Abstract: This study systematically investigated the effect of ultrasound-assisted papain treatment on the quality attributes and in vitro digestive behavior of camel meat. Furthermore, proteomic analysis was employed to elucidate the underlying molecular mechanisms governing the quality changes of camel meat. Results indicated that the combined treatment significantly reduced the shear force, hardness, chewiness, and cohesiveness, while significantly increasing the springiness (P < 0.05). Proteomic profiling identified 5 048 proteins and 23 609 peptides, revealing that the combined treatment activated the calcium signaling and apoptosis pathways, downregulated the expression of structural proteins, and enriched digestive system-related pathways, thereby disrupting myofibrils, inhibiting stress repair, and ultimately enhancing both meat tenderness and digestibility through a multi-pathway synergistic mechanism. Correlation analysis between differential proteins and textural properties further verified this mechanism. After in vitro simulated digestion, the combined treatment markedly improved protein digestibility: the pepsin hydrolysis rate, (81.94 ± 1.27)%, and total protein hydrolysis rate, (90.34 ± 1.72)%, increased by 17.57% and 18.06%, respectively, relative to the control group. We observed an elevation in total carbonyl content and a corresponding decrease in total sulfhydryl content, suggesting that moderate oxidation also contributed to improved digestibility. Moreover, the treatment induced significant alterations in protein conformation, as evidenced by decreased intrinsic fluorescence intensity. Electrophoresis results revealed that the combined treatment reduced the density of protein bands in the range of 35–100 kDa compared with the control group, consistent with improved tenderness. Overall, these findings lay a theoretical and technical foundation for the precise regulation of camel meat quality.

Key words: camel meat; ultrasound; papain; tenderization; proteomics; in vitro digestion