آگار
| EC number | 232-658-1 |
| HS Code | 13023100 |
| Storage | store at 15 to 30 C |
| SDS | available |
| RTECS | AW7950000 |
| Odour | odourless |
| Form | solid |
| Color | brownish to yellow |
| p H value | 6.8 (100 g/l 20°c) |
| Solubility in water | 20 g/l (60°c) |
| Melting point | 90 °C |
| Description | Conforms | ||
| Identification | Conforms | ||
| Swelling value | 12 to 14 | ||
| Insoluble substances | ≤ | 1 | % |
| Gelatin | Conforms | ||
| Ash | ≤ | 5 | % |
| Loss on drying | ≤ | 20 | % |
Agar is a gelatinous substance derived from red algae, widely used in microbiology, food industry, and molecular biology due to its gelling, stabilizing, and thickening properties.
🏭⚗️ Production
Agar is obtained by boiling specific species of red algae, particularly from the genera Gelidium and Gracilaria. The extraction process involves boiling the algae in water to release the polysaccharides, followed by filtration and purification. The resulting solution is then cooled to form a gel, which is pressed, dried, and ground into flakes or powder depending on its final use.
🔬 Properties
Agar is a mixture of two polysaccharides: agarose and agaropectin. It is typically white or slightly yellowish in color and is odorless and tasteless. Agar has the unique property of melting at around 85 °C and solidifying between 32–40 °C, making it ideal as a thermal-stable gel. It is insoluble in cold water but dissolves readily in boiling water, forming a firm gel upon cooling. Agar is indigestible by most organisms, including humans.
🧪 Applications
Agar is extensively used in microbiology as a culture medium for growing bacteria, fungi, and other microorganisms due to its stable gel formation and resistance to microbial degradation. In the food industry, it functions as a vegetarian alternative to gelatin and is used as a thickener in desserts, jellies, ice cream, and canned foods. In molecular biology, purified agarose derived from agar is used for gel electrophoresis to separate DNA and RNA fragments. Agar also finds applications in cosmetics, pharmaceuticals, and traditional Asian cuisine.
⚠️ Safety
Agar is generally regarded as safe and non-toxic for both laboratory and food use. However, inhalation of fine agar powder may cause respiratory irritation, especially in industrial or laboratory settings. It should be stored in a dry, cool place and handled in well-ventilated areas when in powdered form. Although not digestible, agar can absorb water and swell in the digestive tract, so excessive intake may lead to gastrointestinal discomfort.
