Agar (agar-agar, E406) is a gelling agent that is obtained from naturally occurring marine algae. therefore its other name is "sea gelatin". Thanks to its gelling properties, agar has been widely used in the food industry, not only. Check if the agar is he althy and what to use it.

Agar , also known asagar-agarorE406 , is a natural substance of plant origin, which is used in industry and households as a gelling and thickening agent. It is a component of the cell walls of marine algae, and more specifically algae from the Rhodophyta family. Agar belongs to polysaccharides or polysaccharides. It is a mixture of agarose and agaropectin.

Agarose constitutes about 70% of the agar composition and its gelling ability depends on its content. Agarose is a large linear molecule composed of alternating monosaccharide units: D-galactose and 3,6-anhydro-L-galactose. The ratio of agarose to agaropectin varies depending on the type and species of seaweed used to produce the agar.

Different varieties of agar have different gel strength and gel stiffness. In addition, the content of agarose and agaropectin in plant cell walls depends on the season and hydrodynamics of the environment, i.e. water movements.

Agar (agar-agar, E406) - properties

Agar is most commonly available as powder, leaves, cubes or threads. Powdered material is used in industry, and the remaining forms are used for cooking dishes. It is colorless, has no taste and no smell.

Dissolves very well in boiling water. However, it does not dissolve at all in cold water and alcohol. Agar swells in cold water, dissolves at 85 ° C, and on cooling it solidifies at 34-43 ° C, forming a gel solid resembling a chilled jelly.

Does not melt again up to 85 degrees C. Agar's gelling properties depend on the pH of the solution. In acidic products they decrease.

Why is agar an industry-valued gelling agent?

  1. Its high gelling ability in an aqueous environment allows it to create gels that are much stronger and more resistant than the gels of any other gel former, while maintaining the same concentrations.
  2. Plain aqueous agar has the capacitygelling. No additional reagents such as potassium or proteins added to carrageenans or calcium added to alginates are needed.
  3. There is no need to raise the concentration of sugars or maintain an acidic pH as is the case with pectins.
  4. It can be used in both acidic and alkaline solutions, usually in the pH range from 5 to 8.
  5. It is resistant to temperatures above 100oC, which enables sterilization of products.
  6. 1.5% aqueous solution gels between 32 ° C - 43 ° C and does not melt below 85 ° C. This is a unique property of agar compared to other gelling agents.
  7. Agar gives no flavor to products and can be successfully used in foods with a very delicate taste.
  8. It absorbs and enhances the flavor of the products to which it is added. Works as a fragrance fixative.
  9. It can be gelled and melted many times without losing its original properties.
  10. It allows to obtain transparent gels and is easy to color.

Agar (agar-agar, E406) - application

Agar is used in the food industry as a gelling, stabilizing and viscosity controlling agent. It is marked with the symbol E 406. It is a food additive, not a nutrient, because the human body digestes it only in 10%. Agar's gelling ability is so great that it is used in a maximum concentration of 1.5%, so its consumption is very low.

Agar is the longest-used colloid derived from plants. It has been used as a food additive in the Far East for over 300 years, and in Western countries for over 100 years. It is a completely safe food additive. This is confirmed by its many years of use, as well as opinions issued by expert groups from FAO / WHO and FDA.

In what foods can agar be used?

  • sweets: jellies, marshmallows, candies, candy and cookie fillings
  • in marmalade.
  • in baking to coat cookies and prevent them from drying out
  • chocolate
  • in yoghurts with a slightly sweet taste without the acidity typical of yoghurts
  • in ice cream, milk drinks, puddings, puddings
  • in cheese and other dairy products
  • in low-fat sausages and frankfurters, where it acts as a binder instead
  • in canned meat
  • in sauces and broths
  • in liqueurs with alcohol
  • for wine clarification
Worth knowing

Agar can be used in cooking and baking instead of gelatin. It works well in the preparation of fruit and meat jellies, cheesecakescold or desserts. It is a vegetarian product. It sets a little faster than gelatin. It surpasses it in that it has no taste and smell and is transparent.

Different types of agar show different gelling strength, so always read the label. The amount of agar equivalent to 1 teaspoon of gelatin is 1/2 to 2 teaspoons. In a more acidic environment, you can add a little more as it gels less.

Apart from the food industry, agar's gelling properties are also used. It is mainly used as a substrate for the growth of microorganisms in microbiological laboratories. In addition, 8% agar solution is used to make casting molds, it is used in sculpture and archeology. Agar is also used in making dental castings.

Agar-based molds are more expensive than others, but much more accurate. In the production of pharmaceutical preparations, agar is used as a filler. It is also known as a laxative that swells in the intestines and facilitates bowel movements with plenty of water. It can be counted among the soluble fractions of dietary fiber.

Agar is used in plant nurseries, in the cloning technique, incl. orchids. Agarose - the main component of agar is used in biochemistry and biotechnology. It can be used for protein separation, biotechnological production of insulin, interleukin and others, diffusion techniques, chromatography and electrophoresis.

