Potential biomarker discovery for texture and yield quality changes in marinated Nile tilapia (Oreochromis niloticus) meat based on label-free proteomics

Tilapia marinated with 6% ( w/v ) NaCl and 1% ( v/v ) acetic acid for 36 h, which exhibited optimum pH, acidity, water-holding capacity, drip and cooking losses, and the highest sensory acceptance (p < 0.05), was selected for label-free proteomics comparison with non-marinated meat to identify candidate biomarkers related to yield and texture. A total of 50 differentially abundant proteins (DAPs) (23 up-regulated and 27 down-regulated; p < 0.05, |FC| > 1.5 or <0.67) were identified, primarily structural proteins and metabolic enzymes. Gene ontology enrichment indicated protein binding as the predominant molecular function, linked to biological processes including response to abiotic and temperature stimuli, muscle contraction and system process, and protein refolding. Ten significantly enriched pathways (P-value < 0.05, FDR < 0.01, and impact > 0.05) were associated with textural changes, with glycolysis/gluconeogenesis exerting the greatest impact. Several highly interconnected proteins (ACTA1, PYGMA, RPSA, ACTN3, VCL, HSPA8, and RPS7) emerged as promising candidate biomarkers for differentiating fresh and marinated tilapia with superior texture.