兰州鲇肌肉生化成分分析及营养学评价

ANALYSIS OF BIOCHEMICAL COMPOSITION AND EVALUATION OF NUTRITIVE QUALITY IN MUSCLES OF SILURUS LANZHOUENSIS

测定了黄河中上游特有鱼类兰州鲇的肌肉生化成分并对其进行了营养学评价。结果表明,兰州鲇肌肉(鲜样)中粗蛋白质量分数(17.4±0.7)%,粗脂肪(2.22±1.09)%,粗灰分(1.12±0.09)%,水分(80.4±0.8)%。肌肉中含有18种氨基酸,总量为(71.29±3.71)%(质量分数,干样),其中含量最高的为谷氨酸(10.43±0.47)%,含量最低的为胱氨酸(0.663±0.040)%,8种人体必需氨基酸总量为(30.24±2.18)%,占氨基酸总量的42.38%,其构成比例符合FAO/WHO标准。兰州鲇肌肉中限制性氨基酸为缬氨酸、亮氨酸和异亮氨酸,必需氨基酸指数(EAAI)为69.3,4种鲜味氨基酸总质量分数为24.62%(干样)。不饱和脂肪酸占脂肪酸总量的65.21%,并以油酸(C18∶1)和亚油酸(C18∶2)为主。磷含量显著高于其余12种矿物元素(p<0.05),锌在8种微量元素中含量(10.18mg/kg,鲜样)最高,铁(8.31mg/kg,鲜样)次之,硒含量(0.31mg/kg,鲜样)丰富。从营养学角度,兰州鲇是一种营养价值较高的优质鱼类。

Measurements were made on biochemical components in muscles of Silurus lanzhouensis which is an endemic fish living in the middle-up reach of the Yellow River. Samples were collected from Hukou to Sanmenxia section of the Yellow River in China during 2004--2005. Main nutrient contents, amino acids, fatty acids and main mineral element were analyzed by using 6 groups and trace element by 11 groups, which from 42 individuals. Each group was composed of 3 individuals. The results showed that contents of crude protein,crude fat, ash and moisture of fresh muscle were （ 17.4 ±0. 7 ） % , （ 2.22 ± 1.09 ） % , （ 1.12 ±0. 09 ） % and （ 80.4 ±0. 8 ） % respectively. The composition of amino acids of muscle was 18, among which there were 8 essential amino acids for human needs. In dry sample, the total content of amino acids was （71.29 ±3.71 ）% ;the content of essential amino acids was （30.24 ±2. 18）% ;4 kinds of delicious amino acids accounted for 24.62%. Glu was the most abundant and Cys was the shortest in all amino acids of the muscle. The percentage of essential amino acids in total was 42.38%. The essential amino acids index （EAAI） was 69.30 and the constitutional rate of essential amino acids accorded with FAO/WHO standard. According to nutrition evaluation, in the amino acids score （AAS） and chemical score （CS）,the limited amino acids of Silurus lanzhouensis were Val, Leu and Ite. 4 saturated fatty acids and 9 unsaturated fatty acids were found in muscle and the amount of unsaturated fatty acids was 65. 210%. C18： 1 and C18：2 were the main unsaturated fatty acids,which was 41. 531% and 7. 309% respectively. Minerals such as P, Na,K,Ca,Mg,Zn,Fe and Se were rich in these samples. The content of P was significantly higher than other mineral elements （p 〈 0.05 ）. In all elements, Zn was the richest microelement, which was 10. 18 mg/kg （fresh） , Fe and Se were secondary and tertiary mieroelment, respectively,which was 8.31 mg/kg and 0.31 mg/kg. Furthermore, the ratio of Zn and Cu was not rational, so were Zn and Fe. Our study indicated that Silurus lanzhouensis was one of the freshwater fishes with better nutritive value and raising value.