The effects of pulsed ultrasound (PUS) (power: 240w) with varying time (0, 3, 6, 9, 12 and 15min) on rheological and structural properties of chicken myofibrillar protein (CMP) were examined. PUS treatment significantly caused a decrease in the viscosity coefficients (k) but an increase in the flow index (n) value of CMP solutions within short time (0-6min), while had no significant effect for longer time (9-15min). Besides, at 6min, the solubility and microstructure of CMP samples were optimum. The primary structure of CMP was not altered by PUS treatment. However, Raman spectroscopy revealed a decrease in the α-helix and β-sheets proportion and an increase in the β-turn of CMP following PUS treatment. Random coil reached a maximum at 6min. The changes in tertiary and quaternary structure of CMP by PUS treatment also occurred. As PUS time extended, S₀-ANS for CMP increased measured by ANS fluorescence probe method. However, the normalized intensity of 760cm^-1 increased from 0min to 6min, and then decreased to 15min by Raman test. Moreover, the reactive sulphur (SH) contents and disulfide bonds (S-S) of samples increased while the total SH contents decreased within 0-6min. At 9min and above, the contents of reactive SH groups were almost equal to the contents of total SH groups. Differential scanning calorimetry (DSC) of CMP showed that peak temperature (T_d2) for myosin and peak temperature (T_d3) for actin were both reduced in the first 6min, while T_d3 was not observed from 9min following PUS treatment. Therefore, 6min was the optimum PUS time to obtain better CMP rheological and structural properties.

• Ultrasound could improve the flavor profile of unsmoked bacon. • GC-IMS was a superb technology to analyze volatile flavor compounds. • Six volatiles were closely related to flavor improvement after ultrasound. • Enzymatic oxidation was responsible for flavor improvement after ultrasound.