Protein Hydrolytic Activity Against Pork Protein Extracts Of Lactoballus Plantarum And Its Application In The Fermented Sausage

The thesis includes three parts:(1)The hydrolysis of whole cells ,cell extracts(CE) and the combination of both(1:1)from Lactobacillus plantarum6003 against pork sarcoplasmic and myofibrillar protein extracts were studied primarily; (2)The effect of the common curing condition(NaCl, NaNO2, Ascorbic acid and temperature)used during the manufacture of fermented sausage on the Acid production and proteolytic activity of Lp6003 against pork proteins extracts was primarily studied;(3)The changes of physicochemical characteristics and microorganism during the fermentation and ripening of the sausage which inoculated Lp6003, Lp6003with 1% papain and non-inoculated were studied. The innovation was that the proteinase systems and the factor of cell level of Lp6003 was predicted primarily. The results in detail are following :(1)This work focuses on the hydrolysis of whole cells, cell extracts(CE) and the combination of both (1:1) from Lactobacillus plantarum6003 on pork sarcoplasmic and myofibrillar protein extracts. The results showed whole cells of Lp6003 initated the more intense hydrolysis of sarcoplasmic proteins after 96h remarkably than those of myofibrillar proteins, and CE almost did not initated the hydrolysis of pork protein extracts. The hydrolysis of the combination of both was more evident than that of the addition of cell only, which proved that CE intensified the proteolysis of cell on pork protein extracts and increased the livability of cells. The action of whole cells deseased the concentration of almost all armino acid from sarcoplasmic proteins remarkbaly, while increased those from myofibrillar proteins.The action of both enzymatic sources on sarcoplasmic proteins caused maximal increases in Glutamic, Alanine, while the action of those on myofibrillar proteins caused increases in Alanine, Lysine.(2)The effect of the common curing ingredient and temperature used during the manufacture of fermented sausage on the acid production of Lp6003 and proteolytic activity of Lp6003 whole cells against pork proteins extracts was studied. The results showed that Lp6003 exhibited a appropriate quantity of acidification at 25 ,3%NaCl or 150ppmNaNO2 incubating in broth; The quantity of acidification of Lp6003 dropped remarkably when using high concentration of NaCl or NaNO2 in broth. Common temperature duringfermentation did not exert a stimulation against pork protein extracts hydrolysis of Lp6003 whole cells, and temperature was the main factor affected the proteinases activity of Lp6003 whole cells; The addition of ascorbic acid favoured the hydrolysis of Lp6003 whole cells to sarcoplasmic protein extract; the addition of NaCl favoured the hydrolysis of Lp6003 whole cells to myofibrillar proteins extract, while no effect was recorded when the addition of NaNO2 and ascorbic acid on the hydrolytic activity of Lp6003 whole cells against the proteins extracts.(3) The changes of microorganism and physicochemical characteristics during the ripening of the sausage which inoculated Lp6003, Lp6003 with 1% papain and non-inoculated were studied. The results showed that Lactobacillus absolutely preponderant microorganism during the ripening of the sausages inoculated Lp6003;which were responsible for the control of bad microorganisms and characteristic of lactobacillus and the security and preservation of the products; The NPN of sausages inoculated Lp6003 (with papain or without papain) have been more than those of the non-inoculated; The pH, TVB-N and NaNO2 concentration of sausages inoculated Lp6003 have been lower than those of non-inoculated. No obvious difference of the quantities of Lactobacillus counts , bacteria counts , pH, TVB-N and rudimental NaNO2 have been observed between the sausages with papain and without papain , while obvious difference of the Aw has been observed since the 5th day between the two kinds sausages.