CO2 modulates oxidative pathways and protein structural remodeling underlying texture changes in goat meat under high-O2 modified atmosphere packaging

High-oxygen modified atmosphere packaging (High-O 2 MAP) effectively preserves the bright red color of red meat but can accelerate oxidative deterioration. Although CO 2 is incorporated to inhibit microbial growth, its role in modulating oxidative and structural changes that govern texture in goat meat remains unclear. This study investigated the effects of increasing CO 2 concentrations (20–40%) in a 50% O 2 MAP on oxidative stress, protein structural modifications, and texture of goat Semimembranosus ( SM ) muscle during 12 days of storage at 4 °C, with atmospheric air (AP) serving as the control. AP resulted in the highest levels of lipid and protein oxidation, reduced antioxidant capacity, increased shear force, and severe microstructural disruption ( P < 0.05). CO 2 concentration markedly modulated oxidative pathways. Elevated CO 2 (40%) accelerated protein oxidation compared with 20–30% CO 2 , as evidenced by higher carbonyl content, decreased α -helix, increased antiparallel β -sheet formation, and greater firmness on Day 12 ( P < 0.05). This structural compaction was associated with oxidation-induced cross-linking of myofibrillar proteins and reduced water-holding capacity. In contrast, moderate CO 2 levels (20–30%) preserved structural integrity, limited oxidative damage, and maintained tenderness and sensory acceptability. Therefore, the findings indicate that excessive CO 2 promoted oxidation-induced structural changes, thereby compromising texture. An optimized CO 2 range of 20–30% within a 50% O 2 -MAP is recommended to balance oxidative stability and textural quality in goat meat during chilled storage.