Characteristics Analysis of the Compound Gel of Big-eye Tuna Skin Gelatin and κ-Carrageenan Gel

In this study, the gel strength, rheological properties, gel water holding capacity, TPA texture, FTIR infrared spectroscopy and scanning electron microscopy of the compound gel by mixing the big-eye tuna skin gelatin and κ-carrageenan gel in different ratio were studied. It was found that the gel strength, viscosity, storage modulus and loss modulus of the compound gel increased with the increase of the proportion of κ-carrageenan. The water holding capacity of the compounded gel was 75.9% when the ratio of gelatin/κ-carrageenan was 7:3, which was much lower than 97.1% of the gelatin gel. Continue to increase the proportion of κ-carrageenan, gel water holding capacity and texture characteristics increased significantly. The trend of texture was similar with water holding capacity. The results of FTIR infrared spectroscopy indicated that the interaction between κ-carrageenan and gelatin decreased with the increase of the propotion of κ-carrageenan, which showed that κ-carrageenan was the main body of the compound gel. The results of the scanning electron microscopy showed that the surface of compound gel was wrinkled and gathered, which indicated that different degrees of interaction happened between different concentrations of κ-carrageenan and gelatin through hydrogen bonds. In actual production, the properties of the compound gels can be adjusted by changing the ratio of gelatin/κ-carrageenan to meet the needs of different products.