Ethylene involvement in chilling injury symptoms of avocado during cold storage

Abstract

Application of exogenous ethylene, irrespective of the method of application, caused intensification of mesocarp discoloration in avocado fruit ( Persea americana Mill.) during cold storage of all cultivars tested. ‘Ettinger’ fruit treated with Ethrel (2-chloroethyl phosphonic acid) prior to packing and storage developed severe chilling injury (CI) symptoms, expressed as mesocarp discoloration after 3 weeks at 5 °C. ‘Fuerte’ fruit treated with ethylene gas (100 μl l −1 ) for 24 h at 20 °C prior to storage at 5 °C exhibited mesocarp discoloration, which increased dramatically during shelf life at 20 °C. ‘Fuerte’ fruit treated in cold storage with a continuous low ethylene dose (4 μl l −1 ) developed severe browning in the fruit pulp after 3 weeks at 5 °C. ‘Hass’ fruit treated with 50 μl l −1 ethylene, for 12, 24 or 48 h at 5 °C showed a gradual increase in mesocarp discoloration after 3 weeks in cold storage plus shelf life; the 48 h ethylene-treated fruit exhibited the most severe pulp browning. Use of absorbent sachets that removed ethylene from modified atmosphere (MA) packaging reduced mesocarp discoloration and decay development in ‘Hass’ fruit after 5 weeks storage at 5 °C. Application of 1-methylcyclopropene (1-MCP), reduced mesocarp discoloration, decay development and polyphenol oxidase activity, whereas this enzyme activity was induced in ethylene-treated fruits that were cold stored for 4 weeks.