PRODUCTS

E 406

E 406=Agar= Agar Agar

CAS: 9002-18-0
European Community (EC) Number: 232-658-1
Molecular Formula: C14H24O9
IUPAC Name:
(2R,3S,4S,5R)-2-(hydroxymethyl)-6-[[(4R,5S)-4-hydroxy-3-methyl-2,6-dioxabicyclo[3.2.1]octan-8-yl]oxy]-4-methoxyoxane-3,5-diol

DESCRIPTION:

Agar agar, or simply called agar, is a hydrocolloid generally made from Gelidium and Gracilaria, commonly used as a gelling agent and thickener in food.
The European food additive number for it is E406.
E 406 is the first used phycocolloid with a history of 300 years, much earlier than alginates and carrageenan, which also are extracted from marine algae seaweed.

Agar agar is a tan powder.
E 406 is a natural product found in Gracilariopsis longissima, Gracilaria gracilis, and Pterocladiella capillacea with data available.
A complex sulfated polymer of galactose units, extracted from Gelidium cartilagineum, Gracilaria confervoides, and related red algae.
E 406 is used as a gel in the preparation of solid culture media for microorganisms, as a bulk laxative, in making emulsions, and as a supporting medium for immunodiffusion and immunoelectrophoresis.

Agar or agar-agar, is a jelly-like substance consisting of polysaccharides obtained from the cell walls of some species of red algae, primarily from ogonori (Gracilaria) and "tengusa" (Gelidiaceae).
E 406 is a structural carbohydrate existing in the cell walls of agarophyte algae.
E 406 is a mixture of two components, the linear polysaccharide agarose and a heterogeneous mixture of smaller molecules called agaropectin.
E 406 forms the supporting structure in the cell walls of certain species of algae and is released on boiling.

These algae are known as agarophytes, belonging to the Rhodophyta (red algae) phylum.
Agar has been used as an ingredient in desserts throughout Asia and also as a solid substrate to contain culture media for microbiological work.
E 406 can be used as a laxative; an appetite suppressant; a vegetarian substitute for gelatin; a thickener for soups; in fruit preserves, ice cream, and other desserts; as a clarifying agent in brewing; and for sizing paper and fabrics.
Agar-agar is a dried, hydrophilic, colloidal polysaccharide extracted from one of a number of related species of red algae (class Rhodophyceae)

E 406 is odourless or has a slight characteristic odour.
Unground agar usually occurs in bundles consisting of thin, membranous, agglutinated strips, or in cut, flaked or granulated forms.
E 406 may be light yellowish-orange, yellowish-grey to pale yellow, or colourless.

E 406 is tough when damp, brittle when dry.
Powdered agar is white to yellowish-white or pale yellow.
When examined in water under a microscope, agar powder appears more transparent.
In chloral hydrate solution, the powdered agar appears more transparent than in water, more or less granular, striated, angular and occasionally contains frustules of diatoms.
Gel strength may be standardised by the addition of dextrose and maltodextrines or sucrose

Agar-agar is a hydrocolloid extracted from red seaweeds that is widely used as a gelling agent in the food industry.
In its gelling power, agar is outstanding among the hydrocolloids.
Among its major properties one can mention its high gel strength at low concentrations, low viscosity in solution, high transparency in solution, thermo-reversible gel and sharp melting/setting temperatures.
E 406 may come in several forms: powdered, flakes, bars and threads.
Besides its use as a food additive, E 406 is also used on a lesser scale in other industrial applications.

Agar-agar is extracted from several types and species of red seaweeds belonging to the Rhodophyceae class.
These agar-containing seaweeds are called agarophytes and the major commercial species are Gracilaria and Gelidium.
The E 406 content of seaweeds varies according to the conditions of seawater.
Carbon dioxide concentration, oxygen tension, water temperature and intensity of solar radiation can have significant influence.

Seaweeds are usually harvested manually by fishermen in low depths at low tides or by diving using appropriate equipment.
After being harvested, seaweeds are placed under the sun to dry until they reach a humidity level that is ideal for processing.
Gelidium is obtained from natural seaweed beds mainly in Morocco, Spain, Portugal, Japan and South Korea, as attempts to cultivate it have not been successful.

On the other hand, Gracilaria seaweeds have been successfully cultivated on a commercial scale, particularly in China, Indonesia and Chile.
E 406 is a polysaccharide obtained by extracting red sea algae.
The genera of these seaweeds are mostly Gelidium and Gracilaria and are collected from different countries.
E 406 is not a single chemical substance, it is a polymer composed of Agarose and Agaropectin polysaccharides.

E 406 has thin layer is in powder form.
Features that differentiate the quality; factors such as gel strength, degree of gelling and melting, color, solubility change the quality of agar.

