Texture Evaluation of ‘Taishuu’ Persimmon Using an Acoustic Vibration Method

Abstract

Quantitative evaluation of the crisp texture of ‘Taishuu’ persimmon was studied based on an acoustic measurement of crispness (AMC). Measurements of the texture of ‘Taishuu’ persimmon stored for varying days after harvest suggested that the energy texture index (ETI) calculated at frequency bands from 100 to 140 Hz and above 3,200 Hz could be used to quantitatively evaluate the crispness. Measurements of the texture of ‘Kanshu’ persimmon with a different texture from that of ‘Taishuu’ persimmon revealed that there was a significant difference between ETIs of the two cultivars, especially above 4,480 Hz. These results suggest that ETIs with a frequency above 4,480 Hz can be used to quantitatively evaluate the crisp texture of ‘Taishuu’ persimmon. Furthermore, the effects of differences in harvest maturity on the persimmon texture were studied. The ETIs of ‘Taishuu’ persimmon harvested with a color score of 4.5 were lower than those harvested with a color score of 3.5, and corresponded to those of fruit harvested with a score of 3.5 and stored for 7 to 9 days. The crisp texture of ‘Taishuu’ persimmon is an important characteristic. Therefore shipment of the fruit with a color score above 4.5 may lead to a decline in the market rating of ‘Taishuu’ persimmon.