Proc. of
Effect of Conditioning Temperatures, Intermittent Warming
and High CO2 on Ripening and Chilling Injury Control in 'Hass' Avocado
C. Saucedo-Veloz
Centro de Fruticultura-Colegio
de Postgraduados, Chapingo, Mexico, 56230 Mexico
J.M. Martinez-Javega and M. Mateos-Otero
Institute Valenciano de
Investigaciones Agrarias (IVIA), Apdo. Oficial 46071,
Abstract. The world
volume of avocados exported annually is 100,000 tons. The major export market
is the EEC, however, the long transport distances may result in loss of fruit
quality due to avocado's sensitivity to low temperature storage (chilling
injury). The effect of chilling injury on ripening and quality of the avocado
has been studied, however, certain aspects related to ethylene metabolism
during chilling are still unknown. Recently, techniques have been introduced to
reduce the severity and incidence of chilling injury.
Our
results indicate that two peaks of ACC accumulation occur during ripening. The
peaks coincide with the ethylene peak production and senescence, respectively.
EFE activity diminishes due to chilling injury. This decrease occurs prior to a
decline in ACC synthesis or ACC accumulation. Chilling injury symptoms were
observed after 4 to 6 weeks of storage at 2C and 4 days at 20C. Less chilling
injury was observed when the fruit were conditioned (10C for 1 week + 5C for 1
week + 2C storage) compared to either an intermittent warming treatment (5
hr/week at 20C during 2C storage) or high CO2 exposure (20% CO2
for 1 week at 5C + storage at 5C).