Agar or agar-agar is a gelatinous substance derived from a polysaccharide that accumulates in the cell walls of agarophyte red algae.Historically and in a modern context, it is chiefly used as an ingredient in desserts throughout Asia and also as a solid substrate to contain culture medium for microbiological work. The gelling agent is an unbranched polysaccharide obtained from the cell walls of some species of red algae, primarily from the genera Gelidium and Gracilaria, or seaweed . Commercially it is derived primarily from Gelidium amansii.
Agar (agar-agar) can be used as a laxative, a vegetarian gelatin substitute, a thickener for soups, in jellies, ice cream and other desserts, as a clarifying agent in brewing, and for sizing paper and fabrics.
Chemically, agar is a polymer made up of subunits of the sugar galactose. Agar polysaccharides serve as the primary structural support for the algae's cell walls.
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 approximately 80% fiber, so it can serve as an intestinal regulator. Its bulk quality is behind one of the latest fad diets in Asia, the kanten (the Japanese word for agar-agar) diet. Once ingested,kanten triples in size and absorbs water. This results in the consumer feeling more full. Recently this diet has received some press coverage in the United States as well. The diet has shown promise in obesity studies.
In Philippine cuisine, it is used to make the jelly bars in the various gulaman refreshments or desserts such as sago gulaman (aka gulaman at sago), buko pandan, agar flan, halo-halo, the various Filipino fruit salads, black gulaman, and red gulaman. One use of agar in Japanese cuisine is anmitsu, a dessert made of small cubes of agar jelly and served in a bowl with various fruits or other ingredients. It is also the main ingredient in Mizuyōkan, another popular Japanese food. (See very top image.) In Indian cuisine, agar agar is known as "China grass" and is used for making desserts. In Burmese cuisine, a sweet jelly known askyauk kyaw is made from agar. In Russia it is used in addition or as a replacement to pectin in jams and marmalades, as a substitute to gelatin for its superior gelling properties, and as a strengthening ingredient in souffles and custards. The most famous use of agar-agar is in Ptich'ye moloko (Bird's Milk), a rich gellied custard (or soft meringue) used as a cake filling or chocolate-glazed as individual sweets.