寒天

Origin

Agar, also known as agar-agar, is a gelatinous substance derived from red algae, specifically species from the genera *Gelidium*, *Gracilaria*, and others. It is a complex mixture of polysaccharides composed of agarose and agaropectin. Agar was discovered in Japan in the late 17th century and has been used extensively in Asian cuisine and microbiology.

Usage

In the food industry, agar is primarily used as a thickening agent, gelling agent, stabilizer, and texturizer. It is employed in a wide variety of products, including desserts, jellies, puddings, ice cream, processed cheeses, and vegetarian gelatin alternatives. Agar has a high gelling strength, even at low concentrations (typically 0.5-2%), and forms a firm, brittle gel that is heat-resistant and reversible. It is also used in confectionery, bakery products, and as a clarifying agent in brewing. Beyond food, agar is a crucial component in microbiology as a solidifying agent in culture media for growing bacteria and fungi.

Side Effects

Agar is generally considered safe for consumption. It is poorly absorbed in the digestive tract and acts primarily as a dietary fiber. High doses of agar may cause mild gastrointestinal discomfort, such as bloating or diarrhea, due to its bulking effect. Allergic reactions to agar are rare, but individuals with known allergies to red algae should exercise caution. There is no established Acceptable Daily Intake (ADI) for agar, indicating its low toxicity. Regulatory bodies like the EFSA and FDA have generally recognized agar as safe for its intended uses in food.

Regulatory Status

Agar is approved for use as a food additive in many countries, including the United States, the European Union, and Japan. In the EU, it is designated as E406. The FDA considers agar to be Generally Recognized As Safe (GRAS) under specific conditions of use. The safety of agar has been evaluated by various scientific bodies, including the Joint FAO/WHO Expert Committee on Food Additives (JECFA), which has not established a numerical ADI due to its low toxicity.