CONTAINER ATMOSPHERE, AS INFLUENCING SOME PHYSIOLOGICAL BROWNING MECHANISMS IN STORED FUERTE AVOCADOS

Authors:	J.P. Bower, A.B. Truter, J.G.M. Cutting
Abstract: Stored avocado fruit often show an unacceptable incidence of storage disorders. Modification of the storage atmosphere is known to alter disorder incidence, but the manner in which the treatments affect the polyphenol oxidase (PPO) browning mechanism is unknown, making research into improved storage techniques arbitrary. The effect of controlled atmosphere, CO₂ "shock" and normal atmosphere storage on PPO activity was evaluated. 'Fuerte' fruits were stored for 28 days at 5.5°C, under 2% oxygen 10% carbon dioxide (controlled atmosphere); 25% carbon dioxide for 3 days commencing 1 day after harvest followed by normal atmosphere (CO₂ "shock") and normal atmosphere (control). Both treatments showed a lower incidence of physiological disorders than the control. PPO activity was lowest in the CO₂ "shock" and highest in controlled atmosphere fruit. Total phenols tended to be lower in CO₂ "shock" fruit as compared to other treatments. Abscisic acid results indicated that fruits in controlled atmosphere storage may be subject to lower post harvest stress than fruit from other treatments, and were in a physiological state similar to that at harvest, after 28 days storage. Further research into the effects of controlled atmosphere storage is required.
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