Method for reducing content of typical nitrosamine of tobacco leaves

The invention discloses a method for reducing content of typical nitrosamine of tobacco leaves, comprising the following steps of: filling the tobacco leaves into a supercritical extraction kettle, regulating the extraction kettle, controlling temperature of each separation kettle to be 40-60 DEG C, opening a carbon dioxide steel cylinder, and pressurizing the system through a high-pressure pump; simultaneously, opening an entrainer pump to pump the entrainer, and mixing the entrainer and the carbon dioxide into mixed fluid, wherein the pump is alcohol, acetone or aqueous solution thereof; opening a flow regulating valve after the pressure of the extraction kettle comes up to 10-30 MPa, and regulating rotation frequency of a high-pressure plunger pump to perform pressurized circle extraction. The method provided by the invention has the following benefits that: the content of the typical nitrosamine of the tobacco leaves is reduced by more than 60% after the extraction process, so that risk of cancer to smoke