Generally, the gelling temperature of the agar is cooled to a hot solution of 30-40 ° C to obtain gelling.
E 406 melts when heated above 90 - 95 ° C.
E 406 has the ability to draw up to twenty times the weight of the agar.

E 406 is preferred for special uses that the heat-resistant gel formation and the gel-forming temperature and melting temperature differ.
For this purpose, Agar is used as a stabilizer in cookies, puddings, decoration jellies, pastry fillings, cream pastries and other similar foods.

E 406 is used in cake decorations (sugar coatings and creams) to increase stability.
And E 406 prevents the sugared liquid from flowing and sticking to the package.
Agar Agar is used as a medium in laboratories.

EU Food Additive Definition:
Agar is a hydrophilic colloidal polysaccharide consisting mainly of galactose units with a regular alternation of L and D isomeric forms.
These hexoses are alternately linked with alpha-1,3 and beta-1,4 bonds in the copolymer.
On about every tenth D-galactopyranose unit one of the hydroxyl groups is esterified with sulphuric acid which is neutralised by calcium, magnesium, potassium or sodium.
E 406 is extracted from certain strains of marine algae of the families Gelidiaceae and Gracilariaceae and relevant red algae of the class Rhodophyceae.
The main purpose of using agar in food with its following three advantages:
•   A natural ingredient, suitable for vegetarians to replace gelatine derived from animal skin and bones.
•   The high gelling hysteresis between the gelling and melting temperatures.
•   Gel reversibility
Production Process of Agar:
Powdered agar-agar is a product mostly used for industrial applications.
Flakes, bars and threads are mostly used in cooking.
The manufacture of powdered and flake-like agar-agar is accomplished by the Gel Press method by pressing the agar gel.
Agar-agar in bar and strip forms is manufactured through a more traditional production method by freezing and thawing the agar gel.

Etymology of Agar:
The word "agar" comes from agar-agar, the Malay name for red algae (Gigartina, Gracilaria) from which the jelly is produced.
Agar is also known as Kanten (Japanese: 寒天) (from the phrase kan-zarashi tokoroten (寒曬心太) or “cold-exposed agar”), Japanese isinglass, China grass, Ceylon moss or Jaffna moss.
Gracilaria lichenoides is specifically referred to as agal-agal or Ceylon agar.

History of Agar:
Agar may have been discovered in Japan in 1658 by Mino Tarōzaemon (美濃太郎左衞門), an innkeeper in current Fushimi-ku, Kyoto who, according to legend, was said to have discarded surplus seaweed soup (Tokoroten) and noticed that it gelled later after a winter night's freezing.
Over the following centuries, agar became a common gelling agent in several Southeast Asian cuisines.

Agar was first subjected to chemical analysis in 1859 by the French chemist Anselme Payen, who had obtained agar from the marine algae Gelidium corneum.

Beginning in the late 19th century, agar began to be used as a solid medium for growing various microbes.
Agar was first described for use in microbiology in 1882 by the German microbiologist Walther Hesse, an assistant working in Robert Koch's laboratory, on the suggestion of his wife Fanny Hesse.
Agar quickly supplanted gelatin as the base of microbiological media, due to its higher melting temperature, allowing microbes to be grown at higher temperatures without the media liquefying.
With its newfound use in microbiology, agar production quickly increased.

This production centered on Japan, which produced most of the world's agar until World War II.
However, with the outbreak of World War II, many nations were forced to establish domestic agar industries in order to continue microbiological research.
Around the time of World War II, approximately 2,500 tons of agar were produced annually.
By the mid-1970s, production worldwide had increased dramatically to approximately 10,000 tons each year.
Since then, production of agar has fluctuated due to unstable and sometimes over-utilized seaweed populations.

Composition of E 406:
E 406 consists of a mixture of two polysaccharides: agarose and agaropectin, with agarose making up about 70% of the mixture.
Agarose is a linear polymer, made up of repeating units of agarobiose, a disaccharide made up of D-galactose and 3,6-anhydro-L-galactopyranose.
Agaropectin is a heterogeneous mixture of smaller molecules that occur in lesser amounts, and is made up of alternating units of D-galactose and L-galactose heavily modified with acidic side-groups, such as sulfate and pyruvate.

Agar exhibits hysteresis, solidifying at about 32–40 °C (305–313 K, 90–104 °F) but melting at 85 °C (358 K, 185 °F).
This property lends a suitable balance between easy melting and good gel stability at relatively high temperatures.
Since many scientific applications require incubation at temperatures close to human body temperature (37 °C), agar is more appropriate than other solidifying agents that melt at this temperature, such as gelatin.

