Monthly changes of glycogen, lipid and free amino acid of oyster

Monthly difference of the chemical composition of oyster cultured along the eastern coast of Shandong Province was analyzed. The components analyzed included glycogen, fatty acid and free amino acid (FAA). The content of glycogen was high in January and March (2.89 and 2.82 g(100g)⁻¹ on average, respectively) and low in October (2.07 g(100g)⁻¹ on avarage). The low content of neutral lipids in October reflected a relatively poor nutritional value of oyster (1.42 g(100 g)⁻¹ on average). The main fatty acids of oyster were palmitic acid (16:0), oleic acid (18:1), eicosapentaenoic acid (EPA, 20: 5_ω-3) and docosahexaenoic acid (DHA, 22:6_ω-3). The major FAAs of oyster were Taurine, Glutamicacid, Glycin, Alanine, Arginine and Proline. Taurine was the most abundant FAA with its content ranging from 603 mg (100g)⁻¹ to 1139 mg(100g)⁻¹. The high contents of glycogen, polyunsaturated fatty acid and FAA showed that oyster cultured along the eastern coast of Shandong Province was nutritionally good in January and March.