Deformation profile of a piece of japonica cooked rice with squeezing test

¹ Kobe University, Department of Chemical Science and Engineering, Kobe, Japan
² State University of Jakarta, Department of Home Economics, Faculty of Engineering, Jakarta, Indonesia
³ Kobe University, Organization of Advanced Science and Technology, Kobe, Japan

^* Corresponding author: efrina@unj.ac.id

Abstract

The texture of cooked rice plays an important role in the characteristics of cooked rice. It can be firmness or stickiness depends on the amount of amylopectin inside the cooked rice, the higher the content will be more stickiness. Japonica rice is the type of rice with highest amylopectin content. Therefore the texture is the most stickiness. This research is to define the stickiness of japonica cooked rice using stress-strain behavior through uniaxial compression test. Stress defined as a normal force divided by a cross-sectional area in the horizontal plane while strain as a shrinking ratio of cooked rice. A single Japonica cooked rice squeezed using parallel plate type rheometer with constant velocity (0,2; 0,5; 1; 2; 4 mm/s). The deformation process of cooked rice was recorded from both side and bottom views to measure area transformation. The result showed that stress-strain of the deformation of cooked japonica rice was strongly depended on velocity. The low velocity (0,2;0,5;1 and 1 mm/s) are same with high velocity (2 and 4 mm/s) the during first deformation but significantly different statistically in the later deformation.