Uses of Agar:
Culinary:
Agar-agar is a natural vegetable gelatin counterpart.
E 406 is white and semi-translucent when sold in packages as washed and dried strips or in powdered form.
E 406 can be used to make jellies, puddings, and custards.
When making jelly, E 406 is boiled in water until the solids dissolve.

Sweetener, flavoring, coloring, fruits and or vegetables are then added, and the liquid is poured into molds to be served as desserts and vegetable aspics or incorporated with other desserts such as a layer of jelly in a cake.
Agar-agar is approximately 80% dietary fiber, so E 406 can serve as an intestinal regulator.
Its bulking quality has been behind fad diets in Asia, for example the kanten (the Japanese word for agar-agar) diet.

Once ingested, kanten triples in size and absorbs water.
This results in the consumers feeling fuller.
This diet has recently received some press coverage in the United States as well.
The diet has shown promise in obesity studies.

Asian culinary:
One use of agar in Japanese cuisine (Wagashi) is anmitsu, a dessert made of small cubes of agar jelly and served in a bowl with various fruits or other ingredients.
E 406 is also the main ingredient in mizu yōkan, another popular Japanese food.

In Philippine cuisine, Agar is used to make the jelly bars in the various gulaman refreshments like Sago't Gulaman, Samalamig, or desserts such as buko pandan, agar flan, halo-halo, fruit cocktail jelly, and the black and red gulaman used in various fruit salads.
In Vietnamese cuisine, jellies made of flavored layers of agar agar, called thạch, are a popular dessert, and are often made in ornate molds for special occasions.
In Indian cuisine, agar agar is used for making desserts.
In Burmese cuisine, a sweet jelly known as kyauk kyaw is made from agar.
Agar jelly is widely used in Taiwanese bubble tea.

Other culinary:
E 406 can be used as addition to or as a replacement for pectin in jams and marmalades, as a substitute to gelatin for its superior gelling properties, and as a strengthening ingredient in souffles and custards.
Another use of agar-agar is in a Russian dish ptich'ye moloko (bird's milk), a rich jellified custard (or soft meringue) used as a cake filling or chocolate-glazed as individual sweets.

Agar-agar may also be used as the gelling agent in gel clarification, a culinary technique used to clarify stocks, sauces, and other liquids.
Mexico has traditional candies made out of Agar gelatin, most of them in colorful, half-circle shapes that resemble a melon or watermelon fruit slice, and commonly covered with sugar.
They are known in Spanish as Dulce de Agar (Agar sweets)

Agar-agar is an allowed nonorganic/nonsynthetic additive used as a thickener, gelling agent, texturizer, moisturizer, emulsifier, flavor enhancer, and absorbent in certified organic foods.

Microbiology:
An agar plate or Petri dish is used to provide a growth medium using a mix of agar and other nutrients in which microorganisms, including bacteria and fungi, can be cultured and observed under the microscope.
E 406 is indigestible for many organisms so that microbial growth does not affect the gel used and it remains stable.

Agar is typically sold commercially as a powder that can be mixed with water and prepared similarly to gelatin before use as a growth medium.
Other ingredients are added to the agar to meet the nutritional needs of the microbes.
Many microbe-specific formulations are available because some microbes prefer certain environmental conditions over others.
E 406 is often dispensed using a sterile media dispenser.

Motility assays:
As a gel, an agar or agarose medium is porous and therefore can be used to measure microorganism motility and mobility.
The gel's porosity is directly related to the concentration of agarose in the medium, so various levels of effective viscosity (from the cell's "point of view") can be selected, depending on the experimental objectives.

A common identification assay involves culturing a sample of the organism deep within a block of nutrient agar.
Cells will attempt to grow within the gel structure.
Motile species will be able to migrate, albeit slowly, throughout the gel, and infiltration rates can then be visualized, whereas non-motile species will show growth only along the now-empty path introduced by the invasive initial sample deposition.

Another setup commonly used for measuring chemotaxis and chemokinesis utilizes the under-agarose cell migration assay, whereby a layer of agarose gel is placed between a cell population and a chemoattractant.
As a concentration gradient develops from the diffusion of the chemoattractant into the gel, various cell populations requiring different stimulation levels to migrate can then be visualized over time using microphotography as they tunnel upward through the gel against gravity along the gradient.

Plant biology:
Research grade agar is used extensively in plant biology as it is optionally supplemented with a nutrient and/or vitamin mixture that allows for seedling germination in Petri dishes under sterile conditions (given that the seeds are sterilized as well).
Nutrient and/or vitamin supplementation for Arabidopsis thaliana is standard across most experimental conditions.
Murashige & Skoog (MS) nutrient mix and Gamborg's B5 vitamin mix in general are used.
A 1.0% agar/0.44% MS+vitamin dH2O solution is suitable for growth media between normal growth temps.

