Preliminary investigation into the uneven ripening of banana (Musa sp.) peel

Mature green bananas (Musa sp., AAA group, Cavendish subgroup, cultivar 'Williams') were used to examine the uneven de-greening of banana peel treated with 1-methylcyclopropene (1-MCP). After ethylene treatment (200 mu l litre(-1) for 24h at 20 degrees C) bananas were allocated different treatment units: 1-MCP treatment (200 nl litre(-1), 20 degrees C, 24h); nitrogen treatment (O-2<0-1%, 20 degrees C, 24 h); ethanol treatment (0.3 ml litre(-1), 20 degrees C, 24 h); chilling treatment (1 +/- 1 degrees C, 24 h); and untreated control (20 degrees C). After these post-ripening treatments (24 h), fruit were stored in perforated plastic bags at 20 degrees C. Ethylene, respiration, ethanol and acetaldehyde production, skin colour, chlorophyll fluorescence, chlorophyll content, and flesh firmness were assessed at regular intervals. The post-ripening nitrogen atmosphere and chilling treatment (24h) led to a transient delay of ripening compared to ethanol-treated fruit and untreated control fruit. However by I week of shelf life at 20 degrees C, there were no differences between non-1-MCP treated fruit. No differences in the accumulation of acetaldehyde and ethanol were detected during storage. Ethylene production was not affected by the 1-MCP treatment 24 h after initiating ripening. However peel de-greening, the decrease in chlorophyll content and chlorophyll fluorescence were delayed with 1-MCP treatment. There was some general browning throughout the 1-MCP treated peel in both the green and yellow areas of the ripening peel. It appears the 1-MCP treated peel 24 h after ethylene treatment may still undertake some normal senescence that occurs during banana ripening.