Improvement of Flavor of Cultured Oyster

牡蛎是日本和许多其他国家的流行海鲜之一。然而，在日本，欧洲扁牡蛎的生产和消费非常有限。为了提高养殖牡蛎的消费量，本研究通过投喂浮游植物或配合饲料来改善其风味.以纤细角毛藻（C.g组）和新月菱形藻（Nitzschia closterium N. c组）、球等鞭金藻（I.g组）和配合饲料（RL组）饲养4组欧洲扁牡蛎30 d。对照组置于海中.在可食用部分的感官测试中，许多专家回答I.g组在甜度、鲜味和涩味方面优于对照组，表明前者比后者更容易接受。C.g、N. c和R1组在质构、气味和咸度方面均不如对照组。3. 4个试验组的糖原含量均显著低于对照组。ig组富含牛磺酸、甘氨酸和谷氨酸。C.g组和N. c组的丙氨酸和甘氨酸含量明显不足.饱和、单不饱和和多不饱和脂肪酸（PUFA）分别占总脂肪酸的32- 34%、15- 21%和47-52%。R1组PUFA含量最低，n-3脂肪酸含量较低，n-6脂肪酸含量较高.用活塞测量的消化器官韧性，N. c组为42 g/mm^2，其他组为27-29 g/mm^2。5组消化器官蛋白质组成中，水溶性、盐溶性、碱溶性和不溶性组分分别为35- 53%、21- 33%、18-26%和5- 6%。质构与蛋白质组成无相关性。

Oyster is one of Popular seafoods in Japan as well as in many other countries. However, the Production and consumption of the European Flat oyster, Ostrea edulis, are very Limited in Japan. For the purpose of increasing the consumption of the cultured oystes, the present research aimed at the improvement of its Flavor by feeding phytoplankton or formula food.1. Four groups of European flat oyster were reared on each of two species of diatom, Chaetoceros gracilis (C.g group) and Nitzschia closterium N.c group), a haptophyte, Isochrysis galbana (I.g group) and a formula feed (RL group) for 30 days in tanks. The control group was kept in the sea.2. In the sensory tests of edible parts, many panelists answered that the I.g group was better than the control group in sweetness, umami and astrigency, indicating that the former was more acceptable than the latter. The C.g, N.c and Rl groups were judged to be inferior to the control group in texture, odor and saltiness.3.The contents of glycogen in the 4 test groups were considerably lower than that of the control group. I.g group was rich in taurine, glycine and glutamic acid. Alanine and glycine were markedly poor in the'C.g and N.c groups.4. The levels of saturated, monounsaturated and polyunsaturated (PUFA) fatty acids were 32-34%, 15-21%, 47-52% of total fatty acids, respectively, in the 5 groups. The percentage of PUFA was the lowest in the Rl group, which showed also lower level of n-3 series fatty acids but higher n-6 ones than the other groups.5. The toughness of digestive organs as measured with a plunger was 42 g/mm^2 for the N.c group and 27-29 g/mm^2 for the other groups. As for the protein composition of digestive organs of the 5 groups, the water-soluble, salt-soluble, alkali-soluble and insoluble fractions were 35-53%, 21-33%, 18-26% and 5-6%, respectively. No correlation was observed between the texture and protein composition.