The invention provides a composite protective agent for increasing the freeze-
drying survival rate of
lactobacillus plantarum and a preparation method thereof. The protective agent is prepared from soybean
polysaccharide,
galactose, fructo-
oligosaccharide,
trehalose,
skimmed milk,
proline and
distilled water. The preparation method includes the steps that the
distilled water is divided into three parts, and soybean
polysaccharide,
galactose, fructo-
oligosaccharide and
trehalose are added to one part for
dissolution and sterilization; the
skimmed milk is added to another part of the
distilled water for
dissolution, and a
skimmed milk solution is obtained and sterilized;
proline is dissolved in the remaining distilled water, and membrane
filtration sterilization is conducted; the three prepared solutions are evenly mixed under the sterile condition, and then the composite freeze-
drying protective agent is obtained. According to the freeze-
drying protective agent for
lactobacillus plantarum, a freeze-drying protective additive is added in the
fungus powder preparation process, the anti-freezing capacity of fungi can be improved, and therefore the freeze-drying
survival rate of the
fungus powder is increased, the storage period is long, and the
survival rate is not likely to be reduced. The freeze-drying survival rate of the prepared
fungus powder of
lactobacillus plantarum ranges from 82.73% to 93.26%, and the
viable count of the fungus powder ranges from 1.14*10<11> cfu / g to 1.98*10<11> cfu / g.