Crystallization of Tyrosine in Shiokara made of Japanese Firefly Squid (Watasenia Scintillans, BERRY)

Abstract

White crystal or sediment that often found in Shiokara made of firefly squid (Watasenia scintillans, BERRY) during the refrigeration causes unpleasantness for consumers. Amino acid analysis and microscopic study proved that the crystal or sediment in Shiokara is due to the crystallization of tyrosine. Tyrosine contents, as a free amino acid, in mantle, arm, liver and ovary of firefly squid were 26, 23, 237 and 45mg/100g, respectively. Tyrosine in the liver of firefly squid was thought to be the major cause of the white crystal or Sediment in Shiokara because of its solubility in cold water, 40mg/100ml at 17°C.