonas elodea or ATCC 31461. It is the only strain that can be used for production.

Manufacturing flow can be divided into two main processes, fermentation process and then through the purified process.

Fermentation

Culture the ATCC 31461 bacterial strain in the medium with a carbon source (common sugars), nitrogen sources and mineral salts.

Purification 

The purification process is different based on the various types of gellan gum.

• High acylated form: direct recovery from broth by alcohol precipitation. 
• Low acylated form: treat the broth with alkali and then with alcohol precipitation.
• Clarified form: filter low acylated gellan gum to remove cell residues and other insoluble components.

Two types of gellan gum 

Gellan gum is divided into two types, high acyl and low acyl form by the degree/percent of substitution by O-acyl groups. 

1. High acyl gellan gum

It is also called HA Gellan gum. Two acyl substituents acetate at C6 and glycerate at C2 on the first glucose unit of the repeating unit of tetrasaccharide, and on average, there is one glycerate per repeat and one acetate per every two repeats.

With the chemical structure follows: 

M+ = ½ Ca2+, K+, Na+, ½ Mg2+ From EFSA

2. Low acyl gellan gum

It is also called LA Gellan gum. It is partly deacylated or fully deacylated. Its common form is the fully deacylated one, with no detectable acyl groups, also called deacetylated gellan gum.

With the chemical structure follows:

The following are the Specification difference among the three types.

Specification

Appearance

An off-white powder. 

Solubility

It is the water-soluble anionic polysaccharide, fully soluble in water once heated, forming a viscous solution; insoluble in ethanol.

Low acyl VS high acyl gelation

The easiest way to form both gels is to cool hot solutions. 

The comparison as follows:

Low Acyl Gels:

1. It forms gels with cations, e.g. calcium(Ca2+), magnesium (Mg2+), sodium (Na+), and potassium (K+), as well as acid (H+) and the presence of these cations increases the gel strength and brittleness.
2. It forms gels itself at concentrations as low as 0.05%. (Handbook of hydrocolloids, Edited by G. O. Phillips and P. A. Williams, 2000)
3. Not thermally reversible

High Acyl Gels:

1. The gels and the properties are less dependent on the concentration of ions in solution. 
2. The needed concentration to form gel itself is around 0.2%. (Handbook of hydrocolloids, Edited by G. O. Phillips and P. A. Williams, 2000)
3. Thermally reversible.

Gel texture

The gels show very different textures (related with Acyl content), HA forms soft, elastic and non-brittle gels whereas LA forms firm, non-elastic and brittle gels. 

Their textures are at the two ends if compared with other common gelling agents: xanthan gum, LBG, gelatin, pectin, alginate, carrageenan, and agar.

Generally, the gel property as follows:

1. Heat stable: The gels are stable at high temperature as its solution is heated to 90–95°C for 10–15 min in the production process.
2. PH stable: stable in pH range between 3.5 and 8.
3. Synergistic with konjac glucomannan.

What are the application of gellan gum?

Gellan gum is a multi-functional hydrocolloid used as a gelling, texturizing, stabilizing, suspending, film-forming and structuring agent in food, beverage, personal care applications and pharmaceuticals.

Food

Commonly the usage level ranges from 0.1% to 1%. And usually, we can find it in plant-based drinks, fruit/flavoured still drinks, nectars, pastilles, gums, jellies & chews, meal replacements, desserts, and flavoured milk.

Dessert jellies

Water-based dessert jellies are commonly brittleness, cohesiveness, elastic, creamy, sticky, firm, wobbling, syneresis and easy demoulding. 

Gellan gum functions as a gelling, texturizing, stabilizing, suspending, film-forming and structuring agent in water desserts & dessert Gels.

LA or blends of HA and LA can be used to provide dessert jellies with a variety of textures.

How to make fruit juice jelly with LA gellan gum and gelatin?

1. Prepare ingredients: Water 500.0g (82.6%), Sugar 90.0g, (15.0%), Citric acid anhydrous 2.3g (0.38%), Tri sodium citrate dihydrate 1.6g, (0.26%), LA gellan gum, 0.35g (0.06%), Gelatin 10.2g (1.7%), Color and flavor as required.
2. Blend all the dry ingredients.
3. Heat the water to boil and dissolve the blended ingredients into the boiling water by stirring for 1-2 minutes.
4. Deposit and chill.

