Preparation of lactic acid bacteria DVS in pickle

Pediococcus pentosaceus PP and L.plantarum P158 were used as starting strains for making pickle.High-density culture of bacteria were achieved through filling materials training and constant pH training, pre-freezing conditions and protection formulations were optimized by using 10% skim milk as suspended substrate, lyoprotectant included trehalose, sugar and sodium glutamate. The results showed that when filling materials training and constant pH training were used at the same time, the maximum number of viable cells of Pediococcus pentosaceus PP and L.plantarum P158 were up to 9.01 × 109 cfu /mL and 2.14 × 1010 cfu /mL, respectively.The optimal vacuum freeze- drying conditions of strains PP, P158 were both frozen in liquid nitrogen for 15 min. The optimal protectants formula of strain PP was trehalose 7%, sugar 7%, sodium glutamate 3%. The optimal protectants formula of strain PI58 was trehalose 7%, sugar 7%, sodium glutamate 5%. Under optimal culture conditions and optimal lyophilization conditions, the freeze- dried survival rate of Pediococcus pentosaceus PP and L.plantarum P158 were 95.8% and 75.6%, respectively.