Abstract
The determination of cholesterol concentration in corb shell (shijimi), bloody clam (akagai), shortneck clam (asari), clam (hamaguri), and oyster (kaki) has been described. Colorimetric, enzymatic, and gas-liquid chromatography (GLC) method are employed for the determination. Results could be summarized as follows.
1. Color of the extract was yellow and its maximum absorption was shown at 450 to 460nm.
2. Concentration of cholesterol was determined by Liebermann-Burchard reaction, Killiani reaction, OPA reaction, and enzymatic reaction. The results were 216mg/100g for shijimi, 160 for akagai, 115 for asari, 113 for hamaguri, and 153 for kaki by Liebermann-Burchard reaction and 174, 124, 100, 93, and 154mg/100g by Killiani reaction and 191, 114, 112, 99, and 169mg/100g by OPA reaction and 147, 100, 95, 89, and 107mg/100g by enzymatic reaction respectively.
3. The extract of each shellfish was streaked on a preparatorythin-layer chromatografic plate and developed in a solvent system of chloroform and acetone (90:10). Four compounds were visualized under UV light for shijimi and three for other shellfish. Five compounds were stained with Liebermann-Burchard reagent for shijimi, and three for asari and akagai, and two for hamaguri.
4. Analysis of GLC showed that each shell-fish contained C26-sterol, 22-dehydrocholesterol, brassicasterol, 24-methylenecholesterol and C29-sterol besides cholesterol. Kaki was found to contain campesterol and β-sitosterol.
Cholesterol content for all sterols in each shellfish was 70% for shijimi, 56% for akagai, 61% for asari, 55% for hamaguri and 44.5% for kaki, and fairly high concentration of brassicasterol and methylenecholesterol was found in each shellfish.