When using agar, within any growth medium, it is important to know that the solidification of the agar is pH-dependent.
The optimal range for solidification is between 5.4 and 5.7.

Usually, the application of potassium hydroxide is needed to increase the pH to this range.
A general guideline is about 600 µl 0.1M KOH per 250 ml GM.
This entire mixture can be sterilized using the liquid cycle of an autoclave.

This medium nicely lends itself to the application of specific concentrations of phytohormones etc. to induce specific growth patterns in that one can easily prepare a solution containing the desired amount of hormone, add it to the known volume of GM, and autoclave to both sterilize and evaporate off any solvent that may have been used to dissolve the often-polar hormones.
This hormone/GM solution can be spread across the surface of Petri dishes sown with germinated and/or etiolated seedlings.

Experiments with the moss Physcomitrella patens, however, have shown that choice of the gelling agent – agar or Gelrite – does influence phytohormone sensitivity of the plant cell culture.

Pharmacology and Biochemistry:
Culture Media:
Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells.
The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media.
Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.

Cooking:
E 406 is used as a thickening agent for soups, fruits preserves, ice cream, sauces, jelly-based desserts, custards, puddings and other tasty treats.
E 406 easily gels most liquids and the gels can range from soft to hard, depending on the amount used.
E 406 can also be used to make dense foams when used in an ISI foamer.

Functionality and applications of Agar:
Food Industry:
An agar-agar solution in hot water forms a characteristic gel after setting, with a melting point between 85º to 95º C, and a gelling point between 32º a 45º C.
This physical property makes the gel very useful as an additive when used in many applications in the food industry.

Milk Products:
E 406 for Milk Products:
Ice Creams, Yogurts, Milk desserts, Puddings, Processed cheeses

Sweets and Confectionary:
E 406 for Sweets and Confectionary:
Candy bars, Jelly candies, Marshmallows, Jams and Jellies, Marmalades, Fruit Jelly Dessert, Meringues

Beverages:
E 406 for Drinks:
Clarifying and refining of juices, beers and wines

Bakery:
E 406 for Bakery:
Sugar Icings, Pie fillings, Bread dough, Chiffon pies, Cake glaze

Other industrial applications:
Agar-agar gel has the interesting property of inhibiting the characteristic liquefying that occurs in the enzyme action of microorganisms.
This property finds a wide variety of applications in the medical and pharmaceutical industries.
Agar-agar is used as a substratum in preparing bacteria cultures in microbiology, as laxatives and therapeutic agents in the treatment of malfunctions of the digestive tract, as a retarding agent and carrier in the management of medicines, antibiotics, vitamins, as a barium sulfate suspension agent in radiology, as a stabilizer in cholesterol solutions, and as a suspension agent in several types of emulsions.
Agar-agar has other industrial applications as well where a gelling agent is needed, such as in dental prosthetics, photographic emulsions, differentiation of proteins through electrophoresis, chromatography through exclusion of sizes, molding of materials and as plant culture tissues in biotechnology.

Medical and Pharmaceutical Industry:
Microbiology, Laxative, Therapeutic agent, Suspension agent of emulsion, Stabilizing agent of solution

Other Applications of E 406 :
Dental prosthetics, Electrophoresis, Chromatography, Impression materials, Plant Biotechnology

Gelling Properties of E 406:
The gelling portion of agar-agar has a double helical structure.
Double helices aggregate to form a three-dimensional structure framework which holds the water molecules within the interstices of the framework.
Thus, thermo-reversible gels are formed.
The gelling property of agar-agar is due to the three equatorial hydrogen atoms on the 3,6-anhydro-L-galactose residues, which constrain the molecule to form a helix.

The interaction of the helixes causes the formation of the gel.
Regarding its gelling power, agar-agar is outstanding among other hydrocolloids.
Agar-agar gels can be formed in very dilute solutions, containing a fraction of 0.5% to 1.0% of agar-agar.

These gels are rigid, brittle, have well defined shapes, as well as sharp melting and gelling points.
Moreover, they clearly demonstrate the interesting phenomenon of syneresis (spontaneous extrusion of water through the surface of the gel), and hysteresis (temperature interval between melting and gelling temperatures).
Gelling occurs at temperatures far below the gel melting temperature.

A 1.5% solution of agar-agar forms a gel on cooling to about 32º to 45º C that does not melt below 85º C.
This hysteresis interval is a novel property of agar-agar that finds many uses in food applications.
The gel strength of the agar-agar is influenced by concentration, time, pH, and sugar content.
The pH noticeably affects the strength of the agar gel; as the pH decreases, the gel strength weakens. Sugar content has also a considerable effect over agar gel.
Increasing levels of sugar make gels with harder but less cohesive texture.

