Instant whole wheat crisps and preparation method thereof

A method of preparing an instant whole wheat crisp, comprising:

• using whole wheat grains as raw materials, fully soaking the whole wheat grains to make the whole wheat grains absorb water until saturating, and then performing steam cooking above water, extruding, sheeting, and microwave vacuum drying to obtain the instant whole wheat crisp,
• 1) wherein the fully soaking comprises:
• completely submerging the whole wheat grains in water until a water content of the whole wheat grains exceeds 35 wt. %;
• 2) wherein the steam cooking above water comprises:
• steaming the whole wheat grains treated in the step 1) above the water for 5-25 min;
• 3) wherein the extruding comprises:
• adding the whole wheat grains steamed in the step 2) to a twin-screw extruder for extrusion treatment, while the whole wheat grains are hot, and obtaining a noodle-like extrudate:
• 4) wherein the sheeting comprises:
• pressing the noodle-like extrudate obtained in the step 3) into a sheet having a thickness of 1 mm and a width of 14.5 cm, and further cutting the sheet into various shapes;
• and
• 5) wherein the microwave vacuum drying comprises:
• evenly spreading the sheet after cutting in the step 4) on a tray, sending the tray into a microwave vacuum dryer, and drying for 10-30 minutes to obtain the instant whole wheat crisp.