不同年龄段养殖宽体沙鳅肌肉营养成分分析与评价

采用国家标准方法对1、2、3龄宽体沙鳅养殖群体的肌肉营养成分及品质进行了分析比较。结果显示: (1)各年龄组宽体沙鳅肌肉粗蛋白质和粗脂肪含量较高且随着年龄的增长呈增长趋势。其中, 粗蛋白在2龄和3龄组增长不显著(P>0.05), 粗脂肪增长显著(P<0.05)。(2)各年龄组肌肉氨基酸组成相同, 均以鲜味特征氨基酸谷氨酸含量最高, 其次为天门冬氨酸; 第一限制性氨基酸均为缬氨酸; 支链氨基酸与芳香族氨基酸的比值(F值)分别为2.22、2.08和2.12。(3)各年龄组宽体沙鳅脂肪酸在组成和含量上略有差异, 表现为不饱和脂肪酸含量高于饱和脂肪酸含量(P<0.05); 不饱和脂肪酸中单不饱和脂肪酸含量较高(P<0.05); 多不饱和脂肪酸(PUFA)在2龄组最高(P<0.05)且EPA+DHA含量随年龄的增长递增(P<0.05)。综上, 各年龄段宽体沙鳅肌肉营养丰富, 味道鲜美, 以2龄鱼体营养质量最优。

NUTRITIONAL COMPOSITION OF MUSCLE IN CULTURED SINIBOTIA REEVESAE POPULATION AT DIFFERENT AGES

Sinibotia reevesae, an endemic fish, live only in the upper reaches of the Yangtze River. To study nutritional composition in muscle during different growth phases, the main nutrient components in the muscles of age 1, 2 and 3 farmed (fed formulated feed) S. reevesae were analyzed, and the nutritional value and product flavor were evaluated. The general nutrient compositions were determined by routine methods, the amino acid compositions were measured with an amino acid analyzer and the fatty acid compositions by gas chromatography-mass spectrometry (GC-MS). The results showed that the contents of crude protein and crude fat in S. reevesae muscles increased with fish growth. With the increase of age, the moisture content decreased, whereas the contents of crude protein and crude fat increased. The crude protein in muscles of age-group 3 was significantly higher than that of the other two groups (P<0.05), while no significant difference was found in crude protein content between age-group 2 and 3 (P>0.05). The contents of different amino acids in muscles ofS. reevesae among 3 groups were stable. Glutamic acid, aspartic acid and lysine were the most abundant among 16 kinds of amino acids detected in muscles of each group. The essential amino acid index (EAAI) and the ratio of branched chain amino acid to aromatic amino acid (F value) of S. reevesae were very high. According to nutrition evaluation in amino acid score (AAS) and chemical score (CS), the first limiting amino acid for muscles of S. reevesae during different growth phases was valine acid. Totally 7 saturated fatty acids (SFA), 6 mono-unsaturated fatty acids (MUFA), and 7 poly-unsaturated fatty acids (PUFA) were found in dry muscles of S. reevesae from each group. The content of SFA was significantly lower than that of unsaturated fatty acids (UFA) (P<0.05), and the total content of MUFA, especially C_18:1n9c, was significantly higher among UFA. PUFA in age-group 2 was significantly higher than that of the other two groups (P<0.05). The total content of EPA and DHA was lower than other Cobitidae fishes with the tendency to descend with the increasing age. These results indicate thatS. reevesae is a kind of high nutritional value, delicious, and high quality fish, and that S. reevesae in age 2 and 3 age are great for consume because of higher contents of crude protein and crude fat, better amino acid and fatty acid compositions in muscle.