When clams are boiled, the soup becomes cloudy, but until now it was not clear why it turned white.In Shimane Prefecture, which has Lake Shinji, which is known as a clam production area, it was clarified that the causative agent of cloudiness is the protein tropomyosin.A research group at Shimane University found out by using methods such as separating and detecting proteins in clam juice.
In the research, we first found that the causative agent of cloudiness is relatively large (100 kDa or more).Speaking of large macromolecules, it is highly likely that they are proteins. "to absorb" did not apply.
Therefore, we separated the protein from clam juice by SDS-PAGE (polyacrylamide electrophoresis) and further analyzed it by MALDI-TOFMS (matrix-assisted laser desorption/ionization). pinned down.
The cloudiness of milk is related to the binding of calcium to a protein called casein, and the cloudiness of tonkotsu soup is related to lipids in addition to proteins.I also examined tropomyosin of freshwater clams, but ions such as calcium and lipids were irrelevant.
On the other hand, it was found that clams, scallops, oysters, and other shellfish other than clams became cloudy when boiled, and the causative agent was tropomyosin.
Regarding the fact that tropomyosin did not satisfy the characteristics of heat denaturation and ultraviolet absorption, it is said that tropomyosin has heat resistance even among proteins that are generally sensitive to heat, and that tropomyosin contains an amino acid called tryptophan that absorbs wavelengths of 280 nm. It became clear that no
Tropomyosin itself does not have a delicious taste and is not considered to be involved in the deliciousness of clam juice, but it is possible that tropomyosin can be used to make cloudy soup to make it look “delicious”. .
Paper information:[Scientific Reports] Tropomyosin micelles are the major components contributing to the white color of boiled shellfish soups
