International Journal of Food Engineering.pdfVIP

International Journal of Food Engineering Volume 5, Issue 3 2009 Article 10 Study on Creep Properties of Japonica Cooked Rice and Its Relationship with Rice Chemical Compositions and Sensory Evaluation Su-qiang Chang? Dong Li? Yubin Lan? Necati Ozkan?? John Shi?? Xiao Dong Chen?? Zhi-huai Mao§ ?China Agricultural University, China, changsq@ ?China Agricultural University, China, wlj@ ?USDA-ARS-SPARC, USA, yubin.lan@ ??Middle East Technical University, Turkey, nozkan@.tr ??Agriculture and Agri-Food Canada, Canada, john.shi@agr.gc.ca ??Monash University, Australia, dong.chen@.au §China Agricultural University, China, maozhh@ Copyright c?2009 The Berkeley Electronic Press. All rights reserved. Study on Creep Properties of Japonica Cooked Rice and Its Relationship with Rice Chemical Compositions and Sensory Evaluation? Su-qiang Chang, Dong Li, Yubin Lan, Necati Ozkan, John Shi, Xiao Dong Chen, and Zhi-huai Mao Abstract Creep properties of four varieties japonica cooked rice were tested using a dynamic mechani- cal analyzer (DMA Q800). The creep curve was described by Burgers model. The creep process of japonica cooked rice mainly consisted of retarded elastic deformation, R and viscous flow de- formation, V, and negligible instantaneous elastic deformation, E. The retarded elastic modulus, E2, relaxation time, τ , and the viscosity coefficient, η1, of the cooked rice according to the Burger model were estimated through nonlinear regression. The effect of the chemical compositions on the rheological parameters based on creep behavior of cooked rice was assessed. Correlation analysis indicated that the retarded elastic modulus, E2, had positive correlations with protein (r = 0.952, P = 0.048). The relaxation time, τ , had negative correlation with protein content (r = -0.909, P = 0.091). The viscosity coefficient, η1, was negatively correlated to amylose (r = -0.915, P = 0.085). The analysis between creep parameters and sensory evaluation showed that the viscosity coef