不同规格野生黄鳍金枪鱼肌肉营养分析与评价

Analysis and evaluation of the muscle nutrition of different sizes of wild yellowfin tuna (Thunnus albacares)

中文关键词: 黄鳍金枪鱼  肌肉  规格  营养成分  氨基酸  脂肪酸

英文关键词: Yellowfin tuna (Thunnus albacares)  Muscle  Size  Nutritional components  Amino acids  Fatty acids

中文摘要:

      探究不同规格黄鳍金枪鱼(Thunnus albacares)肌肉营养成分及品质差异，实验以野捕的 3种规格黄鳍金枪鱼J1 (4.2±1.2) kg、J2 (22.5±2.5) kg和J3 (50.8±3.9) kg为研究对象，通过常规生化分析方法对金枪鱼肌肉的常规营养成分、氨基酸、脂肪酸及矿物质元素进行比较分析。结果显示，(1) J1组水分含量显著高于J2、J3组；J2、J3组粗蛋白含量显著高于J1组(P<0.05)；J3组粗脂肪含量显著高于J1、J2组(P<0.05)。(2)检出19种常见氨基酸，氨基酸含量最高的为谷氨酸(3.04~ 3.25 g/100 g)，必需氨基酸中含量最高的为赖氨酸(2.02~2.15 g/100 g)，最低的为色氨酸(0.31~ 0.45 g/100 g)。非必需氨基酸含量J3>J2>J1 (P<0.05)；必需氨基酸、呈味氨基酸含量J1组显著低于J3组(P<0.05)。依据氨基酸评分(AAS)，缬氨酸为第一限制性氨基酸；以化学评分(CS)为评分标准，J1、J2组第一限制性氨基酸为色氨酸，J3组为苯丙氨酸+酪氨酸。(3)各组共检出25种脂肪酸，以多不饱和脂肪酸(PUFA)为主，含量最高的为二十二碳六烯酸(DHA)，占总脂肪酸含量的37.46%~39.18%。DHA含量J3组显著高于J1、J2组；二十碳五烯酸(EPA)含量J2、J3组显著高于J1组；DHA∶EPA比值J1组显著高于J2、J3组(P<0.05)。单不饱和脂肪酸(MUFA)含量J3>J2>J1；PUFA含量J3组显著高于J1、J2组(P<0.05)。PUFA/饱和脂肪酸(SFA)、n-3系多不饱和脂肪酸/n-6系多不饱和脂肪酸(n-3/n-6)比值J2、J3组显著高于J1组(P<0.05)。h/H比值J3组显著高于J1、J2组(P<0.05)。(4) J2、J3组Na、Ca含量显著高于J1组，J1组K含量最高且显著高于J2、J3组(P<0.05)。4种重金属元素均低于食品中建议的最大允许限量，其中Fe含量最大的为J3组，且J3>J2>J1 (P<0.05)；Cu含量最大的为J3组，且显著高于J1组(P<0.05)。综合分析，大规格黄鳍金枪鱼具有更好的营养质量，本研究为居民膳食的选择及黄鳍金枪鱼人工配合饲料的配制提供了科学依据。

英文摘要:

