Flavor Compounds of Dried Shellfishes 2. Changes of Reducing Sugars, Organic Acids and Fatty Acids Composition in Shellfishes during Drying Process

패류 건제품의 향기성분에 관한 연구 2. 건조가공에 따른 패류의 환원당, 유기산 및 지방산 조성의 변화

The levels of reducing sugars, organic acids and fatty acids, known as precursors of major flavors induced from dried sellfish, were analyzed to investigate their behaviors during drying process. Free reducing sugar contents were markedly decreased in all samples by boiling, Its content in Blue mussel and Short-necked calm samples significantly decreased after drying process. Among the eight different organic acids from blue mussel, Short-necked calm and Pacific oyster samples, succinic acid in blue mussel and short-necked calm samples was measured with $74.9\%\;and\;67.4\%$, respectively. In the sample of Pacific oyster, succinic acid content was found to be $38.4\%$, but pyroglutamic acid content was the highest level with $41.6\%$. Contents of organic acids with exception succinic acid were significantly reduced in all three samples of sun-dried or hot-air dried. The content of succinic acid in the samples of sun-dried and hot-air dried pacific oyster reduced to $53.0\%\;and\;44.2\%$, respectively, but relatively small decrease $(29.0\%\;and\;10.0\%)$ was observed in sun-dried and hot-air dried short-necked calm samples, respectively. Content of polar lipid with the major fatty acids profile of C16:0, C16:1, C20:5 and C22:6 was consisted of $59.1\%,\;66.7\%\;and\;42.4\%$, respectively, in blue mussel, short-necked calm and pacific oyster samples and the content of polyene fatty acids was appeared to be $40.5\%,\;48.6\%\;and\;48.9\%$, respectively. Relatively high peroxide value in all boiled-dried products samples was found to be $41.64\~86.80\;meq/kg$ sample. Carbonyl value in boiled-dried products samples was found to be $15.55\~27.99\;meq/kg$, but its value in broiled products samples was significantly high level of $127.6\~136.5\;meq/kg$.

패류 건제품중에 생성되는 향기성분의 주요한 전구체로 알려져 있는 환원당, 유기산 및 지방산의 거동을 살펴보기 위하여 홍합, 바지락 및 굴의 건제품 가공중의 성분조성과 함량의 변화를 조사하였다. 유리환원당의 함량은 자숙후에 큰 감소를 보였으며 홍합과 바지락의 경우에는 건조후에도 크게 감소하였다. 홍합, 바지락 및 굴 에서는 각각 8종의 유기산이 분석되었는데 함량이 높은 유기산은 succinic acid로써 총유기산량의 $74.9\%,\;67.4\%,\;38.4\%$를 차지하였고 특히 굴에서는 pyroglutamic acid의 함량이 $41.6\%$로써 가장높았다. 천일건조 및 열풍건조 후에는 succinic acid 이외의 다른 유기산들의 함량은 급격히 감소하였는데, 굴의 건제품에서는 $53.0\%$와 $44.2\%$의 큰 감소를 보인 반면 바지락의 건제품에서는 $29.0\%$와 $10.0\%$로써 비교적 감소량이 적었다. 지질 성분의 분석결과에서는 극성지질의 함량이 총지질함량의 $59.1\%,\;66.7\%,\;42.4\%$의 높은 값을 보였으며 주요 구성지방산은 C16 : 0, C16 : 1, C20 : 5, C22 : 6등이었고 폴리엔산이 각각 $40.51\%,\;48.6\%,\;48.77\%$의 높은 조성비를 나타내었다. 각 시료의 자건제품의 과산화물가는 $41.64\~86.80\;meq/kg$으로써 비교적 높았고 카아보닐가는 $15.55\~27.99\;meq/kg$으로써 났았으나 배건제품중의 카아보닐가는 $127.6\~136.5\;meq/kg$의 높은 값을 나타내었다.