Changes of the Composition of Nitrogenous Compounds in Globefish Meat Extracts by the Cooking Method

가열조리가 복어 추출물 함질소화합물의 조성에 미치는 영향

Globefish, Fugu xanthopterus, known to have a severe toxin, is one of the favorite food in Korea and Japan when the toxic part is removed. In this paper, the effect of cooking on the composition of nitrogenous components in the extractives from globefish cooked investigated and the changes of the taste compounds originated from the nitrogenous components in the extractives were discussed. When the sample fish was analysed for general composition, drip amount and pH by the different methods of thawing, the method effective method was the running water thawing. Total nitrogen content in raw globefish and the frozen globefish was not different, and the nitrogen content was increased with the heat treatment. It seemed that the nitrogen content was higher in the extract from the boiled globefish than that of the steamed globefish. Taurine, lysine, glycine and alanine were occupied about 70% of the total free amino acids. Total free amino acid content was higher in the extracts from the frozen sample than those from the raw sample. The amount of free amino acids was increased when the globefish soup cooked under the direct-heat cooking than in the microwave oven-heat cooking. Among nucleotides in the extracts from the thawed and cooked fishes, IMP and inosine contents were increased, and the both components were decreased with the heating time and by the heating method. Tne content of total creatinine-nitrogen were 50% of the total nitrogen content of the extracts, but the concentration of glycinebetaine, TMA and TMAO were only a few amounts. It could be concluded that total creatinine components, including free amino acids such as taurine, lysine, glycine and alanine, and IMP might be the important components contributing to the taste of the cooked globefish.