(大连海洋大学 食品科学与工程学院, 辽宁 大连 116023)
(College of Food Science and Engineering, Dalian Ocean University, Dalian 116023, China)
In order to explore the quality traits of Takifugu rubripes as sushi-grade seafood, microstructure and biochemical and nitrogenous compounds properties of Takifugu rubripes skeletal muscle were investigated. The muscle protein composition, ATP-related compounds and free amino acids were emphatically explored. The results showed that the skeletal muscle of Takifugu rubripes presented high-protein and low-fat characteristics which were similar with white fish species. And the crude protein was accounted for 86.30% of the skeletal muscle dry basis, while the fat was only accounted for 0.66%. Histomorphological observations revealed that the connective tissue in the Takifugu rubripes muscle was abnormally abundant. Further analysis found that the collagen content was accounted for 4.53% of the muscle dry basis. The results of nitrogen components analysis showed that the content of salt-soluble protein was the highest, accounting for 40.76% of total nitrogen components, followed by the water-soluble protein 25.71%, insoluble protein 13.24% and alkali-soluble protein 5.18%. In addition, the non-protein nitrogen compounds were rich in the Takifugu rubripes muscle, accounting for 15.10% of total nitrogen components. SDS-PAGE analysis showed that the water-soluble fraction and salt-soluble fraction had a wide variety of protein components compared to the alkali-soluble fractions. The insoluble component was appeared as collagen map. Collagen from muscle and endothelial tissue were extracted which presented smilar bands, and 3 distinct bands(molecular weight above 110kDa) were consisted of β chain and two α chains, respectively. ATP-related compounds analysis showed that the ATP content in the humane slaughtered Takifugu rubripes skeletal muscle was high up to 4.32μmol/g, and the main degradation product IMP (1.35μmol/g) was obtained. And other further degradation products and content is almost zero. A total of 16 free amino acids were detected in the Takifugu rubeipes muscle. The content of lysine, arginine and threonine were higher, followed by glutamic acid, glycine and alanine, which had flavor function.