Nano tannin as well as preparation method and application thereof

The invention provides nano tannin as well as a preparation method and application thereof, and relates to the technical field of chemical substance modification. The preparation method of the nano tannin provided by the invention comprises the following step of uniformly mixing and stirring the following components in parts by weight: 1 to 20 parts of tannin, 0.2 to 6.5 parts of surfactant, 0.01 to 0.2 part of metal salt, 0.001 to 0.02 part of alkaline substance and 100 to 500 parts of water, so as to obtain the nano tannin. According to the method, a soft template method is adopted to enable tannin and metal ions to be subjected to a coordination chemical reaction to form a coordination compound, the nanometer tannin is prepared by adopting the preparation method, the specific surface area of the tannin is increased, the probability that the tannin makes contact with microorganisms and is combined with the microorganisms is increased, and therefore the inhibition capacity of the tannin on yeast can be impro