Application And Formulation Optimization Of Three Kinds Of Lactic Acid Bacteria Starters For Fermented Sausage

Fermented sausage is a kind of traditional fermented meat products which has twenty centuries’history. Fermented sausages were produced by people because of its good storage capability at first. With the development of processing technology, fermented sausage had became one of the most characteristic fermented meat products. A very rapid growth has been approached in research work of fermented sausage in recent few decades because of its unique flavor and luxuriant nutrition. The research work of fermented sausage in China hadn’t been brought on the stage sice twenty years ago. Microbial resources in China is so rich that it provides potential for related research work. Lactic acid bacteria (LAB) is the most important microorganism in fermented sausage. LAB in dry fermented meat products, are responsible for a rapid fermentation of carbohydrates added to the mixture, leading to a decrease in the pH. This paper consists of three parts to research potential of senveral strains of LAB as starter cultures.Part I used six strains of LAB which were collected from different areas of China as candidates of starters:L.plantarum NM194-4, L.plantarum NM177-2, L.curvatus GX24-2, L.sakei G13, L.curvatus R7, P.pentosaceus23206. Compatibility, salt and nitrite tolerance ability of six strains were tested in this part. Compatibility test between six strains indicated that there was antibiosis restraining effect between P.pentosaceus23206, L.plantarum NM194-4and L.curvatus R7. Since P.pentosaceus has unique effect on aroma of fermented sausage, L.plantarum NM194-4and L.curvatus R7were passed out in the test. Salt and nitrite tolerance ability test indicated that L.sakei G13was the weakest in nitrite endurance. Among all six strains, L.plantarum NM177-2, L.curvatus GX24-2and P.pentosaceus23206gave the best salt and nitrite tolerance. These three strains would be used as mixed starters in part Ⅱ and part Ⅲ. Also the salt and nitrite contents would be2.3%and0.01%. PartⅡ used L.plantarum NM177-2, L.curvatus GX24-2and P.pentosaceus23206as mixed starters to produce fermented sausages in different fermentation and ripening conditions, then measure pH value, water activity, nitrite determination and peroxide value of the sausages. The resaults indicated that under any fermentation conditions, sausages inoculated L.plantarum NM177-2showed the fastest decrease on pH value. It showed L.plantarum NM177-2provided most acid during fermentation. Water activity values of all the sausages decreased as inoculum concentrations and fermentation temperature increased and all water activity values were under0.9. Among all the strains, sausages inoculated L.plantarum NM177-2had the lowest water activity values. All the sausages nitrite residue were under the GB standard. Fermentation temperature influenced peroxide value most among all the factors. Sausages inoculated L.plantarum NM177-2had the higher peroxide values than all the other sausages.Part Ⅲ used orthogonal test to determine the optimal starters by mixed strains. The best inoculum concentration of L.plantarum NM177-2was107cfu/g. The best inoculum proportion of L.curvatus GX24-2and P.pentosaceus23206was1:3. The best fermentation temprature was25℃. The best fermentation time is40hours. The fermented sausage which was produced under this circumstance had preferable quality and edible safety. SPME-GC-MS was used to analyze the volume of volatile aroma components in fermented sausage and53volatile aroma compounds were detected. It proved that the fermented sausage produced by optima starters had a good sense of flavor.