Abstract: This study systematically evaluated the effects of embrittling duration on the quality of tilapia muscle through sensory evaluation, physicochemical analysis, microstructural observation, and myofibrillar protein (MP) structure analysis. The results demonstrated that prolonged embrittling time significantly enhanced muscle hardness, springiness, adhesiveness, and chewiness (P<0.05). Water-holding capacity improved by 6.47% (embrittlement for 90 days), while water distribution analysis revealed decreased free water content and increased bound water content (P<0.05). Microstructural observations indicated that extended embrittling time led to tighter myofibrillar connections and significantly enhanced connective tissue and collagen fibers (P<0.05). In the MP structure, total sulfhydryl content significantly decreased, hydrophobicity increased, α-helix relative content reduced, and β-sheet relative content elevated (P<0.05). Additionally, fluorescence intensity declined, accompanied by a blue shift in the emission wavelength. SDS-PAGE analysis showed that embrittling treatment weakened the expression of MHC, AC, and TM bands and formed high-molecular-weight aggregates. Correlation analysis revealed that the proportion of bound water in muscle, connective tissue proliferation, protein hydrophobic interactions, and intermolecular forces were positively correlated with muscle quality attributes, including hardness, springiness, adhesiveness, and chewiness. Overall, tilapia muscle embrittled for 90 days exhibited optimal sensory attributes, texture, and water distribution, suggesting that 90 days was the recommended duration for embrittling in production.