金草鱼肌肉品质和营养成分分析及评价

Comparison and analysis of nutritional composition in gold grass carp and grass carp muscle

为了评价金草鱼(Ctenopharyngodon idellus)肌肉品质和营养成分,对同塘养殖的金草鱼和普通草鱼肌肉品质和营养成分进行比较分析及评价。结果显示:金草鱼和草鱼的含肉率分别为70.57%和73.13%,肌肉水分含量分别为78.60%和78.40%,粗蛋白含量分别为19.55%和19.95%,粗灰分含量分别为1.80%和1.45%,粗脂肪含量分别为0.39%和0.50%。金草鱼肌肉的冷冻渗出率和蒸煮失重率低于草鱼,贮存损失为2.64%,显著低于草鱼的4.87%。金草鱼肌肉系水力大于草鱼,保水性更好。金草鱼与草鱼肌肉中氨基酸组成合理,必需氨基酸含量丰富,分别为5.45%和5.35%,必需氨基酸/总氨基酸分别为35.16和35.21,必需氨基酸指数为58.88和56.85;不饱和脂肪酸含量丰富,分别占总脂肪酸的73.44%和70.43%。综合分析表明,金草鱼与草鱼均为高蛋白、低脂肪的食品,具有较高的营养价值。金草鱼肌肉的系水力、必需氨基酸含量和不饱和脂肪酸含量大于草鱼。

Grass carp Ctenopharyngodon idella is one of the commonest farmed fish species in China,and its production reached 5. 67 million tons in 2015. Because of herbivory,easy rearing,fast growing and delicious taste,it has been introduced to 109 counties for aquaculture and biological control. Gold grass carp,a yellow strain of grass carp,had been introduced to China as a farming fish in the 1990 s. Fujian and Guangdong are the key breeding provinces in China. At present,there are a few studies of gold grass carp in the growth and genetics,but no studies on nutrition. To improve the basic data of the quality and nutritional composition of the muscle in this species,the artificial propagation of gold grass carp and grass carp were bred in the same pond and fed artificial feed until reaching commodity specifications after 15 months,when gold grass carp reached 1. 38 kg and grass carp 1. 40 kg. The gold grass carp and grass carp were selected respectively to do comparison analysis and evaluation by biochemical analysis method. The indexes of the flesh rate,pH,mineral elements content and the water binding capacity were determined by conventional methods. The composition and content of the amino acids in muscle was determined by acid-hydrolysis method,and the composition and content of the fatty acids was determined by gas chromatography method. Amino acid score（AAS）,chemical score（CS） and essential amino acid index（EAAI） were used to evaluate amino acids,and the reference patterns used were those established by WHO/FAO（1973） and whole hen＇s egg protein. The results were as follows： 1） The general nutrients： the flesh rate,moisture,crude protein,crude fat,and crude ash content of gold and common grass carp were 70. 57% and 73. 13%,78. 60% and 78. 40%,19. 55% and 19. 95%,0. 39% and 0. 50%,1. 80% and 1. 45%,respectively; 2） The water holding capacity： compared with grass carp,the flesh leaching loss and liquid loss of gold grass carp was lower with2. 64% drip loss（less than grass carp＇s 4. 87%）,which indicated that the water binding capacity of gold grass carp＇s muscle was much higher and gold grass carp possessed a better water retention capacity; 3） The amino acid composition： Both grass carp and gold grass carp had reasonable amino acids composition and rich in essential amino acids. The percentages of essential amino acids in gold grass carp and grass carp were5. 45% and 5. 35%,respectively. The rates of essential amino acids to total were 35. 16% and 35. 21% in gold grass carp and grass carp,with the essential amino acid index（58. 88 and 56. 85,respectively）; 4） The fatty acid composition： the content of unsaturated fatty acids of the two groups was rich with the percentage of73. 44% and 70. 43% in total fatty acids,respectively. All these results show that the difference of the general nutritional composition between gold grass carp and grass carp is not significant,both of which are high protein and low fat food with high nutritional value. And gold grass carp owns higher water binding capacity,essential amino acids and unsaturated fatty acid content than grass carp.