Evolution of pH during immersion of meat protein matrices in acidic marinades.

The pH value is a fundamental datum to be monitored during marination. A method is proposed for calculating the evolution of pH of turkey meat cubes during marination in an acetic acid solution. It is based on measurement of the buffering capacity by acidification using a strong acid. A calculation based on the dissociation equilibrium of acetic acid is used to estimate the mean pH reached, factoring in the acid content of the meat. For long marination times, the calculated pH is over-evaluated in relation to the experimental value. This can be explained by the significant loss of buffering substances during immersion. After 6h of immersion, the matrix's proton binding capacity may be reduced to just 20% of the initial value. Hence to improve the prediction of meat cut pH during marination, it is necessary to factor in the outgoing flow of buffering substances.