Determination of Free Amino Acid Compositon in Phrynium rheedei by Pre-column Derivatization HPLC and Flavor Quality Evaluation

The method for the determination of free amino acids in Phrynium rheedei was established,and its nutritional value and flavor was evaluated. HPLC with phenylisothiocyanateas derivatization reagent,chromatographic conditions were as follows: Using C₁₈ column(4.6 mm×250 mm,5 μm),with sodium acetate buffer-acetonitrile(93∶7)and acetonitrile-water(4∶1)as mobile phrase in gradient elution,flow rate of 1.0 mL/min,column temperature of 40 ℃,the detection wavelength was set at 254 nm.The results showed that the calibration curves of 18 kinds of amino acids showed good linearity within their test ranges(R²>0.9990),and the average recovery rates of the free amino acids in Phrynium rheedei ranged from 98.3%~105.6%(RSD0.63%~3.11%,n=6). The method was stable,sebsitive,good reproducibility,and could be used to determine the content of free amino acids in Phrynium rheedei. The tested results showed that there were 18 amino acids and 8 essential amino acids in Phrynium rheedei. The total content of essential amino acids was 38.85%,which closed significantly the WHO/FAO model value(40.0%),the components of essential amino acids met the requirements of WHO/FAO amino acid model of adult. The contents of delicious amino acids and sweet amino acids were 10.73 mg/g and 5.20 mg/g,which accounted for 22.58% and 46.59% of the total respectively. The contents of Asp and Thr were more,were 3.75 mg/g and 3.33 mg/g respectively. The RCT values of Asp and Cys were 125.00 and 20.50 respectively,had more the contribution to flavour. In a word,Phrynium rheedei contains variety of amino acid,which is reasonable proportion,the content of its flavor amino acids is rich,it has broad development prospects.