Screening Of Optimal LAB Strains From Sichuan Pickle Vegetables And The Research On Fermentation Condition

Compared with traditional spontaneous fermentation, inoculating pure LAB topickle fermentation is an innovation, and also a symbol of fermentation technology'smodernization. This research was based on the 115 strains LAB(including 93bacillus, 22 coccus)separated from Sichuan pickle vegetables. By first screening,further screening,combined fermentation experiments, the optimal strains,combination of strains and the optimal fermentation conditions were determined. Theoptimal culture medium which are suitable for radish pickle were determined byorthogonal experiments.The main results are the following:1. Four strains of LAB(J-5,29-13,10-8,W-1)were singled out from 115 strains byfirst screening,further screening,growing condition experiments and inheritancestability experiments.2. According to the screen criterion: acid production and the quality of sense, theoptimal combination of strains were L_cf,L_p,L_c, and the optimal ratio was 1:2:1.And using this combination as start culture in pickle fermentation suggested that these3 strains had fast growth rate, good acid-producing ability, good taste,and pH alsolowered down quickly.3.According to this study, the optimal parameter of fermentation was:6%NaCl, temperature 25℃, start culture 3%. Lactic acid content 1.45mg/ml, pH3.5～3.35。4. Using the combination of L_cf:L_p:L_c=1:2:1, at the optimal fermentationcondition, taking food security for consideration, the control's nitrite peak value was 4times as the experimental group.5. Screened out the optimal culture media by quadratic orthogonal experiments forradish pickle fermentation.