盐度对凡纳滨对虾肌肉中游离氨基酸含量的影响

通过逐渐升高盐度的方法,分别测定盐度为0、10、20、30和40时凡纳滨对虾肌肉中游离氨基酸(FAA)的含量,实验周期40 h。结果表明:在盐度0~40时,总游离氨基酸(TOFAA)、必需氨基酸(EAA)、非必需氨基酸(NEAA)和鲜味氨基酸(TAA)的含量都随盐度的增加而明显升高(P0.05);特别是当盐度从20增加到30时,肌肉中TOFAA、EAA、NEAA和TAA含量的增高幅度最明显。在凡纳滨对虾肌肉FAA中,含量最高的是甘氨酸(Gly),其次是脯氨酸(Pro)、精氨酸(Arg)和丙氨酸(Ala)。在盐度为0~40范围内,肌肉中主要的渗透压调节因子是甘氨酸(Gly)、脯氨酸(Pro)、精氨酸(Arg)、丙氨酸(Ala)和牛磺酸(Tau);而天冬氨酸(Asp)、丝氨酸(Ser)、缬氨酸(Val)、甲硫氨酸(Met)、异亮氨酸(Ile)、亮氨酸(Leu)和酪氨酸(Tyr)的含量在各盐度组未呈现显著变化(P0.05)。在淡水养殖凡纳滨对虾出售前的40 h,通过提高水体盐度来提高凡纳滨对虾肉质的鲜味是完全可行的。

Salinity responses of free amino acids in the muscle of Litopenaeus vannamei

The content of free amino acids(FAA) in muscle of Litopenaeus vannamei were measured at salinity 0,10,20,30 and 40,and the experiment lasted for 60 h.Results showed that the content of total free amino acids(TOFAA),essential amino acids(EAA),non-essential amino acids(NEAA),and tasty amino acid(TAA) increased significantly(P<0.05) with increasing salinity from 0 to 40.Especially,The content of TOFAA,EAA,NEAA and TAA increased significantly when the salinity varied from 20 to 30.The highest amount of individual FAA in the muscle of P.vannamei were exhibited by glycine(Gly),followed by proline(Pro),arginine(Arg),and alanine(Ala).The main osmo effectors were Gly,Pro,Arg,Ala,and tauring(Tau) when the salinity varied from 0 to 40.The content of aspirate(Asp),serine(Ser),valine(Val),methionine(Met),isoleucine(Iso),leucine(Leu),and tyrosine(Tyr) were not affected by external salinity change(P>0.05).It is possible to improve the tasty and economical value of P.vannamei by increasing the salinity for the latter period of 40 h before harvest.