AGAR

Agar is a natural polysaccharide hydrocolloid, widely used as a gelling, thickening, and stabilizing agent in food, microbiology, and pharmaceutical applications.
Agar is obtained from red seaweeds (Rhodophyceae), mainly species of Gelidium and Gracilaria.
Agar belongs to the class of marine-derived gums.

CAS Number: 9002-18-0
Molecular Formula: C14H24O9
Molecular Weight: 336.33496
EINECS Number: 232-658-1

Synonyms: Agar, 9002-18-0, Gelose, Ceylon, Chinese gelatin, Japan isinglass, Bengal gelatin, Layor carang, Bengal isinglass, Ceylon isinglass, Japan agar, Japanese gelatin, Macassar gelatin, Agar agar flake, Chinese isinglass, Isinglass, japanese, Agar (Gelidium spp.), Digenea simplex mucilage, Kantenmatsu, Agargel, Phytagar, macassar gum, Agaropectin (mixture with agarose), Agarose (mixture with agaropectin), FEMA No. 2012, Difco bacto agar, Seaweed agar raw, Seaweed agar dried, GAM medium, Agar unspecified, Oxoid III, Oxoid L 11, RefChem:915247, S 100 (polysaccharide), 3PBT7NM2M0, LPT5H1B7X5, 89T13OHQ2B, CHEBI:2509, INS-406, INS NO.406, E-406, 232-658-1, B1033, Bengal, Vegetable gelatin, MFCD00081288, C14H24O9, Agar powder, Agar Powder, Gum-agar, orb2664825, GYYDPBCUIJTIBM-DYOGSRDZSA-N, SY062331, F245964 Agar, pure, powder Bacteriology and molecular biology grade (2R,3S,4S,5R)-2-(hydroxymethyl)-6-[[(4R,5S)-4-hydroxy-3-methyl-2,6-dioxabicyclo[3.2.1]octan-8-yl]oxy]-4-methoxy-tetrahydropyran-3,5-diolVEGITONE MACCONKEY AGAR NO 1;MACCONKEY AGAR CS;MAC CONKEY AGAR NO 1;MACCONKEY AGAR NO 1, VEGITONE;MACCONKEY BROMOCRESOL PURPLE BROTH;MACCONKEY BROTH PURPLE;MAC CONKEY MUG AGAR;MACCONKEY AGAR WITH MUG

Agar is a dried, hydrophilic, colloidal polysaccharide complex extracted from the agarocytes of algae of the Rhodophyceae. 
The structure is believed to be a complex range of polysaccharide chains having alternating a-(1!3) and b-(1!4) linkages. 
There are three extremes of structure noted: namely neutral agarose; pyruvated agarose having little sulfation; and a sulfated galactan. 

Agar can be separated into a natural gelling fraction, agarose, and a sulfated nongelling fraction, agaropectin.
Agar is a jelly-like substance consisting of polysaccharides obtained from the cell walls of some species of red algae, primarily from the Gracilaria genus (Irish moss, ogonori) and the Gelidiaceae family (tengusa).
As found in nature, agar is a mixture of two components, the linear polysaccharide agarose and a heterogeneous mixture of smaller molecules called agaropectin.

Agar 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.
The processing of food-grade agar removes the agaropectin, and the commercial product is essentially pure agarose.

Agar has been used as an ingredient in desserts throughout Asia and also as a solid substrate to contain culture media for microbiological work. 
Agar can be used as a laxative; an appetite suppressant; a vegan 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.

Chemically, agar consists mainly of agarose and agaropectin, which are linear and branched polysaccharides composed of repeating galactose units.
Agarose is primarily responsible for gel formation.
This structure gives agar its unique gelling properties.

Physically, agar appears as a white to off-white powder, flakes, or strips.
Agar is insoluble in cold water but dissolves in hot water, forming a gel upon cooling.
It is odorless and tasteless.

The compound exhibits strong gel-forming ability, creating firm gels even at low concentrations.
Agar forms thermoreversible gels.
This is important in food and laboratory applications.

Agar has a high gel strength and melting temperature, meaning gels remain stable at room temperature.
Agar solidifies around 35–45 °C and melts at higher temperatures.
This provides thermal stability.

Agar is chemically stable under normal conditions, though prolonged heating or extreme pH may cause degradation.
Proper storage ensures quality.
It should be kept dry.

Agar is widely used in food products, microbiological culture media, and pharmaceuticals.
Agar provides structure and stability.
This highlights its importance.

Agar is best described as a marine-derived polysaccharide with strong gelling, stabilizing, and thickening properties, widely used across food, scientific, and industrial applications.
Agar demonstrates excellent water-holding capacity, allowing it to retain large amounts of water within its gel network.
This prevents syneresis (water separation).

