文蛤与美洲帘蛤的营养组成及风味成分比较分析

Comparison of Nutrient Compositions and Flavor Substances between Hard Clam Meretrix meretrix and Northern Quahog Mercenaria mercenaria

为评价文蛤与美洲帘蛤的营养价值,以同一养殖条件下相同月龄的文蛤和美洲帘蛤为试验材料,采用国标营养测定方法及色谱法等对这2种贝类的常规营养成分、脂肪酸、游离氨基酸、核苷酸、无机离子以及挥发性风味物质进行测定和比较分析。试验结果显示:文蛤的粗脂肪含量显著低于美洲帘蛤(P<0.05);脂肪酸组成中,文蛤中的不饱和脂肪酸的含量较高(45.57%),其中二十碳五烯酸、二十二碳六烯酸含量最高,分别占总脂肪酸的13.29%、11.48%,高于美洲帘蛤中的含量;两者的呈味核苷酸总含量无显著差异(P>0.05),文蛤的3种核苷酸腺苷酸、鸟苷酸、肌苷酸均是主要的呈味物质,而美洲帘蛤中肌苷酸对其蛤肉的直接呈味作用不明显;无机离子均是两者风味的主要贡献者,文蛤中Na^(+)、Fe^(2+)、Zn^(+)、Cl-、PO_(4)^(3-)含量显著高于美洲帘蛤(P<0.05),美洲帘蛤中Ca^(2+)和K^(+)含量显著高于文蛤(P<0.05);文蛤和美洲帘蛤的挥发性成分分别为29种和42种,挥发性风味物质成分中,两者的醇类化合物含量最高,对气味贡献较大,尤其是美洲帘蛤中的1-辛烯-3-醇的含量和气味活度值均很高,这有可能是造成美洲帘蛤土腥味重的原因。试验结果表明,文蛤与美洲帘蛤均具有较高的营养价值,文蛤在鲜味和风味上略优于美洲帘蛤。

To evaluate the nutritional value of hard clam Meretrix meretrix and northern quahog Mercenaria mercenaria,the contents of approximate compositions,fatty acids,free amino acids,nucleotides,inorganic ions and volatile flavor substances were comparatively detected and analyzed in the soft body of the same month old hard clam(shell length 20.66±3.24 mm)and northern quahog(shell length 29.70±2.23 mm)under the same aquaculture environment using the conventional nutritional determination methods and mass spectrometry.Results showed that there was significantly lower content of crude fat in hard clam than that in northern quahog(P<0.05),with the mximal content of PUFA in hard clam(45.57%),especially EPA(13.29%)and DHA(11.48%),higher than those in northern quahog,without significant difference in contents of adenylate(AMP),guanylate(GMP),and inosinate(IMP)between the two clams.The three nucleotides exhibited major taste impacts on the hard clam,while IMP of northern quahog did not make much contribution to its taste flavor.The inorganic ions were all found to be the major flavor contributors in the two clams,with significantly higher contents of Na^(+),Fe^(2+),Zn^(+),Cl-and PO_(4)^(3-)in hard clam than those in northern quahog(P<0.05),and significantly higher contents of Ca^(2+)and K+in northern quahog than those in hard clam(P<0.05).There were 29 kinds of flavor-active compounds detected from hard clam and 42 kinds from northern quahog,with the maximal contents of alcohols in these two clams,indicating that alcohols play important roles in the overall odor.The odorant activity value(OAV)of 1-octen-3-ol in northern quahog was significantly higher than that in hard clam,which smelled“earthly”with excessive content.It was found that hard clam and northern quahog both had high nutritional value,a bit better nutrients and flavor substances in hard clam than northern quahog.