Agar-Agar

Agar-agar, known as just agar in culinary circles, is a plant-based gelatin derived from seaweed. The white and semitranslucent vegetable gelatin is sold in flake, powder, bar, and strand form, and can be used in recipes as a stabilizing and thickening agent.

Agar is nondigestible. It is used in food products where its emulsifying, stabilizing, and gelling properties and the heat resistance of its gel are useful.
In sherbets and ices, agar–locust bean gum–gelatin is superior with respect to texture, syneresis, incrustation, and flavor stability. The optimum stabilizer concentrations have 0.12% of agar, 0.07% of locust bean gum, and 0.20% of gelatin.
Agar is employed at levels of 0.05–0.85% in Neufchatel-type processed and cream cheeses and in fermented milk products, such as yogurt. Improved texture and stability are conferred.
In confectionery, agar jelly candies are staples; fig–agar and marshmallows are leaders. In South America, a sweet potato–sugar–agar confection has wide popularity. Agar percentage varies with the texture desired; 0.03–1.8% is common.
Manufacturers of baked goods use agar in cookies, cream shells, piping gels, pie fillings, icings, and meringues as an antitackiness ingredient. It has been used with success as an antistaling agent in breads and cakes. The range of concentration is 0.1–1%.
The use of agar is well established in vegetarian and health food products, including prepared cereals, meat substitutes, and desserts.
Poultry and meat canners employ agar as a gelling agent at 0.5–2.0% of the broth weight, thereby eliminating transit damage of fragile tissues.
Fast Facts
Also Known As: Kanten
Sold As: Powder, flakes, bars, and strands
Use: Vegetarian substitute for gelatin
This jellylike substance is a mix of carbohydrates that have been extracted from red algae, a type of seaweed. Agar has several uses in addition to cooking, including as a filler in sizing paper and fabric, a clarifying agent in brewing, and certain scientific purposes. It is also known as China glass, China grass, China isinglass, Japanese kanten, Japanese gelatin, and dai choy goh, and is used in certain Japanese dessert recipes.
Origin
Agar has its origins in Japan in 1658. It was introduced first in the Far East and later in the rest of agarophyte seaweed producing countries. Its use was introduced in Europe in 1859 and it was being used in bacteriological culture media in 1882. This chapter discusses the seaweeds used the world over as raw material for agar production (agarophyte seaweeds), and presents the industrial processes used for agar production. The chemical structure of agar and its fractions, such as agaroses and agaropectines, are presented, and the relation between its chemical structures and properties are also shown.
Agar-Agar vs. Gelatin
The main difference between agar and gelatin is from where they are derived. Whereas animal-based gelatins are made from livestock collagen (from the cartilage, bones, skin, and tendons), agar-agar is purely vegetarian, coming from the red algae plant. The two setting agents also behave differently and need to be prepared in distinct ways when incorporating into a recipe. Agar-agar needs to boil in order to set, while gelatin can simply dissolve in warm water; that is because agar melts at 185 F, whereas gelatin melts at 95 F. Agar also sets more quickly than gelatin and doesn't need any refrigeration.
The resulting recipe will also have subtle variances: Dishes made with agar will be firmer and less creamy and jiggly than those made with gelatin. Agar-agar recipes also stay firm when exposed to higher temperatures, while gelatin loses some of its stability.
The gelation and melting of agar and its fractions, such as agaroses and agaropectines, is based only in the formation of hydrogen bridges (physical gels), and thus gelation is extraordinarily reversible. The synergies and antagonisms among agar and other products in the gelation processes are studied. Various applications of agar are presented, in some of which agar is irreplaceable. Use formulations are shown in food preparations. Diverse applications are also presented, in the preparation of food for insects, for plant tissue culture, and in the preparation of culture media for microorganisms, as well as gels for denture moulding, the reproduction of archaeological remains or of fingerprinting in police work. Agar gels are important in food preparations with high content in soluble gross fibre, as agar is the food additive with the highest content in said fibre, superior to that of 94%. Lately the production of more easily soluble agars in water at temperatures below boiling point has been initiated, which proves to have noteworthy advantages for some of its applications. A comparative study is presented among the commercial products existing in the world market.
