Author: Site Editor Publish Time: 2022-01-24 Origin: Site
Agar or agar-agar is a jelly-like substance, obtained from red algae.There are crystal powder and stripes two types.
Agar is a mixture of two components: the linear polysaccharide agarose, and a heterogeneous mixture of smaller molecules called agaropectin.It forms the supporting structure in the cell walls of certain species of algae, and is released on boiling. These algae are known as agarophytes, and belong to the Rhodophyta (red algae) phylum.
1:Agar may have been discovered in Japan in 1658 by Mino Tarōzaemon, an innkeeper in current Fushimi-ku, Kyoto who, according to legend, was said to have discarded surplus seaweed soup 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.
2: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.
3:Beginning in the late 19th century, agar began to be used heavily 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 Fannie 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.
Agar-agar is a natural vegetable gelatin counterpart. White and semi-translucent, it is sold in packages as washed and dried strips or in powdered form. It can be used to make jellies, puddings, and custards. For making jelly, it is boiled in water until the solids dissolve. Sweetener, flavouring, colouring, fruit 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 jelly layer in a cake.
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.
An agar plate 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. Agar 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.
2:As a medium to precisely orient the tissue specimen and secure it by agar prepare-embedding for histopathology processing.
4:In formicarium as a transparent substitute for sand and a source of nutrition.
5:As a natural ingredient to form modelling clay for young children to play with.
6:As an allowed biofertilizer component in organic farming.