Abstract:

The proximate composition and amino acid and fatty acid profiles of muscle in cultured southern flounder,
Paralichthys lethostigma, were analyzed to evaluate its nutritional quality. Southern flounder muscle contained 17.74% crude
protein and 3.02% crude lipid. In addition, Nineteen amino acids were detected, including a large amount of glutamic acid
(120.4 nmg/g crude protein), aspartic acid (75.4 mg/g crude protein), glycine (73.6 mg/g crude protein), leucine (72.3 mg/g
crude protein), lysine (67.8 mg/g crude protein) and arginine (63.4 mg/g crude protein). According to the reference amino acid
pattern recommended by FAO/WHO/UNU (1985) for pre-school children (2 to 5 years old), the scores for all the essential
amino acids were over 100 indicating the muscle of southern flounder to contain high-quality protein with a good amino acid
balance. Total saturated fatty acid, monounsaturated fatty acid and polyunsaturated fatty acid (PUFA) contents in the muscle of
southern flounder were 32.23%, 30.79% and 27.01%, respectively. In n-3 PUFAs, 7.38% eicosapentaenoic acid (EPA, C20:5n-3)
and 12.07% docosahexaenoic acid (DHA, C22:6n-3) were detected, while 4.49% arachidonic acid (AA, C20:4n-6) was detected in n-6
PUFAs. The ratio of ΣPUFA n-6/ΣPUFA n-3 was 0.35, which was significantly lower than the maximum safety value of 4.0
recommended by the UK Department of Health.

Key words: southern flounder Paralichthys lethostigma, proximate composition, fatty acid, amino acid, nutritional assessment