Solubility Properties of E 406:
Agar-agar is insoluble in cold water, but it swells considerably, absorbing as much as twenty times its own weight of water.
Agar dissolves readily in boiling water and sets to a firm gel at concentrations as low as 0.50%. Powdered dry agar-agar is soluble in water and other solvents at temperatures between 95º to 100ºC.

Moistened agar flocculated by ethanol, 2-propanol or acetone, or salted out by high concentrations of electrolytes, is soluble in a variety of solvents at room temperature.
Special types of agar-agar that passes through additional processes are soluble at lower temperatures between 85º to 90º C.
They are marketed as Quick Soluble Agar or Instant Agar.

Viscosity Properties of E 406:
The viscosity of agar solutions varies widely and is markedly dependent upon the raw material source.
The viscosity of an agar solution at temperatures above its gelling point is relatively constant at pHs 4.5 to 9.0, and is not greatly affected by age or ionic strength within the pH range 6.0 to 8.0. However, once gelling starts viscosity at constant temperature increases with time.

Stability Properties of E 406:
An agar-agar solution is slightly negatively charged.
Its stability depends upon two factors: hydration and the electric charge.

The removal of both factors result in flocculation of the agar-agar.
Prolonged exposure to high temperatures can degrade solutions of agar-agar, resulting in a lower gel strength after temperature decrease and gel formation.
The effect is accelerated by decreasing pH .
Therefore, it should be avoided to expose agar-agar solutions to high temperatures and to pHs lower than 6.0 for prolonged periods of time.

Agar-agar in the dry state is not subject to contamination by microorganisms.
However, agar-agar solutions and gels are fertile media for bacteria and/or molds and appropriate precautions should be taken to avoid the growth of microorganisms.
Setting and melting point of E 406:
1% agar solution solidifies at 32 ~ 42 °C, its gel has elasticity, and its melting point is 80 ~ 96 °C.
Many of its uses take advantage of this large difference between gelling and melting temperature.

When compared with gelatin gels, it is tasteless, odorless, and sets more firmly, even at room temperature.
Gelatin gels melt around 35-40 °C.

Reversibility of E 406:

Agarose produces ‘physical gels’ which means the gel formed only by hydrogen bonds which make the gel reversible.
That’s to say, E 406 melts just by heating but gels again upon cooling.

These transformations can be repeated.
The reversibility is an important property of agar gel.
Gelatin also has the same characteristics.
This advantage can be used in a lot of applications, such as in food, microbiology, biochemistry and so on.

On the contrary, the ‘chemical gels’ is taken place by covalent bonds which can be considered through a chemical reaction and shape the gel irreversible.

Synergies of E 406:

Agar obtained from Gelidium is synergistic with locust bean gum (LBG) due to the agaropectin in Gelidium.
The increased gel strength, decreased rigidity and enhanced elasticity are observed in the gel formed by the mixture of LBG and Gelidium agar.

Agar comes from Gracilaria shows synergy with sugar, resulting in an increased gel strength when used in high sugar concentration (around 60%) products, such as jams and jellies

Agar Hydration:
In order for agar to work successfully it first needs to hydrate, or absorb water.
To properly hydrate agar it must be brought to a boil at 212°F (100°C) and simmered for 3 to 5 minutes.
Agar does not hydrate well in acidic liquids, making gelling difficult.

To get around this issue, first hydrate the agar in a neutral liquid and then add it to the acidic liquid. Agar Will form gels at 88 F and does not melt below 136 F.
Agar is a gel at room temperature, remaining firm at temperature as high as 65°C.
Agar melts at approximately 85°C, a different temperature from that at which it solidifies, 32-40°C.
This property is known as hysteresis.
Agar exhibits hysteresis, melting at 85 °C (358 K, 185 °F) and solidifying from 32–40 °C (305–313 K, 90–104 °F).
This property lends a suitable balance between easy melting and good gel stability at relatively high temperatures.

Other uses:
E 406 is used:
•   As an impression material in dentistry.
•   As a medium to precisely orient the tissue specimen and secure it by agar pre-embedding (especially useful for small endoscopy biopsy specimens) for histopathology processing.
•   To make salt bridges and gel plugs for use in electrochemistry.
•   In formicariums as a transparent substitute for sand and a source of nutrition.
•   As a natural ingredient in forming modeling clay for young children to play with.
•   As an allowed biofertilizer component in organic farming.
•   As a substrate for precipitin reactions in immunology.
•   At different times as a substitute for gelatin in photographic emulsions, arrowroot in preparing silver paper and as a substitute for fish glue in resist etching.
•   As an MRI elastic gel phantom to mimic tissue mechanical properties in Magnetic Resonance Elastography.
•   Ingredient Of Culture Media In Microbiology
•   Antitackiness & Antistalling Agent In Baked Goods
•   Ingredient In Desserts & Beverages, Laxatives & Health Foods, Pet Foods, Impression Materials
•   Ingredient In Pharmaceutical Preparations, Waveset Preparations
•   Laboratory Agent In Chem & Biological Applications
•   In production of medicinal encapsulations and ointments; as dental impression mold base; as corrosion inhibitor
•   Sizing for silks and paper; dyeing and printing fabric and textiles; in adhesives; vet: laxative for dogs and cats, demulcent
•   Medication
Gelidium agar is used primarily for bacteriological plates. Gracilaria agar is used mainly in food applications.