Worth knowing

Agar (agar-agar, E406) - history

Agar comes from Japan, where it was discovered in 1658 by the innkeeper Tarazaemon Minoy. There is a legend that he discovered agar after cooking red algae soup, which turned into jelly when cooled. In the 17th and 18th centuries, agar spread to other Asian countries, where it became an important part of local cuisine.

It came to Europe in 1859 thanks to the French chemist Anselm Payen, who distributed it as a Chinese food item. In 1882, the assistant of Robert Koch, microbiologist W alter Hesse described the possibilities of using agar as a medium for the cultivation of microorganisms in microbiological laboratories. Since then, his popularity in the Western world has skyrocketed.

Until the Second World War, almost all agar production was concentrated in Japan. Spain and Chile became the next large agar-producing centers.

Agar (agar-agar, E406) - how is it obtained?

Originally, agar was obtained from red algae of the genus Gelidium, and it was this seaweed that was the source of the agar with the strongest gelling properties. The other types gave a product of worse qualityproperties, which is why they were called agaroids. Nowadays, all these gelling agents are called agar, but very often the name of the type of seaweed from which it was obtained is added to the word "agar" in the name. In various regions of the world, other red algae are used to produce agar:

  • Gelidium (various species) in Spain, Portugal, Morocco, Japan, Korea, Mexico, France, USA, China, Chile and South Africa;
  • Gracilaria (various species) in Chile, Argentina, South Africa, Japan, Brazil, Peru, Indonesia, the Philippines, China, India, and Sri Lanka;
  • Pterocladia capilace in the Azores and Pterocladia lucida in New Zealand;
  • Gelidiella in Egypt, India and Madagascar.

Seaweed is grown in underwater farms. Different types require a different substrate. For example, Gelidium grows best on rocky ground and Gracilaria - sandy.

  • Traditional method of obtaining agar

Krasnorosty is collected, washed and sorted by hand to separate mechanical impurities and other seaweed. Then it is boiled in boiling water with the addition of vinegar or sake. The extract is filtered hot through a cotton cloth, poured into wooden trays and cooled to gel.

Gel, cut into rectangular bars or extruded as spaghetti-like threads, is spread over bamboo sieves and left for 1 or 2 nights to fully concentrate in the open air, facing north winds. Once concentrated, the gel is sprinkled with water throughout the day to dissolve. The agar is then dried in the sun.

The traditional method of obtaining agar is now rarely used by Japanese artisans and is of marginal importance compared to global industrial production. Traditionally obtained agar does not have reproducible properties that are extremely important in large-scale production processes.

  • Industrial method of obtaining agar

After harvesting, the seaweed is washed and cleaned, then dried to avoid agar-destroying fermentation. They are then pressed with a hydraulic press, which reduces their volume and therefore transport costs. The agar production process from Gelidium and Gracilaria is slightly different, as Gracilaria has many more sulfuric acid residues which reduce the agar's gelling ability.

Gelidium is heated in a mild sodium carbonate solution to remove dyes. Gracilaria, on the other hand, is treated with a sodium base at a concentration of 0.5 to 7% in order to desulphate and then wash. Next stages, following stagesapply to all red algae.

These include extraction, i.e. the extraction of agar from the seaweed cell walls, filtration, i.e. purification of undesirable ingredients, and gelling by freezing.

Gelidium agar is thawed and frozen several times and then whitened. With Gracilaria agar, the freeze-thaw stage is omitted, but syneresis is performed, which results in the formation of a very concentrated gel. The agar is then dried and ground.

Sources: 1. Armisen R., Galatas F., Agar, in: Handbook of Hydrocolloids, 2009, http://sgpwe.izt.uam.mx/pages/cbs/epa/archivos/quimalim/agar .pdf 2. Armisen R., Galatas F., Production, properties and uses of agar, http://www.fao.org/docrep/x5822e/x5822e03.htm 3. PubChem, Agar, https: //pubchem.ncbi .nlm.nih.gov / compound / 71571511 4. https://www.researchgate.net/figure/Flow-diagram-for-agar-production_fig1_286013969 5.http: //karmel-itka.blogspot.com/2015/04 /zelatyna-vs-agar-poksramiamy.html

About the authorAleksandra Żyłowska-Mharrab, dietician Food technologist, dietitian, educator. A graduate of Biotechnology at the Gdańsk University of Technology and Nutritional Services at the Maritime University. A supporter of simple, he althy cuisine and conscious choices in everyday nutrition. My main interests include building permanent changes in eating habits and individually composing a diet according to the body's needs. Because the same thing is not he althy for everyone! I believe that nutritional education is very important, both for children and adults. I focus my activities on spreading knowledge about nutrition, analyze new research results, and make my own conclusions. I adhere to the principle that a diet is a lifestyle, not strict adherence to meals on a sheet of paper. There is always room for delicious pleasures in he althy and conscious eating.

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