[Dynamics of ammonia and pH in meat stored under various conditions].

The changes in ammonia content and pH values in beef and pork stored at different temperatures were studied in relation with sensory changes. Samples were taken from the stored meat at a temperature of +3 degrees C in the 0th, 12th, 36th, 60th, 84th, 108th and 132nd hour and at a temperature of +10 degrees C in the 0th, 6th, 24th, 36th, 54th, 72nd and 84th hour. The quantity of ammonia in the samples was determined by means of an ion-selective electrode. The pH value was determined potentiometrically. The kinds of meat (pork, beef) differed in the development of ammonia content. Ammonia content was found to be directly dependent on storage temperature. A similar relation was observed in the development of pH values. The sensory changes of stored meat were parallel to the changes in ammonia levels and pH values. The results can be used for an evaluation of the degree of biochemical changes in the meat and of the fitness of the raw material to the production of tins for long storage. Advantageous points are seen in the rapid and objective determination of ammonia content by the ion-selective electrode and the determination of the pH value by means of the combined glass electrode with the aid of the same apparatus.