In 2016, AMAM, a Japanese company, developed a prototype for Agar-based commercial packaging system called Agar Plasticity, intended as a replacement for oil-based plastic packaging.

Methods of Manufacturing:
The agar can be extracted from the seaweed with hot water, followed by freezing and thawing for purification.
Commercial extraction procedures involve washing, chemical extraction, filtration, gelation, freezing, bleaching, washing, drying, and milling.

Absorption, Distribution and Excretion of Agar:
Agar passes through the intestinal tract mostly unabsorbed.

Mechanism of Action:
Agar dissolves or swells in water to form an emollient gel or viscous soln that serves to maintain the feces soft & hydrated.
The resulting bulk promotes peristalsis, & transit time is reduced.

Molecular Structure of Agar Agar:
Agarose, the gelling fraction, is a neutral linear molecule essentially free of sulfates, consisting of chains of repeating alternate units of ß-1,3-linked- D-galactose and a-1,4-linked 3,6-anhydro-L-galactose.

Agaropectin, the non gelling fraction, is a sulfated polysaccharide (3% to 10% sulfate), composed of agarose and varying percentages of ester sulfate, D-glucuronic acid, and small amounts of pyruvic acid.
The proportion of these two polymers varies according to the species of seaweed.
Agarose normally represents at least two-thirds of the natural agar-agar.

Four types of E 406:
According to the different appearance and application, food grade agar in the market can be classified into 4 types.
Respectively bar, strip (string), flake and powder.

Agar powder is mostly used for industrial applications.
Flakes, bars and strips are mostly used in cooking.

Strips and Bars :
Strips and bars are the old forms which are manufactured through a more traditional production method by freezing and thawing the agar gel.
Sometimes they are called natural agar.

The gels are cut into square bars or extruded to produce spaghetti-like strips 25–40 cm long after cooling down.
These two types are produced mostly from Gelidium and commonly used at home to prepare traditional dishes.
Before cooking, these two forms need to soak before soften, and then put in boiled water to make it completely dissolved.
Later add other ingredients, such as sweeteners, colors, flavours, or fruits to make the recipes.

Flakes and Powder:
Flakes and powder are smaller size ones that can quickly dissolve in boiling water.
Soaking may be needed for flakes before cooking.

Chemical and Physical Properties of E 406:
Molecular Weight:   336.33   g/mol
XLogP3-AA:   -2.2
Hydrogen Bond Donor Count:   4
Hydrogen Bond Acceptor Count:   9
Rotatable Bond Count:   4
Exact Mass:   336.14203234   g/mol
Monoisotopic Mass:   336.14203234   g/mol
Topological Polar Surface Area:   127 Å²
Heavy Atom Count:   23
Formal Charge:   0
Complexity:   408
Isotope Atom Count:   0
Defined Atom Stereocenter Count:   6
Undefined Atom Stereocenter Count:   4
Defined Bond Stereocenter Count:   0
Undefined Bond Stereocenter Count:   0
Covalently-Bonded Unit Count:   1
Compound Is Canonicalized:   Yes
Color/Form:
Transparent strips or coarse or fine powder
Thin, translucent, membranous pieces, or pale buff powder
Odor: Odorless
Taste: Tasteless
Solubility:
•   less than 1 mg/mL at 63° F (NTP, 1992)
•   Insoluble in cold water; soluble in boiling water
•   Slowly sol in hot water to a viscid soln
•   Insol in cold water
•   Insol in alcohol
Decomposition:
When heated to decomposition, Agar emits acrid smoke and fumes.
Viscosity:
Relatively low viscosities for seaweed extracts; viscosity is dependent on temp & ph, but fairly constant from ph 4.5-9.0
Appearance:   Yellowish powder
Particle size:   Mesh 80
Moisture content:   Max. 18 %
Water absorption:   Max. 75 c.c.
Acid insoluble ash:   Max. 0,5 %
Total ash:   Max. 6,5 %
Foreign insoluble material:   Max 1,0 %
PH:   6.5 to 7.5
Gel Strength (sol 1.5 % at 20ºC):   700 to 1.100 g/cm2
Viscosity (sol 1.5% at 60ºC):   10 to 100 cps
Melting Point:   85 to 95 ºC
Setting Point:   32 to 45 ºC
Solubility:   Boiling water
Arsenic:   Max. 3 ppm
Lead:   Max. 5 ppm

