Pretreatment process of rice syrup production and analysis of physicochemical properties

A pretreatment experiment of preparing starch syrup with alpha-amylase and twin-screw extrusion together with broken rice of resistant starch rice was studied. Results showed that the content of reducing sugar in the extrudate was 23.52% when the moisture content of the material was 25%, the screw speed was 10 r/min, the barrel temperature was 85 degrees C, and the addition amount of alpha-amylase was 0 U/g. The influence of various factors was ranked as follows: material ratio > screw speed > alpha-amylase addition > barrel temperature. After the extrusion, the contents of starch and resistant starch were not significantly changed, fat content was reduced, and protein and ash contents increased. Starch in the rice was degraded, and the particle structure was destroyed, while the crystal structure changed from type A to type V. Thermodynamic properties and solubility both changed. Rice syrup has a high transparency, good rheology, and a more delicate and soft taste.