ISHS Acta Horticulturae 553: IV International Conference on Postharvest Science
RIPENESS OF SHADED AND SUN-EXPOSED APPLES (Malus domestica) |
| Authors: | J.D. Klein, L. Dong, H.W. Zhou, S. Lurie |
| Keywords: | Ethylene, ACC, firmness, CO2 , titratable acidity, soluble solids |
| DOI: | 10.17660/ActaHortic.2001.553.13 |
| Abstract:
We investigated the effect of preharvest temperatures in the orchard during commercial harvest on ripeness characteristics of shaded and sun-exposed apple fruit. A recording thermocouple and an external collection apparatus were attached to individual fruits to measure temperature and ethylene and carbon dioxide production on the tree. Sun apples were 5-10°C warmer than shade fruit, and had a diurnal pattern of both ACC and ethylene production with a mid-day peak. Shaded apples produced 80-90% less ethylene than did sun-exposed fruit. Respiration (CO2 production) in both exposed and shaded fruit was lowest in the morning and increased during the day. At harvest, exposed fruits were firmer and had higher soluble solids than shaded apples. These differences diminished when fruit were kept for 10 days at 20°C after harvest. The diurnal temperature flux in the orchard hastened some ripeness parameters (ethylene production and soluble solids accumulation) while delaying softening. The transient heat stress that sun-exposed apples experienced in the orchard was not the same as a postharvest heat treatment that delayed ripening. | |
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