(Handbook of hydrocolloids, Edited by G. O. Phillips and P. A. Williams, 2000)

Beverage 

Gellan gum can be used as a suspension agent (for example, suspend jelly beads and form a smooth fluid gel), stabilizer and mouthfeel creator in juices, juice drinks, dairy alternative & plant-based beverages. (³)

Dairy

Drinking yogurts are more popular due to its health benefits. Gellan gum can control syneresis, provide suspension, create body & texture, and improve mouthfeel in yogurts.

Plant-based milk containing it to help plant protein suspended in the milk, such as almond milk and soy milk, some types are flavored.

Confectionery

Gellan gum can be applied in a range of confectionery products, which are rich in sugar, like gummy and chewy confections, marshmallows, jellies, pastes, candies and so on. 

Combinations of sugars (such as sucrose, glucose, fructose and corn syrups) with the hydrocolloid produces desirable jelly textures, gel clarity, flavour release and so on.

Bakery

High and low acyl gellan gum can be used in bakery mixes; bread, muffins and cakes; frozen dough icings, frostings and glazes. (⁴)

Cosmetics

Per “European Commission database for information on cosmetic substances and ingredients”, it can function as a film forming and viscosity controlling agents in cosmetic and personal care products. (⁵)

Others

Gellan Gum was initially an alternative for agar in solid culture media for the growth of various microorganisms (⁶). It is used for plant tissue and cell culture with the advantage of producing a high transparent gel than agar. (⁷)

Is gellan gum safe to eat?

Yes, it almost has no side effects and the safety has been approved by the U.S. Food and Drug Administration (FDA) and European Food Safety Authority (EFSA), as well as the Joint FAO/WHO Expert Committee on Food Additives (JECFA).

FDA 

The FDA claimed the food additive gellan gum may be safely used in food as a stabilizer and thickener. (⁸)

EFSA

Gellan Gum (E 418) is authorised as a food additive in the European Union (EU) in accordance with Annex II and Annex III to Regulation (EC) No 1333/2008 on food additives and categorized as “additives other than colours and sweeteners”  (⁹)

Re-evaluation the safety in 2018

After the study on genotoxicity, carcinogenicity, reproductive and developmental toxicity, EFSA concluded that “there is no need for a numerical acceptable daily intake (ADI) for gellan gum (E 418), and that there is no safety concern at the refined exposure assessment for the reported uses and use levels of gellan gum (E 418) as a food additive.” (¹⁰)

Uses

Its approved applications are listed separately with E418 in 4 food categories and in Group I in 67 food categories where the uses is quantum satis (QS).

Following foods may contain it:

• Jam, jellies and marmalades and sweetened chestnut purée
• Fruit or vegetable spreads
• Table-top sweeteners

Gellan gum (E 418) is also authorised used as a carrier in food enzymes and in all nutrients except nutrients intended to be used in foodstuffs for infants and young children in Annex III of Regulation (EC) No 1333/2008. (¹¹)

UK Food Standards Agency

Categorized as an emulsifier, stabiliser, thickener and gelling agent. (¹²)

Food Standards Australia New Zealand 

It is an approved ingredient in Australia and New Zealand with the code number 418. (¹³)

JECFA

Function Class: food additives, gelling agent, stabilizer, thickener. (¹⁴)

ADI: ADI not specified set since 1990.  (¹⁵)

What are the possible side effects? 

It is common that sometimes consumers have questions whether gellan gum is bad for our health and what are the side effects. It is generally safe and there were few health risks reported.

Allergy

EFSA did not find allergic reactions in humans after oral exposure to gellan gum.

Is it safe for pregnant?

There were no adverse effects from EFSA’s study of reproductive and developmental toxicity on rats up to 5% in the diet.

Frequently Asked Questions

Conclusion

Now you may have a good knowledge of the food additive – Gellan gum E418, from its production; two types: high acyl and low acyl and their comparison; properties, uses; approved safety, possible side effects and some FAQs such as is it vegan, gluten free, synthetic or natural.

EFSA indicated that gellan gum was found in 1,194 food products between January 2013 and January 2018, published on Mintel’s GNPD. What kinds of food packaging have you found this ingredient in? Let me know in the comments.