Effect of the addition of pronase E on the proteolysis in dry fermented sausages.

The effect of the addition of pronase E at two different concentrations on protein breakdown during the ripening of dry fermented sausage was studied. In all batches, water-soluble, non-protein and 5% phosphotungstic acid soluble nitrogens increased sharply during the first days of ripening, then became stabilized until the end of the process (26th day), and the total volatile nitrogen consistently increased during ripening. The greater the pronase E added the higher were the values reached for all these fractions. The changes in total free amino acids showed a similar pattern to that observed for the phosphotungstic acid soluble nitrogen. Histamine and tyramine progressively increased throughout the ripening. By sensory evaluation, no significant differences between the control batch and the batch with the lowest amount of added pronase E were found, but both batches were significantly different (P < 0·1) from the batch manufactured with the highest concentration of pronase E, which was classed as objectionable by the panellists because of its excessive softness.