Evaluation of Flesh Texture and Development of Flesh Firmness Retention in ‘Soshu’ Persimmon Using Acoustic Resonance Measurement

Abstract

Evaluation of the flesh texture and improvement of the storability of ‘Soshu’ persimmon were studied with acoustic resonance measurement. A significant positive correlation was found between the sensory score on palatability and the elasticity index measured by the resonant frequency. When the sensory score on palatability (ranging from −2: very poor to +2: very good) was 0 or higher, the elasticity index was about 22 × 10⁶ cm²・Hz² or higher, with the fruit immediately after harvest receiving the highest score. 1-Methylecyclopropene (1-MCP) treatment did not affect the maintenance of flesh firmness evaluated by the resonant frequency. However, the rate of softened fruit with collapsed or water-soaked tissue was kept low by 1-MCP treatment, improving the shelf-life. On the other hand, using a moisture-proof corrugated fiberboard box was found to have the effect of retaining flesh firmness. When the sensory score on palatability was 0 or higher for the fruit in the moisture-proof corrugated fiberboard box, it corresponded to the period immediately after harvest to around 10 days after, or about 4 days longer than for the fruit in the conventional corrugated fiberboard box. The weight loss of moisture-proof corrugated fiberboard box fruit was lower than that in the conventional corrugated fiberboard box, which was presumably because water loss from the fruit was suppressed.