PROTEOLYSIS IN DRY FERMENTED SAUSAGES - THE EFFECT OF SELECTED EXOGENOUS PROTEASES

The effect of three commercial proteases (pronase E from Streptomyces griseus, aspartyl proteinase from Aspergillus oryzae and papain) on pr otein breakdown and the sensor) characteristics of dry fermented sausa ges was investigated. Water soluble, non-protein, 5% phosphotungstic a cid soluble, 5% sulphosalicylic acid soluble and total volatile basic nitrogen contents increased during fermentation, stabilizing later unt il the end of ripening (26th day). Nitrogen values were always greater in the aspartyl proteinase added batch in comparison with the other p rotease added batches. Total free amino acid changes showed a similar pattern to those observed for the 5% sulphosalicylic acid soluble nitr ogen. The electrophoretic studies demonstrated that proteolysis of hig h molecular weight myofibrillar and sarcoplasmic proteins was more pro minent in protease added batches. It was especially intensive in papai n one. The dominant amino acids at the end of ripening were similar in all batches. Tyramine and histamine increased throughout ripening. No significant differences in sensory properties were found between cont rol and pronase E and papain added batches, but they were significantl y different (p < 0.01) from the sausages containing aspartyl proteinas e, due to an excessive softening. The effect of exogenous enzyme addit ion on the flavour potentiation of dry fermented sausage is discussed. (C) 1997 Elsevier Science Ltd.