Creep deformation modeling of glutinous rice cakes (Mochi)

• Published in: Cereal chemistry 2006-03, Vol.83 (2), p.179-187
• Main Authors: Chuang, G.C.C, Yeh, A.I
• Format: Article
• Language: English
• Subjects: baked goods; Biological and medical sciences; Cereal and baking product industries; creep; extruded foods; extrusion; Food industries; food quality; Fundamental and applied biological sciences. Psychology; mochi; rice cakes; rice products; sensory properties; texture; viscoelasticity; water content
• ISSN: 0009-0352; 1943-3638
• DOI: 10.1094/CC-83-0179

The viscoelastic properties of glutinous rice cakes (mochi) made by extrusion at different conditions (water contents of 45-55% and barrel temperatures of 75-95 degrees C) and commercial rice cakes were studied by a creep test. The maximum compliances of extruded mochi were 0.15-4.23 1/kPa. Among the extruded samples, the mochi extruded at 75 degrees C with a water content of 55% was the one that yielded the largest maximum compliance. At the same barrel temperature, the creep compliance increased with the water content. Four models with different numbers of elements (spring and dashpot) were employed to fit the experimental data. The model coefficients were able to provide the corresponding elastic and viscous behavior of the sample. The 3-element model (a spring in series with a Kelvin-Voigt model) did not exhibit steady-state compliance as observed in the experimental data. The 4-element (Burger's model), modified 4-element (an approximation of Burger's model), and 6-element model (adding one more Kelvin model to the Burger's model) yielded R2 > 0.99. Results showed that the 4-element model was adequate to describe the creep behavior of mochi.