美洲黑石斑鱼含肉率及肌肉营养成分分析

Analysis of flesh content and nutrient components in the muscle of Centropristis striata

利用常规肌肉营养测试方法,测定分析了美洲黑石斑鱼的含肉率及肌肉营养成分。测定结果显示,美洲黑石斑鱼含肉率平均值为(73.71±1.93)%,肌肉(鲜样)中粗蛋白、粗脂肪、水分和粗灰分含量分别为(19.09±1.34)%,(6.14±1.76)%,(71.86±1.58)%和(1.32±0.17)%;美洲黑石斑鱼肌肉中被测出的常见氨基酸(色氨酸未测定)有17种,其中包括7种必需氨基酸、2种半必需氨基酸和8种非必需氨基酸,其氨基酸含量占鲜体质量的百分比分别为(8.27±0.21)%,(1.84±0.08)%和(10.15±0.31)%,17种氨基酸总含量为(20.26±1.13)%(鲜样)。谷氨酸(Glu)含量占鲜体质量的百分比最高,为(3.27±0.16)%,其次是天冬氨酸(Asp)和赖氨酸(Lys),胱氨酸(Cys)含量占鲜体质量的百分比为最低,仅为(0.27±0.01)%。4种鲜味氨基酸含量占干样的(29.32±0.14)%。鲜样的美洲黑石斑鱼必需氨基酸总量占氨基酸总量的比值为40.82%,干样的为40.81%;鲜样的必需氨基酸总量与非必需氨基酸总量的比值为81.48%,干样的为81.43%,其构成符合FAO/WHO的标准。同时计算出的美洲黑石斑鱼肌肉蛋白质氨基酸评分(AAS)均大于1,化学评分(CS)均大于0.7,必需氨基酸指数(EAAI)达到91.18,高于多数海产经济鱼类,说明它能为人体提供大量必需氨基酸,且其组成接近人体的氨基酸需要量模式。美洲黑石斑鱼肌肉中主要含有16种脂肪酸,其中饱和脂肪酸(SFA)7种,含量占肌肉脂肪酸总量的(38.66±1.22)%;不饱和脂肪酸(UFA)9种,含量占肌肉脂肪酸总量的(61.36±0.98)%,其中单不饱和脂肪酸(MUFA)5种,多不饱和脂肪酸(PUFA)4种。多不饱和脂肪酸中的人和动物生长发育必需的脂肪酸EPA和DHA含量,分别占总脂肪酸的(9.02±0.59)%和(11.73±0.43)%。-ω3族与-ω6族PUFA总量的比值为5.30。分析表明,美洲黑石斑鱼肌肉含肉率高,含有较多的粗蛋白和粗脂肪,氨基酸总量及鲜味氨基酸含量均较高,是一种优质蛋白源;美洲黑石斑鱼肌肉富含PUFA,尤其是EPA和DHA含量丰富,并且∑n3/∑n6值较高,因而具有较高的食用营养价值和保健功效,是一种具有广阔市场前景的优良养殖品种。

Centropristis striata,an economically important marine fish originated in the coastal waters of the Atlantic Ocean along the eastern shore of the US and Mexico,has been introduced into China since 2003.In order to evaluate the nutrition value of the fish and to provide basis for defining and calculating the nutrition requirement,the flesh content and nutrient components in the muscle of Centropristis striata are investigated with routine flesh nutrients testing method in this paper.The results show that the rate of flesh content of C.striata is（73.71±1.93）%.Its crude protein,crude fat,moisture,and crude ash in fresh muscle are（19.09±1.34）%,（6.14±1.76）%,（71.86±1.58）%,（1.32±0.17）%,respectively.Seventeen common amino acids excluding Try（which was not determined） are found with TAA of（20.26±1.13）%,including seven essential amino acids（EAA）,two half-essential amino acids（HEAA） and eight nonessential amino acids（NEAA）.The amount of EAA,HEAA and NEAA are（8.27±0.21）%,（1.84±0.08）%,（10.15±0.31）%,respectively.The four delicious amino acids（DAA） make up（29.32±0.14）% of the total in dry sample,in which Glu has the highest content of（3.7±0.16）%,followed by Asp and Lys,and Cys the lowest.The essential amino acids index（EAAI） is 91.18,which is much higher than those of most fish species.The ratio of total essential amino acids to total amino acids（TEAA/TAA） is 40.82%,and the ratio of total essential amino acids to total nonessential amino acids（TEAA/TNEAA） is 81.48%.It is clear that the content of the different amino acids is stable and the constitutional rate of the essential amino acids meets the Standard of the Food and Agriculture Organization of the United Nations/World Health Organization（FAO/WHO）.According to amino acids score（AAS） the first limited amino acid is Val and the second limited amino acid is Met＋Cys.But according to chemical score（CS）,the first limited amino acid is Ile and the second limited amino acid is Val,respectively.There are 16 main fatty acids in the muscle of Centropristis striata including 7 saturated fatty acids accounting for（8.66±1.22）% of the total and 9 unsaturated fatty acids accounting for（61.36±0.98）%,in which 5 are mono-unsaturated fatty acids（PUFA） accounting for（24.46±1.22）% of the total fatty acids and 4 poly unsaturated fatty acids.In poly unsaturated fatty acids,EPA and DHA which account for（9.02±0.59）% and（11.73±0.43）%,respectively are thought to be essential for the growth of human and animals.The ratio of total ω-3 PUFA to ω-6 PUFA（∑n3/∑n6） is 5.30.In conclusion,this study shows that C.striata is a nutritive and delicious edible fish with high content of flesh,in which the contents of crude protein and crude fat,as well as total amino acid and delicious fatty acids are relatively high.The composition model of essential amino acid is in keeping with the requirements of human body.It is a good source of protein of high quality and could be a potential aquaculture species.