Varieties
Agar-agar is sold as flakes, powder, bars, and strands. The seaweed is typically boiled into a gel, pressed, dried, and then crushed to form agar flakes, blended into a powder, freeze-dried into bars, or made into strands. The powder is less expensive than flakes and the easiest to work with as it dissolves almost immediately, whereas the flakes take a few minutes and need to be blended until smooth. The powder is also used in a 1:1 ratio when substituting for gelatin—when using flakes, 1/3 the amount of gelatin called for should be added. The agar bars, sticks, and flakes can be processed into powder form in a blender or food processor. Similar to gelatin, flavored and colored versions of agar are available.
Agar-Agar Uses
In cooking, agar-agar is used as a vegetarian alternative to gelatin in a variety of dishes, including puddings, mousses, and jellies, as well as ice cream, gummy candies, and cheesecake. It is an important ingredient in the Japanese dessert anmitsu, which calls for kanten jelly, a mixture of agar-agar, water, and sugar.
How to Cook With Agar-Agar
Before agar can be added to a recipe, it needs to be dissolved in water and then boiled; it cannot be simply dissolved in a liquid or added directly to food. Dissolve the agar in a liquid in a small saucepan over medium-high heat, bring to a boil, and then simmer until slightly thickened, about five to seven minutes. Agar powder dissolves more quickly than flakes and strands, which need extra soaking time and stirring to fully dissolve. (Flakes, bars, and strands can be processed into powder before using.)
To use agar flakes in a recipe, measure 1 tablespoon for every cup of liquid; for agar powder, use 1 teaspoon to thicken 1 cup of liquid. (The general rule of thumb when substituting agar for gelatin is to use an equal amount of agar powder and one-third the amount of flakes as gelatin.) Once the dissolved agar is added to a recipe, it will take approximately an hour to set at room temperature. Most recipes using agar are eaten cold so the dish will need to be refrigerated.
It is important to note that foods high in acidity, such as citrus fruits, strawberries, and kiwi, may require additional amounts of agar to fully gel.
What Does It Taste Like?
Agar-agar is completely odorless and tasteless, making it an ideal gelling agent for adding to any type of recipe.
Agar-Agar Substitute
Of course, gelatin can be substituted for agar, but if a vegetarian alternative is needed, there are a few other options to consider. One is another type of seaweed called carrageen, which is used to produce carrageenan, a thickening agent extract. It sets more softly than gelatin, and it's best to use the whole dried form versus the powder. The dried seaweed should be rinsed well and soaked for 12 hours in water and then boiled and strained out. One ounce of carrageenan should be used per 1 cup of liquid.
Pectin powder, derived from citrus fruit and berries, is often used to thicken jams and jellies and can be used in place of agar. It does include sugar, so it is best in sweet recipes. A manufactured product available from a variety of brands is an unflavored vegan gel, a vegetarian gelling powder that is a combination of a variety of ingredients including carrageenan.
Agar-Agar Recipes
Any recipe that calls for gelatin, from jello shots to panna cotta, is a good candidate for using agar, as long as the proper ratios are followed.
Anmitsu: A Classic Japanese Dessert
Vegan Raspberry Champagne Gelée
Double Fruit Jelly Candies (substitute agar for the gelatin)
Where to Buy Agar-Agar
Agar-agar can be found in the natural food section of the supermarket, health food stores, Asian groceries, and online. Agar flakes are more expensive than the powder (and gelatin), but less is needed in recipes. Agar strands are the least expensive option.
Food Science Basics: Healthy Cooking and Baking Demystified
Agar (agar agar) is a gelatinous substance that is extracted from seaweed and processed into flakes, powders and sheets. It is commonly used in Asian cuisines and as a flavorless vegan substitute for gelatin. Agar helps gel, stabilize, texturize and thicken beverages, baked goods, confectioneries, dairy products, dressings, meat products and sauces.
Agar gels at low concentrations; the gel is opaque in color and chewy in texture, making it versatile in both cold and hot dishes. A general rule of thumb is to use 1 tablespoon of agar flakes or 1 teaspoon of agar powder to thicken 1 cup of liquid.
Additives: phosphates, salts (sodium chloride and potassium chloride, citrate, lactate) and hydrocolloids
Agar-agar originates from the Malay name ‘gel-building food from seaweed’. Agar is a polymer of agarobiose, which is a disaccharide made from galactose and 3,6-anhydrogalactose. It is a creamy white powder which is soluble in hot water but insoluble in cold water.
