Preparation of recombinant rice with low glycemic index whose raw material is slowly digested starch

A method of preparing low-glycemic index slowly digestible starch-based reconstituted instant rice, comprising:

• (i) humidifying broken rice with water sprayed at a temperature of 25° C. to 30° C.,
• (ii) drying the broken rice,
• (iii) subjecting the broken rice to a solid-state non-crystallization treatment, which comprises fluidizing the broken rice with a high-temperature fluidization machine, wherein the broken rice has a degree of gelatinization of 65% to 85% after fluidizing,
• (iv) pulverizing the broken rice into 80 mesh to 100 mesh rice flour,
• (v) hydrolyzing the 80 mesh to 100 mesh rice flour by addition of protease,
• (vi) extrusion molding the hydrolyzed 80 mesh to 100 mesh rice flour, which comprises extruding by a twin-screw extruder at a solid feed rate of 2 kg/h to 5 kg/h before initiating extrusion,
• wherein extruding is performed at four temperature stages comprising 55° C. to 65° C., 65° C. to 75° C., 75° C. to 85° C., and 85° C. to 110° C.,
• wherein the twin-screw extruder is operated at a screw speed of 70 rpm to 110 rpm,
• wherein the twin-screw extruder comprises a die and a die pore comprising an extruder discharge port having a diameter of 4 mm to 8 mm,
• wherein the discharge port has a cutter speed of 200 rpm to 250 rpm,
• wherein anhydrous acetic anhydride is added at 3% to 6% (w/w) of the rice flour at temperature stage 65° C. to 75° C. and at a constant rate of 0.5 mL/min to 2 mL/min, and
• wherein material extruded from the die is cut to obtain granular or spherical or rod-shaped particles with a particle size of 4 mm to 6 mm,
• (vii) drying the particles by a hot air fluidized bed, and
• (viii) cooling the particles.