Texture of Sliced Cucumbers Measured by Subjective Human-Bite and Objective Instrumental Tests

To determine an effective method to evaluate the texture of cucumbers, human-bite measurement using a multiple-point sheet sensor and instrumental tests using wedge probes with various angles and a cylindrical probe were conducted. To detect small differences in texture, cross-sectional slices taken from the middle part of a cucumber fruit were served at 4 or 22C. The 60°-wedge probe that could completely divide samples like human incisors performed best compared with sharper wedges or cylindrical probe that partly broke the tissue. The human-bite force for cucumber slices of 4C was significantly lower than that of 22C. Breaking force and energy with the wedges of 60 and 30° in the compression test and those for flesh puncture test demonstrated a similar temperature effect. A faster compression speed close to the human-bite speed (20 mm/s) was necessary to detect the significant temperature effects. PRACTICAL APPLICATIONS: The texture of cucumber was analyzed more precisely using a wedge probe with an angle of 60° inserted into sectional slices of the samples similar to the action of human front teeth that completely cut off the section. A cylindrical probe could insert only part of the cucumber tissues and a blade or a sharper wedge probe partially broke the slices to the depth which the probe reached. Faster test speed (>10 mm/s) close to the average speed of human bite is preferred to detect temperature effects on fracture force. If there are some differences in breaking properties of cucumbers, the proposed conditions of compression test with a 60° wedge at 20 mm/s will detect delicate differences as those due to serving temperature were small.