CHANGES IN FREE AMINO SCIDS OF YELLOW SEA BREAM BRANCHIOSTEGUS JAPONICUS JAPONICUS DURING DEHYDRATION

옥돔건조중의 유리아미노산의 변화

Yellow sea bream, Branchiostegus japonicus, has been one of the widely consumed food fish in Jeju-Do, Korea. This study was attempted to establish the basic data for evaluating changes of taste compounds of the yellow sea bream during dehydration. The free amino acids were analysed by amino acid autoanalyser. The free amino acid composition of the raw yellow sea bream, abundant amino acids were lysine, alanine, threonine and arginine and then taurine, serine, proline, glycine, glutamic acid, leucine in order. Such amino acids as valine, methionine, tyrosine, isoleucine, phenylalanine were poor in content. The changes of free anino acid composition in the extract of the yellow sea bream during dehydration was not found. In the extract of dried product, lysine, alanine, glutamic acid and arginine were dominant holding $18.4\%,\;14.7\%\;8.0\%\;and\;7.3\%$ and $7.3\%$ of total amino acids respectively. The amount of total free amino acids of the yellow sea bream increased to more than 1.4 times during dehydration process, that of raw sample especially aspartic and glutamic acids increased to more than 2.9 times and 2. 1 times whereas taurine and histidine decreased ranging $40-50\%$ of the original content. It is presumed that the characteristic flavor of dried yellow sea bream was attributed to such amino acids like lysine and alanine known as sweet compounds, glutamic acid as meaty taste and TMAO known as plain sweet taste.

제주도에서 즐겨 먹어온 전통적인 수산식품중의 하나인 옥돔, Eranchiostegus japonicus japonicus, 건조중의 유리아미노산을 분석한 결과 생원료와 건조옥돔에서 17종의 유리아미노산을 분리 고정할 수 있었다. 생원료의 유리아미노산 조성을 보면 함량이 많은 것은 lysine, alanine, threonine, arginine이고 그 다음이 taurine, serine, proline, glycine, glutamic acid, leucine이고 valine, methionine, tyrosine, isoleucine, phenylalanine은 함량이 적었고 특히 aspartic acid와 histidine은 그 함량이 제일 적었다. 옥돔건조중 유리아미노산 조성에는 변화가 없었다. 그리고 건조중 유리아미노산 총량은 생원료에 비하여 $40\%$ 증가하였다. 건조옥돔에는 전체 유리아미노산중 lysine이 $18.4\%$, alanine 이 $14.7\%$, glutamic acid가 $8.8\%$, arginine이 $7.3\%$로서 이들4종 아미노산이 전 유리아미노산의 $48.4\%$를 차지하였다. 또 건조중 특히 많이 증가한 아미노산은 aspartic acid와 glutamic acid로 각각 2.9배, 2.1배 증가하였으나 taurine과 histidine은 $48\%,\;44\%$씩 감소하였다. 건조옥돔의 유리아미노산 중에는 좋은 맞을 가진 glutamic acid, 단맛을 가진 lysine, alanine이 많이 함유되어 있고 또 TMAO도 많이 함유되어 있으므로 이들이 복합적으로 건조옥돔의 독특한 맛에 중요한 구실을 할 것으로 생각되어진다.