Crab foam - Crab foam

...This deterioration is accelerated by light, metal, and temperature, so it is best to store the oil in a cool, dark place, seal the container as tightly as possible after opening, and use it up as soon as possible. When frying food repeatedly in the same oil, it can cause smoke, discoloration, and an increase in viscosity, and eventually the formation of fine, persistent bubbles (crab foam); these are collectively called oil deterioration. The main cause of this is high-temperature heating, so to reduce it, it is necessary to avoid heating above the appropriate temperature and unnecessary maintenance of high temperatures.

*Some of the terminology that refers to "crab foam" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…これは光，金属，温度により促進されるので冷暗所に保存し，開封後も容器はなるべく密栓し，早く使いきるのが望ましい。同じ油でなん回も揚物をすると発煙，着色，粘度の増加があり，ついには細かい持続性の泡(カニ泡)を発生するが，これらを総称して油の劣化という。この主因は高温加熱であるから，これを少なくするには，適温以上の加熱と高温の不要な保持を避ける必要がある。…

※「カニ泡」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報