Microbial Properties:
Total Plate Count:   < 5000 CFU / g
Mold and Yeast:   < 500 CFU / g
E.Coli:   Negative
Salmonella:   Negative
CAS: 9002-18-0
European Community (EC) Number: 232-658-1
Molecular Formula: C14H24O9
IUPAC Name:
(2R,3S,4S,5R)-2-(hydroxymethyl)-6-[[(4R,5S)-4-hydroxy-3-methyl-2,6-dioxabicyclo[3.2.1]octan-8-yl]oxy]-4-methoxyoxane-3,5-diol

SAFETY INFORMATION ABOUT E 406:

Hazards Identification:
Fire Hazards:
Flash point data for this chemical are not available.
Agar is probably combustible.

First Aid Measures:
EYES:
First check the victim for contact lenses and remove if present.
Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center.
Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician.
IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.
SKIN:
IMMEDIATELY flood affected skin with water while removing and isolating all contaminated clothing. Gently wash all affected skin areas thoroughly with soap and water.
If symptoms such as redness or irritation develop, IMMEDIATELY call a physician and be prepared to transport the victim to a hospital for treatment.
INHALATION:
IMMEDIATELY leave the contaminated area; take deep breaths of fresh air.
If symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop, call a physician and be prepared to transport the victim to a hospital.
Provide proper respiratory protection to rescuers entering an unknown atmosphere.
Whenever possible, Self-Contained Breathing Apparatus (SCBA) should be used; if not available, use a level of protection greater than or equal to that advised under Protective Clothing.
INGESTION:
DO NOT INDUCE VOMITING.
If the victim is conscious and not convulsing, give 1 or 2 glasses of water to dilute the chemical and IMMEDIATELY call a hospital or poison control center.
Be prepared to transport the victim to a hospital if advised by a physician.
If the victim is convulsing or unconscious, do not give anything by mouth, ensure that the victim's airway is open and lay the victim on his/her side with the head lower than the body.
DO NOT INDUCE VOMITING. IMMEDIATELY transport the victim to a hospital.

Fire Fighting:
Fires involving this material can be controlled with a dry chemical, carbon dioxide or Halon extinguisher.
Accidental Release Measures:
Disposal Methods:
SRP:
At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision.
Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.
Handling and Storage:
Nonfire Spill Response:
SMALL SPILLS AND LEAKAGE:
If you spill this chemical, FIRST REMOVE ALL SOURCES OF IGNITION, then dampen the solid spill material with toluene, then transfer the dampened material to a suitable container.
Use absorbent paper dampened with toluene to pick up any remaining material.
Your contaminated clothing and absorbent paper should be sealed in a vapor-tight plastic bag for eventual disposal.
Solvent-wash all contaminated surfaces with toluene followed by washing with a soap and water solution.
Do not reenter the contaminated area until the Safety Officer (or other responsible person) has verified that the area has been properly cleaned.
STORAGE PRECAUTIONS: You should store this material in a refrigerator.

Exposure Control and Personal Protection:
Personal Protective Equipment (PPE):
RECOMMENDED RESPIRATOR:
Where the neat test chemical is weighed and diluted, wear a NIOSH-approved half face respirator equipped with an organic vapor/acid gas cartridge (specific for organic vapors, HCl, acid gas and SO2) with a dust/mist filter.

Stability and Reactivity:
Air and Water Reactions:
Water insoluble.
Reactive Group:
Alcohols and Polyols
Ethers
Reactivity Profile:
Flammable and/or toxic gases are generated by the combination of alcohols with alkali metals, nitrides, and strong reducing agents.
They react with oxoacids and carboxylic acids to form esters plus water.
Oxidizing agents convert them to aldehydes or ketones.
They exhibit both weak acid and weak base behavior.

Regulatory Information:
FDA Requirements:
Substance added directly to human food affirmed as generally recognized as safe (GRAS).
Agar-agar used as a stabilizer in animal drugs, feeds, and related products is generally recognized as safe when used in accordance with good manufacturing or feeding practice.
Manufacturers, packers, and distributors of drug and drug products for human use are responsible for complying with the labeling, certification, and usage requirements as prescribed by the Federal Food, Drug, and Cosmetic Act, as amended
Agar or agar-agar was discovered in the late 1650s or early 1660s by Mino Tarozaemon in Japan, where it is called kanten.
Agar is derived from the polysaccharide agarose, which forms the supporting structure in the cell walls of certain species of algae, and which is released on boiling.
Agarose is a polysaccharide polymer material, generally extracted from seaweed.
Agarose is a linear polymer made up of the repeating unit of agarobiose, which is a disaccharide made up of D-galactose and 3,6-anhydro-L-galactopyranose.
Agarose is one of the two principal components of agar, and is purified from agar by removing agar's other component, agaropectin.