Agar shows good compatibility with sugars and acids, making it suitable for confectionery and acidic food systems.
It maintains gel structure in diverse formulations.
This increases versatility.

Agar can form brittle but firm gels, unlike elastic gels formed by some other hydrocolloids.
This characteristic is useful in specific applications.
Agar defines its texture profile.

The gelling behavior of agar is influenced by concentration, temperature, and ionic strength.
Adjusting these parameters changes gel strength.
This allows formulation control.

Agar is often used in combination with other hydrocolloids, such as locust bean gum or carrageenan, to modify texture.
These combinations improve elasticity or reduce brittleness.
This enhances functionality.

Agar exhibits high thermal stability, maintaining gel structure at room and moderately elevated temperatures.
This is important for processed foods.
It ensures consistent performance.

Melting point: 85–95 °C
bulk density: 720 kg/m³
FEMA: 2012 | AGAR (GELIDIUM SPP.)
storage temp.: room temp
solubility: H2O: 1.5% with heat
form: shredded
color: Brownish yellow
Odor: Odorless
pH Range: 5–7
pH: 6.5–6.8 (1.5% in gel, after autoclaving)
Odor Type: bland
biological source: synthetic
Water Solubility: SOLUBLE IN HOT WATER
Sensitive: Moisture Sensitive & Hygroscopic
Merck: 14,184
Stability: Stable. Incompatible with strong oxidizing agents
Major Application: agriculture

The Gelidium species amansii and cartilageneum are the major sources of agar, although many species of Rhodophyceae are used. 
The weeds (agarophytes) used in the commercial product of agar grow from the tide line out to depths of 120 ft, and are harvested by waders along the shore at low tide, raked from small boats or picked by divers. 
Because agar is soluble in hot water but relatively insoluble in cold water, it is extracted by boiling the agarophyte in water, filtering, cooling to form a gel, cutting into pieces and frozen, then thawing to free the agar from salts and other impurities that are soluble in cold water. 

The wet agar is repeatedly washed with cold water and finally dried. 
American and Japanese agar are graded according to published specifications. 
The high-quality American agar is divided into bacteriological, medicinal and dental grades, and the Japanese agar, into three grades and two subgrades. 

Agar is odorless or with a slight characteristic odor and mucilaginous taste. 
The structure of agar is not completely known. 
Chemically, agar is believed to be composed of 3,6-anhydro-L-galactose and D-galactopyranose residues in varying proportions.

An extract of certain species ofred seaweeds that is used as a gellingagent in microbiological culturemedia, foodstuffs, medicines, andcosmetic creams and jellies.
Nutrientagar consists of a broth made frombeef extract or blood that is gelledwith agar and used for the cultivationof bacteria, fungi, and somealgae.

Agar exhibits thermoreversible gelation, meaning it melts when heated and solidifies again upon cooling.
This process is repeatable without significant degradation.
Agar is important for laboratory and food uses.

The main component, agarose, forms a three-dimensional network structure in water.
This network traps water molecules.
This creates firm and stable gels.

Agar shows high gel strength even at low concentrations (≈0.5–2%).
Small amounts produce strong gels.
This makes it highly efficient.

Agar has a hysteresis between melting and gelling temperatures (melts ~85–95 °C, gels ~35–45 °C).
This provides stability at room temperature.
It prevents premature melting.

Agar is non-ionic, meaning it does not interact strongly with charged molecules.
This allows compatibility with many ingredients.
This increases versatility.

Agar is resistant to enzymatic degradation by most microorganisms, unlike some other polysaccharides.
This makes it ideal for microbiological media.
It maintains structure during incubation.

Agar exhibits good clarity in gels, especially purified agarose.
It forms transparent gels.
This is important in analytical applications.

Agar is low in calories and not digestible by humans, acting as a dietary fiber.
It passes through the digestive system largely unchanged.
This adds nutritional value.

Agar is a high-strength, thermoreversible, non-ionic gelling agent with excellent stability and clarity, making it essential in food, laboratory, and industrial applications.
Agar can form semi-solid and solid matrices, depending on concentration.
It is adaptable to different textures.

It is available in various grades (food grade, bacteriological grade, agarose) depending on purity and application.
Higher purity grades are used in scientific work.
Agar is a versatile hydrocolloid with strong gel formation, high water retention, and adaptable texture properties, making it essential across food, pharmaceutical, and laboratory fields.

Uses Of Agar:
Agar is the most suited solidifying agent for scientific applications that require incubation temperatures closer to human body temperature. 
Agar is used as a medium in bacteriology and plant biology, impression material in dentistry, biofertilizer in organic farming, and salt bridges in electrochemistry. 
It can be used to measure the motility and mobility of microorganism owing to the porous nature of the gel form of an agar or agarose medium.

