Effect of Dropping Practice in Packinghouse Lines on the Quality of Satsuma Mandarin

Abstract

In order to investigate the effects of dropping practice in packinghouse lines on the quality of satsuma mandarin, simulated handling tests were conducted. To evaluate the effect of dropping practice, the changes of gas permeability through the peel and the fruit firmness (force-deformation ratio) during the shelf time for a week or so after dropping treatment were investigated. In conjunction with them, the concentrations of O₂ and CO₂ of the internal atomosphere of the fruit, the concentration of dissolved O₂ in the flesh and the change of dehydro-ascorbic acid (DHA) in the flesh were discussed in detail. Results were obtained as follows.
1. Dropping practice made the gas permeability through the peel increased. It would be due to the mechanical injury by dropping practice which occured in the peel tissues.
2. The firmness of dropped fruit decreased evidently with the increase of repetition of drops.
3. In case of non-dropped fruit, the concentration of O₂ of the internal atomosphere of the fruit was about 19% at the time of harvest and did not change for 20 hours, however, CO₂ decreased gradually from 2.9% to 2.1%. On the other hand, in case of dropped one, O₂ decreased to 17.7% just after dropping practice and increase little by little, but it was always lower than non-dropped one. CO₂ increased to 4.9% just after dropping practice and decreased gradually but it was always higher than non-dropped one.
4. The concentration of dissolved O₂ in the flesh increased evidently with the increase of repetition of drops unless the fruit was waxed after dropping practice.
5. In case of dropped fruit, the ratio of DHA to total ascorbic acid in the flesh increased with the increase of repetition of drops during the shelf time after dropping practice.