The objective of this study was to investigate the optimal conditions for the microwave combined with steam pretreatment of yellow-feathered broiler carcasses using response surface methodology (RSM). Microwave heating time, steam holding time and number of microwave combined with steam treatment cycles were considered as the independent variables, while the shear force and cooking loss of chicken breast meat were considered as response variables. The optimal processing parameters were as follows: microwave heating time of 30 s, steam holding time of 60 s, and 7 cycles of treatments. Under these conditions, the shear force of chicken breast was 18.31 N, and the cooking loss was 13.10%, both of which were close to the predicted values.

The effect of mixed food gums combined with ultrasonic treatment on physicochemical properties, rheological properties and in vitro digestibility of chicken blood tofu gels was studied. Guar gum mixed with Arabic gum (3:7, m/m) and guar gum mixed with konjac gum (5:5, m/m) were evaluated. The quality of chicken blood tofu was evaluated in terms of its yield, particle size, zeta potential, protein secondary structure, rheology and in vitro digestibility. The results showed that the yield of chicken blood tofu was increased by 15.91% after the addition of guar gum mixed with konjac gum combined with ultrasonic treatment. Additionally, the absolute value of zeta potential was significantly increased (P < 0.05). Fourier transform infrared (FTIR) spectroscopic analysis and microstructure observation indicated that mixed food gums combined with ultrasonic treatment enhanced protein-protein interactions in chicken blood tofu, resulting in the formation of a more stable gel network. The storage modulus G’ and loss modulus G” were increased significantly, but there was no significant difference in phase angle. Additionally, in vitro digestibility of chicken blood tofu was increased to 82.93%. The two treatments had similar effects on the yield, particle size, zeta potential, protein secondary structure, rheology and in vitro digestibility of chicken blood tofu. But guar gum mixed with Arabic gum was generally more effective than guar gum mixed with konjac gum. These results suggested that mixed food gums combined with ultrasonic treatment not only improved the quality of chicken blood tofu gels, but also increased the in vitro digestibility, which can provide a theoretical basis for broiler breeding, slaughtering and processing enterprises to increase the added value of their products.