Effects of Milling Ratio and Water‐to‐Rice Ratio on Mastication Effort for Cooked Rice Measured by Electromyography

The objective of this study was to quantify the mastication effort for cooked rice with varying texture. We conducted electromyography ( EMG ) from both masseter muscles while normal subjects ate 6 g of cooked rice. Rice samples were prepared using different milling ratios and cooked with different amounts in weight of water. The texture of cooked rice samples was instrumentally analyzed. Hardness was similar between 2% milled and 1.80 times weight of water, 6% and 1.65, and 10% and 1.50; however, adhesiveness was lower in lesser milled samples. EMG results showed that the number of chews, mastication time and muscle activities per chew were higher in the harder rice samples that were milled less and cooked with less water. When the hardness of cooked rice was adjusted, EMG variables were not significantly different. The mastication effort per gram of solid content significantly differed with milling ratios. Practical Application Cooked rice is a staple food for many people. The texture of cooked rice can be easily modified by changing milling ratios and water‐to‐rice grain ratios. As mastication is the first process of digestion, understanding how milling and cooking conditions influence the texture of cooked rice and mastication behavior is important for palatability and nutrition. EMG variables can provide details on mastication effort, proving to be useful for preparing the best texture of cooked rice. As less milled rice requires more mastication per solid content, it is effective to increase number of chews and to decrease eating rate.