Chilling injury in stored eggplant fruits of different maturities
1993
Turnos, N.A. (Southern Mindanao Univ., Kabacan, Cotabato (Philippines). Dept. of Horticulture and Plant Breeding)
Eggplant 'Dumaguete Long Purple' fruits exhibited chilling injury (CI) when kept for 6 days (d) or more at 0 deg C and 10 d or more at 5 deg C. The injury was characterized by surface pitting and scald, browning of seeds, pulp, pitted and adjacent areas. CI was more severe and symptoms occurred earlier in fruits at 0 deg C than at 5 deg C. Subsequent transfer of fruits at 25 deg C after 6 or 9 d storage at 0 deg C did not aggravate the extent of surface pitting but this intensified the browning of seeds and pulp. On the other hand, the effect of chilling temperature was still reversible when fruits were kept for only 3 d at 0 deg C before transfer to 25 deg C. CI in fruits was associated with high and rapid moisture loss resulting in deformation and collapse of subsurface cells which consequently resulted in surface pitting of fruits. It was also characterized by low rate of respiration and ethylene production. However, the rate of increase was more rapid at 0 deg C than at 5 and 10 deg C. Increase in respiration rate was associated with the development of CI. Polyphenoloxidase (PPO) activity and total phenols increased before and at occurrence of the injury symptoms. The increase in both activity and levels of PPO accounts for the browning at chilling temperature. CI symptoms appeared 1 d earlier and the injury was more severe in immature than in mature fruits. Consequently, storability was 2-3 d shorter in the immature fruits. Mature fruits stored at 0 deg C can be kept in good condition for only 12-15 d due mainly to CI. Storability was extended to as long as 26-28 d without CI at 10-15 deg C and 23-25 d at 5 deg C to slight CI. At 20 deg C and above, storability was only 8-9 d, while in fruits kept at 0-15 deg C for 9 d before transfer to 25 deg C, 7-12 d
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