Abstract: This study investigated the correlation between the electrical impedance and quality characteristics of mutton stored under controlled freezing-point condition ((?1.0 ± 0.6) ℃) for 8–216 h after slaughter. The quality characteristics such as color, drip loss rate, shear force value and pH were measured, as well as the electrical impedance properties, including intracellular resistance (Ri), extracellular resistance (Re), cell membrane capacitance (Cm), relaxation factor (α), and Cole- Cole plots. The results showed that as the storage time increased, Ri and Re initially increased and then decreased until reaching a stable level for both the positive and negative groups. Cm and α gradually decreased, and so did the radius of Cole-Cole plots. Overall, the electrical impedance properties of the negative group were lower than those of the positive group at the same times postmortem. The positive group maintained better water-holding capacity, color difference and tenderness but showed a decrease in pH compared with the negative one. During a certain stage of storage, Ri, Re and Cm were significantly correlated with water loss percentage, a* value, shear force and pH for both groups (P < 0.05). Therefore, the electrical impedance properties can be importance indicators to evaluate mutton quality at a certain stage of controlled freezing-point storage.

Key words: mutton, electrical impedance, controlled freezing-point storage, meat quality