Improvement in sensory properties of cooked cured pork loin by injection of pork extract fermented by Staphylococcus xylosus

Staphylococcus xylosus 41 was selected from bacteria isolated from cured meat for use in an experiment to improve the sensory properties of cooked cured pork loin. The selection was based on its growth temperature, salt-tolerance, nitrite tolerance, aerobic and anaerobic growth, and proteolytic activity. A fermented pork extract, which is the supernatant of pork suspension solution fermented for 5 days at 25degreesC after inoculation of S. xylosus 41, had a slightly strong characteristic flavor. Cooked cured pork loin produced by using this fermented pork extract was evaluated to have better flavor and significantly (p < 0.05) better taste than those of cooked cured pork loin containing a nonfermented pork extract. The amounts of protein and total amino acids in the fermented extract were less than those in the nonfermented extract, presumably due to decomposition of the protein in the pork suspension solution and absorption of the decomposed amino acids by S. xylosus 41. Acetic acid was produced in the fermented extract, and it was thought to contribute to the improvement in taste of the cooked cured pork loin. Only three kinds of amino acid, glutamic acid, leucine and proline, remained in the fermented extract, and it was thought that they also contributed to the improvement in taste of the cooked cured pork loin. Peptides with higher and lower molecular weights were produced in the fermented extract than those in the nonfermented extract, suggesting that decomposition of proteins to peptides and amino acids proceeded rapidly. From these results, it was concluded that the sensory properties of cooked cured pork loin can be improved by injecting the pork extract that has been fermented by S. xylosus isolated from cured pork loin.