Agar is a gum obtained from red seaweeds of the genera gelidium, gracilaria, and eucheuma, class rhodophyceae. 
Agar is a mixture of the polysaccharides agarose and agaropectin. 
Agar is insoluble in cold water, slowly soluble in hot water, and soluble in boiling water, forming a gel upon cooling. 

The gels are characterized as being tough and brittle, setting at 32–40°c, and melting at 95°c. 
Agar mainly functions in gel for- mation because of its range between melting and setting tempera- tures, being used in piping gels, glazes, icings, dental impression material, and microbiological plating. typical use levels are 0.1–2.0%.

Agar is widely used in the food industry as a gelling agent (E406).
It provides structure in products such as jellies, desserts, and confectionery.
This enhances texture and stability.

In confectionery products, such as gummy candies and jellies, it creates firm gels.
Agar helps maintain shape at room temperature.
This improves product quality.

Agar is applied in bakery fillings and glazes to provide consistency and prevent leakage.
It stabilizes formulations.
This enhances product performance.

Agar is used in dairy and plant-based alternatives, such as puddings and vegan desserts.
It acts as a plant-based gelatin substitute.
This supports vegan formulations.

In microbiology, it is used as a culture medium for growing bacteria and fungi.
Agar provides a stable surface for microbial growth.
This is essential in laboratory work.

It is applied in pharmaceutical formulations as a binder, laxative, and suspending agent.
It supports drug delivery and digestion.
This enhances functionality.

Agar is used in cosmetic products, such as creams and gels, as a thickening and stabilizing agent.
It improves texture and consistency.
This enhances product performance.

In food preservation and processing, it helps maintain structure and prevent water separation.
Agar stabilizes products during storage.
This improves shelf life.

Agar is also used in biotechnology and molecular biology (agarose gels) for DNA and protein separation.
It provides a gel matrix for electrophoresis.
This supports scientific research.

Agar is used wherever strong gel formation, stabilization, and structural support are required across food, laboratory, pharmaceutical, and cosmetic applications.
Agar is used in vegan and vegetarian food products as a plant-based alternative to gelatin.
It provides structure without animal-derived ingredients.

In instant desserts and powdered mixes, it helps form gels after heating and cooling.
Agar ensures consistent texture.
This improves convenience products.

Agar is applied in soups and sauces as a stabilizer and thickener.
Agar helps maintain uniform consistency.
This enhances product quality.

Agar is used in meat analogs and plant-based products to improve texture and binding.
It helps mimic the structure of traditional foods.
This supports product development.

In frozen foods and ice creams, it helps stabilize the matrix and reduce ice crystal formation.
Agar improves mouthfeel.
This enhances sensory properties.

Agar is applied in pharmaceutical capsules and controlled-release systems to form gel matrices.
It supports delivery of active ingredients.
This improves functionality.

Agar is used in wound dressings and biomedical applications due to its gel-forming ability.
It helps maintain moisture and structure.
This supports healing environments.

In cosmetic face masks and gels, it provides a firm, smooth gel texture.
Agar creates a film on the skin.
This improves user experience.

Agar is also used in plant tissue culture as a growth medium.
It supports development of plant cells and tissues.
Agar is used wherever firm gel formation, plant-based structuring, stabilization, and biomedical functionality are required across food, pharmaceutical, cosmetic, and research applications.

Safety Profile Of Agar:
Agar presents very low hazard potential, as it is a natural polysaccharide widely used in foods and laboratory applications and generally recognized as safe (GRAS).
It has a long history of safe use.
However, standard handling precautions are recommended for industrial forms.

Skin contact is typically low risk, but prolonged exposure to powder may cause mild dryness or irritation in sensitive individuals.
Molten agar (hot solutions) can cause thermal burns.
Protective gloves are recommended when handling hot material.

Eye contact may cause mild mechanical irritation.
Symptoms include redness and discomfort due to particulate matter.
Eyes should be rinsed with water if exposure occurs.

Inhalation of dust may cause minor respiratory irritation.
Fine powder can irritate the nose and throat.
Adequate ventilation and dust control are recommended.

Ingestion is considered safe at normal dietary levels, as agar is used as a food additive and dietary fiber.
Excessive intake may cause gastrointestinal effects such as bloating or laxative action.
Adequate water intake is recommended when consumed in larger amounts.

Agar is not highly flammable, but fine dust may present a dust explosion risk in confined industrial environments.
Proper dust management is required.
Agar is chemically stable under normal conditions, but prolonged heating or extreme pH can cause degradation.