Molecular structural changes of Korat chicken meat as affected by packaging conditions during cold storage: Correlation to textural traits and sensory acceptance

This study investigated microstructural and molecular changes in Korat chicken (KC) meat, a Thai hybrid known for its unique meat characteristics, under air packaging (AP), vacuum packaging (VP), and modified atmosphere packaging (MAP: 30% CO₂/70% N₂) and their effects on texture and acceptability during 12 days of cold storage. Changes in water- and salt-soluble proteins, insoluble collagen, as well as carbonyl and free thiol contents indicated that MAP and VP effectively slowed protein denaturation and mitigated oxidation during storage better thab AP (P < 0.05). Scanning electron microscopy (SEM) analysis confirmed less myofibrillar shrinkage and collagen degradation in VP and MAP. Both packaging methods also preserved better texture profiles, including shear force, hardness, and water-holding capacity (WHC), and changes in secondary protein structure, resulting in higher tenderness and juiciness scores throughout storage (P < 0.05). Principal component analysis (PCA) showed that α-helix were associated with Day 0 samples, whereas β-sheet and antiparallel β-sheet were associated with AP and VP/MAP samples, respectively, on Day 12. This suggested that O₂ absence promoted the conversion of α-helix to antiparallel β-sheets, enhancing water retention and meat firmness, particularly during extended storage. Notably, on Day 12, MAP preserved WHC (70.16%) and tenderness score (6.62) better than VP (WHC: 68.02%; tenderness score: 5.91) (P < 0.05). This could be plausibly due to the role of CO₂ in shaping anaerobic bacterial growth and reducing physical stress caused by vacuum condition. Therefore, these findings offer insights into optimizing packaging for better texture preservation in KC meat, particularly under MAP.