Composite protective agent for freeze-drying lactobacillus bulgaricus

The invention belongs to the technical field of lactobacillus bulgaricus preservation, and discloses a composite protective agent for freeze-drying lactobacillus bulgaricus, which comprises the following components in percentage by mass: 1-5% of Arabic gum, 0.5-2% of stachyose, 1-5% of cysteine hydrochloride, 2-10% of inulin, 0.2-1% of serum protein and the balance of water. The prepared composite protective agent for freeze-drying adopts multiple active components, does not contain any chemical synthetic substance, and is high in safety. The prepared composite protective agent for freeze-drying is added in the process of preparing lactobacillus bulgaricus powder, so that the anti-freezing capacity of thalli can be improved, the physical and chemical environments during freeze-drying of a biological sample are changed, the damage to the thalli in the freeze-drying or rehydration process is reduced, the survival rate and stability of the lactobacillus bulgaricus thalli are improved, and the survival rate of th