STABILITY OF STERILE BEEF AND BEEF EXTRACT TO PROTEASE AND LIPASE FROM PSEUDOMONAS-FRAGI

Extracellular protease and lipase from Pseudomonas fragi significantly (P < 0.05) decreased color stability of sterile beef at 4°C and sterile beef extract at 4°C and 21°C. Concentrations of free fatty acids (FFA) in enzyme‐treated sterile beef samples were significantly (P < 0.05) higher than in sterile controls held at 4°C indicating hydrolysis of glycerides by lipase from P. fragi. Concentrations of nonprotein nitrogen (NPN) and free amino acids in sterile beef extract treated with extracellular enzyme and held at 4°C and 21°C were significantly (P < 0.05) higher than in controls indicating proteolysis by protease from P. fragi. This was confirmed by SDS‐polyacrylamide gel electrophoresis of enzyme‐treated beef extract stored at 4°C for 6 days. Sephadex G‐100 gel filtration and poly‐acrylamide disc electrophoresis indicated that the molecular size and electrophoretic mobility of the protease and lipase were similar. Copyright © 1979, Wiley Blackwell. All rights reserved