刀鲚两种生态类群-＂江刀＂和＂海刀＂鱼肉营养组成的比较及品质的评价

Comparison and evaluation of nutrient composition of two ecological groups of Japanese grenadier anchovy-river-anchovy and sea-anchovy

采用常规方法对刀鲚两种生态类群("江刀"和"海刀")的鱼肉营养成分进行了分析比较并评价了鱼肉品质。结果表明,"江刀"鱼肉粗脂肪含量显著高于"海刀"(P<0.01),是"海刀"的2.03倍,而粗蛋白、水分、灰分含量则低于"海刀"。"江刀"和"海刀"鱼肉的水解氨基酸组成基本一致,均含有18种氨基酸,总量分别占鱼肉鲜样的11.55%和15.37%,其中7种EAA(Leu、Ile、Phe、Try、Thr、Val、Lys)、1种HEAA(Arg)和4种NEAA(Glu、Ser、Tyr、Pro)的含量在"江刀"与"海刀"间存在显著性差异(P<0.05),8种人体必需氨基酸含量分别占鲜样的4.87%和6.4%,与非必需氨基酸的比值分别为85.59%、83.44%,其必需氨基酸构成比例符合FAO/WHO的标准。另外,必需氨基酸指数(EAAI)分别为22.32、41.82,支链氨基酸与芳香族氨基酸的比值(F值)分别为2.43、2.49,4种鲜味氨基酸含量分别占鲜样的4.59%、6.12%;"江刀"鱼肉鲜样中牛磺酸含量(265.43 mg/100 g)显著高于"海刀"(200.93 mg/100 g)。采用甲酯化法衍生化"江刀"、"海刀",再经GC/MS分析鉴定出20种脂肪酸,其中饱和脂肪酸(SFA)9种,单不饱和脂肪酸(MUFA)5种,多不饱和脂肪酸(PUFA)6种。"江刀"多不饱和脂肪酸(9.05%)显著低于"海刀"(13.20%),其中"江刀"EPA与DHA(4.21%、2.26%)显著低于"海刀"(6.71%、2.92%),但绝对含量显著高于"海刀"(P<0.05);ω3PUFA/ω6PUFA值分别为2.67和2.87。全鱼肉中矿物质含量丰富,尤其是Se,Na、Mg、Se的含量在"江刀"和"海刀"之间均存在明显的差异。本研究结果将为刀鲚种质标准的建立和两种生态类群的鉴别提供科学依据。

In this study, to evaluate the fish quality, the nutritional composition of two ecological groups of Japanese grenadier anchovy （river-anchovy and sea anchovy ） were analyzed. The results showed that the crude lipid content of the whole fish in river-anchovy was significantly higher than that of sea anchovy （P 〈 0. 01 ） and was 2.03 times higher. However, the crude protein, moisture and ash content were less than that of sea anchovy; two ecological groups of Japanese grenadier anchovy have almost the same amino acid composition, and both contain 18 amino acids, accounting for 11. 55% and 15. 37 % in wet weight respectively. We also found that the content seven kinds of EAA （Leu, Ile, Phe, Try, Thr, Val, Lys）, the HEAA （Arg） and four kinds of NEAA （Glu, Ser, Tyr, Pro） in the two species have a significant difference （P 〈0.05）, 8 essential amino acid content in the fresh fish is 4.87% and 6. 4% , while the ratio of nonessential amino acids were 85.59% and 83.44%. It is basically in agreement with the standard value issued by FAO （Food and Agriculture Organization） in the United Nations and WHO （World Health Organization）. Moreover, the essential amino acid index （EAAI） was calculated and were 22.32 and 41.82; branched-chain amino acids and aromatic amino acid ratio （ F value） were 2.43 and 2.49. Four kinds of amino acid content in river-anchovy （4.59 % ） was significantly lower than that of sea anchovy（6.12% ） ; The taurine content of river-anchovy was as high as 265.43 mg/100g, which was significantly higher than that of sea anchovy. 20 kinds of fatty acids in river-anchovy were identified by using methyl esterization, which included 9 saturated fatty acids （SFA）, 5 single-unsaturated fatty acids （MUFA） and 6 polyunsaturated fatty acids （PUFA）. The polyunsaturated fatty acids （9. 05 % ） in Coilia nasus was significantly lower than that of sea anchovy （13.20%）. Similarly, this tendency toward decreased EPA and DHA was also observed in river-anchovy （4.21%, 2. 26%） as compared to sea anchovy （6. 71%, 2. 92%）. However, river-anchovy have a pronounced higher level of absolute content than that of sea anchovy（ P 〈0.05 ） ; ω3 PUFA/ω6 PUFA values were 2.67 and 2.87. All the fish are rich in mineral content, especially selenium. The content of Na, Mg, Se in river-anchovy and sea anchovy are significantly different. Overall, the present study will necessitate further research efforts to the establishment of standards and provide identification information for the two kinds of Coilia nasus ecological groups.