2014 Volume 13 Issue 4 Pages 365-370
The application of an acoustic vibration method for the discrimination of fruit with freezing or granulation of juice sacs (GJS) in Citrus was studied. The elasticity index (EI) of fruit with freezing in blood orange ‘Moro’ was significantly lower than in that without freezing. There was no relationship between the degree of freezing and EI. The specific gravity of fruit significantly decreased as the degree of freezing increased. A relatively strong positive correlation was found between the specific gravity and EI. The discrimination rate of fruit with freezing was approximately 70% when estimated using EI 80 × 105 as a threshold; however, it was approximately 78% when estimated using the specific gravity of 0.88 as a threshold. The EI of fruit with the initial stage of GJS in Hassaku was significantly higher than without GJS. The specific gravity of fruit significantly decreased as the GJS increased. No significant differences were detected among the degree of freezing in blood orange in the total soluble solids content (TSS), but the citric acid in the fruit with a higher degree of freezing was lower than in that without freezing. TSS in Hassaku fruit without GJS was slightly higher than in that with a higher GJS; however, there was no significant difference in citric acid among the degrees of GJS. The results of this study showed that the discrimination of fruit with freezing or GJS in Citrus is possible using a nondestructive acoustic vibration method.