Formation of gel starts to take place at a concentration of 0.4% and a temperature above 80 °C fully dissolves agar. Upon cooling below 40 °C a gel is formed. Hence, the gel is thermoreversible, meaning that the gel becomes liquid again upon the impact of heat. Agar-agar, a substance high in dietary fibre (80 g per 100 g), is widely used in the bakery industry, but is also used in retorted meat products such as canned corned beef. Gels made from agar-agar show a high degree of syneresis.
Food additives
Agar is a galactose-based heterogenous polysaccharide derived from red algae. It is a heterogenous polysaccharide composed of agarose and agaropectin polymers. Agar is best known as the growth media used in identification and enumeration of microbial organisms. Agar gels are reversible (melts at 85°C and solidifies at 32–40°C) and translucent. Refined grades of agar are used in food applications. Agar's properties are similar to gelatin. It is a good substitute for animal-based gelatin in vegetarian foods. Agar is easier to use in food gels than many other substances. Common food applications of agar include puddings, custards, and soft candies. Agar improves the texture of processed cheese and frozen desserts. It is also added to baked goods to inhibit staling. A creative food application uses agar-based gel cubes that are infused with fruit extract or wine to make a vegetable-based aspic. You may have encountered agar in the dentist's office where it is often the polymer used to make dental impressions.
Polymers in Biology and Medicine
Agar is the most commonly used growth medium for microorganisms. Due to the ease with which agar can be transported (dry, dissolved, and gelled), it is ubiquitous in the modern-day laboratory. Solid agar plates can support microbial growth when supplemented with appropriate nutrients or be used for antibiotic selection. Agar media is essential for the study of microorganisms and molecular biology and is widely used in the culture and detection of pathogens from contaminated food and water.173 In addition, due to its porous 3D framework, agar is frequently used in biomolecular separation and purification. Agar is one of the most common basic media for gel electrophoresis, gel bead chromatography, and size exclusion chromatography.174–176
In addition to its use as a solid growth media, agar has been fabricated in different forms (e.g., microspheres and films) to encapsulate molecules for sustained-drug delivery177 or immobilize proteins for tissue engineering.178 Due to the gelation property of agar, it is most often used as a hydrogel. To realize sustained-drug delivery, agar hydrogels have been modified by integrating other biopolymers to form an interpenetrating network. This network structure of agar hydrogels is able to improve the mechanical property of the drug delivery systems and also extend the drug release profile.179 in tissue engineering, agar hydrogels with high porosity have shown promising results to promote cell adhesion and proliferation.180
Carrageenans
Agar is a thermoreversible gelling agent composed of two polysaccharides. Agarose (or agaran) is a linear chain of 3-O-substituted β-d-galactopyranosyl units joined by (1 → 4) linkages to 3, 6-anhydro-α-l-galactopyranosyl units. (Note that the anhydrosugar in agar has the L configuration.) Agarose is the gel-forming component. Agaropectin is a branched, nongelling component of agar. Small amounts of sulfate half-ester groups and pyruvate 3,6-cyclic acetal groups (Chapter 2) may be present. Considerable amounts of methyl ether groups are also present. These structural characteristics make agar the least hydrophilic and least water soluble of the red seaweed polysaccharides. Usually, agar can only be dissolved in water at 100°C (boiling) or higher temperatures, although preparations that hydrate and dissolve at about 80°C are available (with and without standardizing materials).
The principal use of agar is in bakery icings and frostings because it is compatible with large amounts of sugar and its products neither melt at high storage temperatures (such as might be found in a delivery truck) nor stick to the packaging material. It is also used in light sour cream, no-oil salad dressings, and yogurt. Its use is limited by its high price. Agar may be designated agar or agar–agar on product labels.
Fungi | Foodborne Fungi
AFPA cannot be used to screen for aflatoxin production, but coconut cream agar (CCA) can be used to detect aflatoxin production in A. flavus and A. parasiticus. CCA is made using any brand of commercial canned coconut cream. Dilute 50:50 with water, add agar (1.5%), and autoclave. Inoculated CCA should be incubated at 25–30 °C for 5–7 days. Examine colonies, reverse upmost, under a long-wave length ultraviolet (UV) light. Colonies producing aflatoxins fluoresce bluish white or white, especially in the centers. An uninoculated CCA plate can be used as a control, but a plate inoculated with known nontoxigenic and toxigenic strains provides a better comparison.
Is agar agar vegan
Given that agar agar is purely derived from plant-based ingredients, it is a vegan product and suitable for use in all vegan recipes.
Storage
All forms of agar-agar should be stored in an airtight container in a cool, dry spot such as the pantry, where it will last at least eight months.