Flow and foam properties of extruded maize flour and its biopolymer blends expanded by microwave.

摘要: Maize flour and blends from starch zein biopolymers were processed as dense materials by extrusion (120°C, 300J·g-1) press-molding (140°C, 10min) at a constant moisture content (26%wb), then foamed microwave heating. The mechanical properties of foams, determined 3-point bending test, governed density, in agreement with an open solid foam model. density 3D cellular structure the foams X-ray tomography. In same interval [0.15, 0.3g·cm-3], microwaved had finer than directly expanded extruder outlet. study melt rheological behavior Rheoplast® (100-160°C, SME≤200J·g-1) showed that protein (0-15%) did not affect shear viscosity but increased elongational viscosity. This trend, similar to one reported for storage modulus rubbery state, could be attributed dissipative effects starch/protein interphase, explaining difference expansion between starch, flour.