Effect Of Different Compound Starter On The Quality Of Fermented Beef Jerky

In this experiment,Pediococcus pentosaceus 37x-3 and Lactobacillus plantarum37x-6 were mixed with Staphylococcus xylosus and Staphylococcus to select optimum proportion.The fermented beef jerky was producted with starter culture and divided into four groups:control group,starter culture group,whey group and whey+starter culture group.Physical and chemical index,microbial index and volatile flavor of fermented beef jerky were studied in order to developing excellent compound starter and the industrial production of fermented beef jerky.The results are as follows:Based on the growth curve,salt tolerance and nitrite tolerance of the compound strains,three groups of composite strains with a ratio of 1:1:2:1、2:1:2:1、2:1:2:2 are preliminarily selected.At 24 hours,the number of live bacteria in the 1:1:2:1 group reached is 8.3×10~9CFU/g,significantly higher than 2:1:2:1 group 9.1×10~7CFU/g and2:1:2:2 group 3.7×10~8CFU/g(p<0.05).The optimum ratio of the compound starter is1:1:2:1 group.The pH of the starter culture group decreased to 5.11 after fermentation,and whey starter culture group is 5.10,which is significantly lower than control group(p<0.05).After ripening,the Aw and water content of the starter culture group decreased to 0.729 and17.10%respectively,it is significantly lower than control group.The red value of starter culture group is 12.79,it is significantly higher than control group 11.38(p<0.05).The hardness of whey+starter culture group is 1825.463,it is significantly lower than control group(p<0.05).The nitrite content in the whey+starter culture group is 0.503mg/kg,it is significantly lower than control group 2.548mg/kg(p<0.05).After fermentation,the number of lactic acid bacteria and staphylococcus in the starter group was 7.9×10~9CFU/g and 7.1×10~8CFU/g,respectively,which is significantly higher than control group(P<0.05),and the coliform group in the starter group is 5.6×10~2CFU/g,significantly lower than control group(p<0.05).Escherichia coli is not detected in each group after ripening.The acetic acid content in the fermented whey group is 472.33(10~6/g),which is significantly higher than control group 183.33(10~6/g)(p<0.05).After ripening,there are 33flavor substances in whey starter group,mainly is ovaleraldehyde and3-hydroxy-2-butanone.A total of 27 flavor substances were detected in the starter group,mainly trimethylpyrazine and benzaldehyde.Combined with sensory evaluation,the taste score and total score of whey+starter culture group and starter culture group are higher than other groups.