Formation of pyrrolidino[1,2-e]-4H-2,4-dimethyl-1,3,5-dithiazine in the volatiles of boiled short-necked clam, clam, and corbicula

Abstract

The characteristic odor constituents from boiled short-necked clam, clam, and corbicula were investigated. Some distinctions in the composition of sulfur- and/or nitrogen-containing substances were observed among the shell fish species. Pyrrolidino[1,2-e]-4H-2,4-dimethyl-1,3,5-dithiazine(I), which is a common component from cooked small shrimp, was also found in clam and corbicula. The presence of a large quantity of compound I should contribute a roasted odor to the taste of boiled corbicula. Compound I possesses an extremely low odor threshold. 1-Pyrroline and compound I were produced at the same time during heating and were increased by longer heating. It is postulated that compound I was formed secondarily from 1-pyrroline with ethanal and hydrogen sulfide in the shellfish during heating.