Recently the preparation of biodegradable materials using proteins from wheat

soy and corn has been widely studied due to their excellent cohesive

viscoelastic and gas barrier properties.The present work mainly focuses on the influences of starch and moisture contents on the dynamic rhelolgical behavior and uniaxial extensional deformation of glycerol plasticized gluten-starch composites.Wheat gluten

wheat starch and glycerol

compounds with weight ratio of 21:0P9

18:3:9

15:6:9

and 12:9:9

respectively

were prepared by using a three-roll mixer.The compounds were molded into rectangle or dumbbell-shaped samples of 2 mm in thickness and 6 mm in width at room temperature.The dynamic behaviors of the mixtures were investigated using an Advanced Rheometeric Expansion System (ARES) at 0.1% strain and 30℃.The tensile test was performed on a universal testing machine with an extension rate of 20 mm min-1.The results showed that the dynamic storage modulus (G′) of the composite increased with increasing starch fraction.The plasticized gluten forms a crosslinking network at 80℃ due to chemical reaction.The results of temperature scan revealed a “rubber plateau" at temperatures above 100℃.The starch gelatinization was not observed upon heating the composites.It indicates that moisture mainly exists in the glycerol-rich region

and the starch granules act as inert fillers.The dynamic frequency sweep shows that the composites exhibit gel-like behavior at 30℃.A marked “second plateau" appears in the low frequency region

which reveals strong physical interactions between the starch particles and the protein matrix.The interactions between polar groups in starch and protein both lead to the formation of a physical network additional to the chemical crosslinked protein network.The results of uniaxial extensional deformation tests show that the tensile strength and the elongation at break decrease with increasing the starch fraction in samples with 10% moisture.On the other hand

opposite results were observed in the composites containing 20% and 25% moisture

which could be ascribed to the dilution and lubrication between the starch granule and the gluten network by moisture.