The relationship between pH of pH-model beef and impedance measured using touch-type electrodes.

Meat pH affects its color, texture, and water-holding capacity; however, a method for nondestructively distinguishing high-pH from normal-pH meat is unknown. We investigated the method of preparing an extensive pH-model of beef immersed in different pH buffers and the relationship between pH of the pH-model beef and impedance, measured using touch-type electrodes. The results showed that a model beef of pH 4.91-6.39 could be obtained when a beef steak (pH 5.68) was immersed in a solution of pH 4.0-7.0. In addition, we found a significant negative correlation between immersion pH and drip loss, and between immersion pH and impedance measured at 50 kHz (P < 0.01). These results provide an estimation equation (y = -16.5x + 195.3) that can be used to nondestructively determine the pH (x) of pH-model beef by measuring its impedance (y) using touch-type electrodes at 50 kHz (P < 0.01). Hence, the study shows the possibility of nondestructively estimating the pH of pH model beef by measuring impedance using touch-type electrodes.