Instrumental Evaluation of Flesh Texture in Apple Cultivars

抄録

We used instruments to analyze the texture of compressed samples obtained from the equatorial portion of apples cut in radial and tangential directions. The flesh firmness evaluation of apples using a penetrometer (Magness-Taylor type) showed a year-to-year correlation, and this was highly correlated with mechanical values, including maximum force (N) evaluated using two instruments in both the radial and tangential directions. On the other hand, no significant relationship between the mechanical values obtained from the instruments and the sensory test results of flesh texture was observed. We adopted a crispness index (CI) value to characterize the mechanical response during the penetration test. The CI value was not correlated with most of the mechanical parameters in the Rheoner analysis. Additionally, we used a TA.XTplus texture analyzer to obtain mechanical and acoustic responses during the penetration test. The maximum and average acoustic pressures (dB) were not correlated with the mechanical parameters. There was a significant correlation between the acoustic profiles and the CI values obtained from the instruments. These results revealed that the CI and acoustic profiles were physical responses that differed from mechanical ones when measuring the flesh texture of apple fruit. In this study, the CI and acoustic pressure were associated with the sensory test results of flesh texture, suggesting that these parameters were effective for objectively evaluating the flesh texture of apples. The cultivars and selections evaluated as having high crunchiness by sensory test showed relatively high CI values and acoustic pressure. In addition, the CI value showed a significant year-to-year correlation (r = 0.68**), implying that it was one of the genetic characteristics responsible for the flesh texture of apples.