The Effect of Bacterial Fermentation on Protein Solubility in a Sausage Model System

ABSTRACTS The solubilities of myofibrillar and sarcoplasmic proteins were studied in response to bacterial fermentation in a simplified system. As pH decreased from 7.4 to 4.6, the solubility of the myofibrillar fraction decreased 60% and that of sarcoplasmic proteins decreased 40%; solubility of sarcoplasmic proteins previously adjusted to 0.67M NaCl decreased 50%. Sarcoplasmic proteins with and without added NaCl were more susceptible to insolubilization from heat than were the myofibrillar proteins. The myofibrillar preparation showed a marked increase in nonprotein nitrogen during fermentation whereas the sarcoplasmic fraction exhibited only a small incrcase in nonprotein nitrogen.