PH—Postharvest Technology: Firmness Changes of Pear Fruit before and after Harvest with the Acoustic Impulse Response Technique
✍ Scribed by N. De Belie; S. Schotte; J. Lammertyn; B. Nicolai; J. De Baerdemaeker
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 167 KB
- Volume
- 77
- Category
- Article
- ISSN
- 0021-8634
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✦ Synopsis
The non-destructive acoustic impulse response method was evaluated for monitoring "rmness changes of Conference and DoyenneH pears on the tree. The correlation between "rmness and meteorological factors was investigated during two successive years. In both years, the "rmness showed a sudden reduction between three weeks and one week before harvest to about 23 kHz g for Conference and on average 31)5 kHz g for DoyenneH pears. Afterwards the "rmness decrease could be described by a "rst order model, which allows to estimate the optimum harvest date, corresponding to a "rmness of about 20}21 kHz g for Conference and 26}27 kHz g for DoyenneH . Especially for DoyenneH pears the correlation between the non-destructive "rmness and the destructive penetrometer "rmness was high (correlation coe$cient "0)82). Also the soluble solids contents was reasonably well (negatively) correlated with the "rmness measures ( "!0)60 to !0)79). Pears that were harvested too early never reached an acceptable quality for consumption. Especially Conference pears stored at a low relative humidity developed weak necks. On the other hand, when pears were picked late, the rates of "rmness degradation and weight loss increased. None of the measured meteorological parameters (temperature and rainfall) consistently provided a signi"cant improvement of the predictive "rmness model.