Abstract: High-intensity ultrasound (HIU)-aided isoelectric solubilization/precipitation (ISP) was applied to prepare protein isolate (PI) from chicken ribs, and the composition and gel properties of the PI were evaluated. The results showed that myofibrillar proteins were the major components of the PI. Acid treatment induced the degradation of myosin heavy chain in the PI, which could be evidently lessened by HIU. Alkaline treatment did not affect heat-induced gel properties (hardness, cooking loss and centrifugal loss) of the PI as compared to the control group. Gel properties of the PI prepared under acid conditions were significantly (P < 0.05) worse than those under alkaline conditions. HIU significantly increased the hardness and springiness, and reduced the cooking loss and centrifugal loss of heat-induced gels of the PI by acid ISP method (P < 0.05). The whiteness of all PI gels was significantly lower than that of the control gel (P < 0.05). The PI by alkaline ISP method gel had better water-binding capacity than PI by acid ISP method gel. Both PI by alkaline ISP method and control gels showed a uniform and dense microstructure, while the microstructure of PI by acid ISP method gel was coarse and non-uniform. In conclusion, HIU-aided ISP under alkaline condition is effective to extract myofibrillar protein from chicken ribs while maintaining its gelation capacity, which is significant for value-added utilization of chicken ribs.

Key words: chicken ribs; isoelectric solubilization/precipitation; high-intensity ultrasound; protein isolate; gel properties