Evaluation of Grape Flesh Texture by Acoustic Vibration Method

To clarify the characteristics of grape flesh texture, acoustic vibrations generated by inserting a probe in grape flesh were measured. Texture index (TI) based on energy density, which was calculated from vibration signals, could be used to classify 9 grape cultivars into 3 groups with their flesh textures evaluated as crisp, noncrisp, and intermediate, while breaking force measured by a conventional intrusive method did not. TI of 0–50-Hz band correlated with the breaking force, suggesting that TI of 0–50-Hz corresponds to flesh firmness, and TI of higher frequency characterizes crispness of grape flesh.