Effect of processing methods and starter culture (Staphylococcus xylosus and Pediococcus pentosaceus) on proteolytic changes in Turkish sausages (sucuk) during ripening and storage.

Proteolytic changes in Turkish sausages (sucuk) produced by two methods (heat processing and traditional) were determined during processing and storage for 90 days. The sausages were produced with or without starter culture in both methods. A mixture of Staphylococcus xylosus and Pediococcus pentosaceus was used as starter culture for their acidic and proteolytic characteristics. The major changes in proteolytic characteristics of sucuk took place during the fermentation stage, with an increase in non-protein nitrogen (NPN) and a decrease in protein solubility. Proteolytic activity was observed in both starter-inoculated and non-inoculated (control) sausages during processing. Moreover, a slight increase in proteolytic activity was detected during storage in both starter-inoculated and control traditional sausages, and also in heat-processed sausages due to some heat-resistant proteolytic enzymes. Protein solubility was significantly affected by processing time and heat treatment. Sarcoplasmic and myofibrillar proteins were also affected by starter addition, fermentation, drying and heat processing. During fermentation, starter-inoculated and control sausages showed intense proteolysis in both the traditional and heat processing methods. After heating, intensive degradation of both sarcoplasmic and myofibrillar proteins due to denaturation was observed in heat-processed samples.