Aerobic-anaerobic metabolic transition in 'Hass' avocado fruits

The aim of this work was to determine the anaerobic compensation point (ACP) in 'Hass' avocado fruits as a function of temperature and the advance in ripening. Controlled atmosphere treatments with oxygen in a range from 0 to 4%, with two temperature levels, 5.5 and 20 degreesC, applied to fruits of three firmness levels which included the pre-climacteric, the mid-zone of the climacteric rise and the post-climacteric phase. Mean ACP values of 1.44% and 1.81% were found for 5.5 degreesC and 20 degreesC, respectively. These values increased with ripening. The production of fermentative metabolites was not exclusive of 02 concentrations below to ACP, and temperature affected the accumulation of these compounds, with values of 10.7 mumol/100mL at 5.5 degreesC and 101.3 mumol/100mL at 20 degreesC. The production of those metabolites significantly increased with ripening and the values were, in the post-climacteric stage, 20 and 39 times greater than in the pre-climacteric one, at 5.5 degreesC and 20 degreesC, respectively. Results obtained here could be used to define adequate storage conditions for 'Hass' avocado fruits in modified atmosphere systems.