Analysis and evaluation of the nutritional components of Siganus guttatus muscle.

Biochemical components and amino acids composition in the muscle of Siganus guttatus were tested and analyzed with routine methods.Samples of 10 wild individuals,with(20.04 ± 0.53) cm body length and(305.86 ± 34.00) g body weight,were collected from the South China Sea,near Sanya City of Hainan Province in September of 2007.The results showed that contents of moisture,crude ash,crude protein and crude fat of fresh muscles were 74.27 %,1.60 %,21.20 % and 2.79 %,respectively.The composition of amino acids of muscle was 18 common amino acids,including Tau,and 8 essential amino acids for human needs(no analysis was made for Cys).In dry sample the total content of amino acids was 74.57%;the content of essential amino acids was 31.72%;the percentage of essential amino acids in total amino acids was 42.54%.It was apparent that the content of the different amino acids was stable and the constitutional rate of the essential amino acids accorded with the FAO/WHO Standard,fundamentally.According to nutrition evaluation in amino acids score(SAA) and chemical score(SC),the first limited amino acid was Trp,and the second limited amino acids was Phe +Tyr;the essential amino acids index(IEAA) was 69.77;in dry sample the content of four kinds delicious amino acids was 25.41%,and the percentage of delicious amino acids in total amino acids were 34.01%.We calculated the A/E ratios of 10 essential amino acids for S.guttatus.Based on the descent order of A/E ratios,the first three essential amino acids were Glu,Leu and Arg.The value of A/E ratio for Trp was the smallest in 10 essential amino acids.This descent order was also found in chum salmon.A/E ratios of S.guttatus provided basic materials for research of essential amino acids requirement and artificial food development.