Seasonal Variations in the Sterol, Fat and Unsaponifiable Components of Scallop Muscle

Abstract

The total fats, unsaponifiable material, provitamins D, and sterols were determined on monthly samples of male and female sea scallop, Placopecten magellanicus (Gmelin). During the pre-spawning period (August), total fat, unsaponifiable, and sterol levels were low indicating an active transfer of these materials to the gonad tissue. During the retarded growth period (February, March), the fat content of the muscle decreased but there was a compensating increase in the unsaponifiable and sterol content of the total fat. The composition of the sterol fractions was determined by gas chromatography. The principal sterol components of the scallop muscle were found to be 22-dehydrocholesterol, cholesterol, brassicasterol, and 24-methylenecholesterol. Changes in the composition of the sterols were not as extreme as those reported in the literature for some other shellfish. However, variations in the cholesterol and 24-methylenecholesterol content of the scallop muscle suggested a relationship in the metabolism and biosynthesis of these sterols. There were no obvious differences in the composition of the muscle of male and female scallops.