Non-fried sweet potato crisps and preparation method thereof

The invention discloses non-fried sweet potato crisps and a preparation method thereof. The method comprises the following steps of: placing sweet potato crisp pulps in a puffing tank and carrying out variable-temperature differential-pressure puffing to obtain puffed sweet potato crisps; and the variable-temperature differential-pressure puffing comprises the following steps of: (1) raising the temperature in the puffing tank to 100-120 DEG C, raising the pressure to be 0.1-0.3MPa higher than the atmospheric pressure outside the puffing tank and keeping the temperature and the pressure to ensure that the surface temperature of the sweet potato crisps is consistent with the temperature in the puffing tank; (2) reducing the pressure in the puffing tank to a vacuum state, reducing the temperature to 90-100 DEG C under the vacuum state and keeping the pressure and the temperature under the vacuum state to ensure that the water content of the sweet potato pulps is 3-5%; and (3) reducing the temperature in the puf