Other names for E 406:
Agar thickening agent, agar agar seaweed, agar agar thickener, agar food additive

QUESTIONS AND ANSWERS ABOUT E 406:

What is E 406 made from?
From the above FDA’s definition, we can know it is obtained from the red algae of the class Rhodophyceae.
In general, these algae belong to Gelidium and Gracilaria, both are the principal seaweeds for commercially producing agar.
These agar seaweeds are also called agarophytes.

1. Gelidium
Agar Agar grows best at 15-20°C, difficult to cultivate and most harvested naturally in Spain, Portugal, Morocco, Japan and Mexico.
Strong-gelling agar can be extracted directly from it.

Agar Agar is the preferred seaweed source for making bacteriological and pharmaceutical grade agar and agarose.

2. Gracilariaceae
A good plant source for producing food grade agar.
Temperatures of 20°C or higher are requested for at least three months of the year for its growth.

Agar Agar is cultivated on a commercial scale, such as in Chile, Argentina, Brazil, Indonesia, China, the Philippines, and Vietnam.

Once these species were considered low quality due to the strength of a gel it forms. But later, manufacturers finding this property can be improved with alkali treatment to remove the sulfates.

What is E 406 made of?
Agar Agar is a polysaccharide, consisting primarily of D- and L-galactose units.
About every tenth D-galactopyranose unit contains a sulfate ester group.
Calcium, magnesium, potassium or sodium cations are also associated with the polysaccharide.

Agar Agar is a complex mixture of polysaccharides, not only consists of two major polysaccharides, agarose and agaropectin, but also with other varieties, some are rich in sulfate, others in pyruvate.

Its composition depends on the sources of seaweed and the production process employed.

1. Agarose
The major component of agar, around 70% or more of its total weight.
Agarose provides the gelling power and is free of sulfates.
Agarose is made up of the repeating unit of agarobiose, which is a disaccharide, composed of D-galactose and 3–6,anhydro- L-galactose, contributing to the main structure of agar.

2. Agaropectin
The non-gelling fraction, a charged sulfated polysaccharide that will influence solution properties, gel strength and gel features.

How is E 406 made?
In general, the manufacturing process of agar powder has the following steps:

Algae harvesting: agar plants mature in summer.
Preliminary drying: the moisture content can be reduced around 80% by natural or artiﬁcial dehydration.
Bleaching: sodium hypochlorite and/or H2O2 are used.
Extraction: after this process, agar is dissolved in boiling water.
This process may be different depending on the type of agarophyte and the product quality needed. Gelidium is processed under pressure (105–110°C for 2–4 h) and Gracilaria is usually treated with water at 95–100°C for 2–4 h.
Before the extraction, alkaline treatment (with sodium hydroxide) is usually employed for Gracilaria to hydrolyze the sulfates and so the agar gel-forming ability increased.
Otherwise, the gel strength is too low for commercial use.
Rest steps: ﬁltration, gelling and freezing/thawing, drying, milling and packing.

Is E 406 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
It is GENERALLY RECOGNIZED AS SAFE (GRAS) and can be used as an emulsifier or emulsifier salt, flavor enhancer, processing aid, stabilizer or thickener, surface-finishing agent and texturizer in food.

The following food may have it and with the approved maximum use levels :
Baked goods and baking mixes: 0.8%
Confections and frostings: 2.0%
Soft candy: 1.2%
All other food categories: 0.25%
EFSA
Agar Agar (E 406) 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”

Safety re-evaluation in 2016:
After the study of genotoxicity, carcinogenicity, reproductive, developmental toxicity and so on, EFSA concluded that “no need for a numerical ADI for agar, and that there is no safety concern for the general population at the reﬁned exposure assessment for the reported uses of agar as food additive.”

Is E 406 gluten free?
Yes, Agar agar is gluten free.

Synonyms:
MeSH Entry Terms:
Agar
Depositor-Supplied Synonyms:
Agar

9002-18-0

(2R,3S,4S,5R)-2-(hydroxymethyl)-6-[[(4R,5S)-4-hydroxy-3-methyl-2,6-dioxabicyclo[3.2.1]octan-8-yl]oxy]-4-methoxyoxane-3,5-diol

MFCD00081288

Agar (bacteriological)

Agar, plant cell culture tested

Agar, pure, powder Bacteriology and molecular biology grade