Relationship between rice components, stress-relaxation and instant rice noodles quality

To simulate the viscoelastic mechanical behaviors of stress-relaxation of rice gel were investigated by studying the correlation of properties of the products, components of raw materials and stress-relaxation parameters, and exploring the effect of components of rice on products of stress-relaxation parameters. Instant rice noodles were prepared of four rice varieties. The results showed that the maximum shear stress, the average shear stress, tensile strength, tensile strain, rehydration and cooking loss of boiling were 0.103-0.184 N/mm2, 0.047-0.066 N/mm2, 0.078-0.157 N/mm2, 53.14%-80.84%, 98.80%-153.26%, 12.09%-24.39%, respectively. Rice with higher protein content and lower fat content revealed higher average shear stress and hardness, lower elasticity and viscosity and lower E1 and η1 (E1 and η1 were the first spring model and dashpot model in extrusion gelatin); higher amylase content resulted in lower percentage of rehydration and cooking loss of boiling, longer relaxation time τ1, and shorter relaxation time τ2, which were key factors in the quality control and evaluation of instant rice noodles. Equations have been interpreted on the basis of relations properties of rice and stress-relaxation parameters. It is not only provide a significant guiding for raw material selection of instant rice noodles, but also explanation quality change mechanism from viscoelastic behaviors of stress-relaxation of rice gel, and provide additional information on the development of starch food.