      Yellowfin tuna (Thunnus albacares) is popular with consumers due to its delicious meat and high nutritional value. It is a globally recognized high-end marine economic fish. With the advancement of fishing equipment and the increase in fishing efforts, the amount of tuna resources has decreased significantly. To make up for the insufficient supply of tuna in the market and protect wild populations, it is essential to carry out research on artificial aquaculture technology for tuna and to gradually establish full-cycle cultures of tuna. In order to study the differences in the nutritional components and quality of yellowfin tuna muscles of different sizes, three different-sized yellowfin tuna, J1 (4.2±1.2) kg, J2 (22.5± 2.5) kg, and J3 (50.8±3.9) kg, were used as the research subjects, and conventional biochemical analysis methods were used to compare and analyze the proximate compositions, amino acids, fatty acids, and mineral elements of tuna muscle. The results showed that (1) the moisture level of the J1 group was significantly higher than that of the J2 and J3 groups (P<0.05); the crude protein levels of the J2 and J3 groups were significantly higher than that of the J1 group (P<0.05); and the crude fat level in the J3 group was significantly higher than that in the J1 and J2 groups (P<0.05). (2) A total of 19 common amino acids were detected in yellowfin tuna muscle, including nine essential amino acids (EAA), two semi-essential amino acids, and eight nonessential amino acids. The amino acid with the highest content was glutamic acid (3.04~3.25 g/100 g) of the three tuna sizes; the essential amino acid with the highest content was lysine (2.02~2.15 g/100 g), and the essential amino acid with the lowest content was tryptophan (0.31~0.45 g/100 g). The amino acid content of different-sized yellowfin tuna varied greatly, except for threonine, valine, methionine, isoleucine, tyrosine, and phenylalanine, which were not significantly different among the groups, and the other amino acid contents were mainly J3>J2>J1. The content of nonessential amino acids was J3>J2>J1 (P<0.05). The content of essential amino acids and delicious amino acids in the J1 group was significantly lower than that in the J3 group (P<0.05). The content of semi-essential amino acids in the J1 group was significantly lower than that in the J2 and J3 groups (P<0.05). The ratio of EAA/TAA (total amino acids) in each group was above 40%, and there were no significant differences. According to the Amino acid score (AAS) score, the valine score in each group was the lowest and < 1, which was the first limiting amino acid. According to the chemical score (CS) score, except for lysine and tryptophan of the J3 group, the scores of other amino acids were all less than 1. The first limiting amino acid of groups J1 and J2 was tryptophan, while the first limiting amino acids of the J3 group were phenylalanine + tyrosine. (3) A total of 25 fatty acids were detected in the muscles of yellowfin tuna of three sizes, including 10 saturated fatty acids (SFAs), 5 monounsaturated fatty acids (MUFAs), and 10 polyunsaturated fatty acids (PUFAs). There were nine fatty acids whose content was greater than 1%, and their average content ranged from high to low: C22:6n3 docosahexaenoic acid (DHA), C16:0, C18:0, C18:1n9c, C20:5n3 eicosapentaenoic acid (EPA), C20:4n6 arachidonic acid (ARA), C18:2n6c, C24:1n9, and C16:1n7. Among these nine fatty acids, only C16:0, C24:1n9, and C16:1n7 showed no significant differences (P>0.05). The fatty acids in yellowfin tuna muscle were mainly PUFAs, and the content of DHA accounted for 37.46%~39.18% of the total fatty acid content. The DHA content of the J3 group was significantly higher than that of the J1 and J2 groups (P<0.05). The EPA content of the J2 and J3 groups was significantly higher than that of the J1 group (P<0.05). The DHA:EPA ratio of the J1 group was significantly higher than that of the J2 and J3 groups (P<0.05), and the MUFA content was J3>J2>J1 (P<0.05). The PUFA content of the J3 group was significantly higher than that of the J1 and J2 groups (P<0.05). PUFA/SFA and n-3/n-6 ratios of the J2 and J3 groups were significantly higher than those of the J1 group (P<0.05). The h/H ratio of the J3 group was significantly higher than that of the J1 and J2 groups (P<0.05). (4) Among the four macro elements, the contents of sodium and calcium of the J2 and J3 groups were significantly higher than those of the J1 group (P<0.05), and the potassium content of the J1 group was the highest and was significantly higher than that of the J2 and J3 groups (P<0.05). The contents of four heavy metal elements were all far lower than the maximum allowable limit (FAO and WHO) suggested in food, among which the iron content was the highest in the J3 group, and J3>J2>J1 (P<0.05). The copper content was the highest in the J3 group, and was significantly higher than that in the J1 group (P<0.05). Comprehensive analysis showed that large size yellowfin tuna had better nutritional quality, and the results of this study also provide a scientific basis for the selection of residents' diets and the formulation of artificial nutrition feed for yellowfin tuna.