Agar

Agar called ( from Malay ), also Agar - agar, Agartang, Japanese isinglass, edges ( Japanese), or Chinese or Japanese gelatin, is a galactose polymer ( a polysaccharide ), can form the curd. The basic units of the agar is agarose and sulfated agaropectin.

Agar is prepared from the cell walls of some species of algae (especially red algae such as Gracilaria, Gelidiopsis, Gelidium, Hypnea and Sphaerococcus species ), mainly from East Asia.

Properties

Agar is tasteless and indigestible. It is a very good gelling agent that is independent of the ambient medium. Even a concentration of 1%, dissolved in hot water, enough for a resilient, sufficiently mechanically stable but not too solid gel with a very thin layer of aqueous fluid to the surface (formed by syneresis ). Half a teaspoon corresponds to about four sheets of gelatin. The thin layer of aqueous liquid to the surface of the gel allows sliding of solid objects, to the gel surface. This is a uniform distribution of material with a solid object made ​​of glass or metal (usually a Drigalskispatel or inoculating loop ) on the gel surface possible. Agar gel is liquid at 95 ° C., so that the gel is stable at temperatures higher than those of gelatin gels, and frozen at 45 ° C, whereby the addition of thermally unstable materials can be before setting.

Areas of application

In the food industry, agar is used ( in the EU as a food additive under the number E 406 ) as a thickening agent, such as soups, confectionery and ice cream, however, is relatively rare, because the price is relatively high. In the household can use it as a vegan substitute for gelatin. In Japan and China Agar is used since the 17th century for the preparation of food. In Southeast Asia, it is an integral part of the kitchen. There, it is used to prepare a variety of desserts. Gelatin is completely unknown there.

In microbiology culture media for microorganisms are almost invariably solidified with agar instead of the one used by the end of the 19th century gelatin because agar resistant to that used with the sterilization high temperature than gelatin, gelatin gels are liquid at higher incubation temperatures and because some microorganisms can digest gelatin. The German microbiologist Walther Hesse was the first of the agar culture media used for cultivating bacteria and this published in 1884. The idea came from his wife Fanny Angelina Hesse, the agar used for the production of fruit and vegetables in aspic jelly.

In molecular biology, agarose is used as the matrix for the separation of nucleic acids by gel electrophoresis.

Agar in gel form is used as a substrate for various plants for the breeding laboratories. It is shown in comparison to other gelling agents, such as Gelrite that these funds are not inert in the cultivation, but also influence the physiology of, for example, plant cell cultures.

Because of indigestion agar is used ( in higher doses than in foods ) as a laxative. In Indonesia, agar-agar is attributed positive effects against diabetes and heart disease.

Where to Buy

Agar is available in large supermarkets, health food stores, health food stores and Asian grocery stores. Agar in pure form can be purchased in pharmacies.