Abstract
The differences in cutting operations with kitchen knives were quantified, and damage to food materials caused by cutting was evaluated. The following two types of cutting operations were investigated : “straight-down cutting” (i.e., holding the knife perpendicular to the cutting board and forcing the handle straight down) and “push cutting” (i.e., forcing the knife forward and downward, tracing a parallelogram). An onion was cut into ∼0.3-cm-thick slices by two knives of different sharpness using the two types of cutting operations, and the cutting load values were recorded. The cutting load values during push cutting were smaller than those during straight-down cutting with both knives. The lowest cutting energy was recorded in the case of push cutting with the sharp knife (1.5×102 J/m2). On the other hand, the highest cutting energy was recorded in the case of straight-down cutting with the dull knife (8×102 J/m2). To evaluate damage to food materials, the amounts of onion juice and pyruvic acid, which can be used as an index of pungency, flowing from the cut surfaces as well as the roughness in 3D images of the cut surfaces observed under a digital microscope were quantified. When the cutting energy was low, these three measures were small. These results indicate damage to the cut surface caused by cutting operations is low when the cutting energy is also low.
