WATERCORE DISSIPATION IN ‘FUJI’ APPLES BY POSTHARVEST TEMPERATURE CONDITIONING TREATMENTS

Apples with severe watercore are rejected during market quality control inspections because affected fruit can develop alcoholic off-flavours and internal browning symptoms.
This work investigates post-harvest temperature conditioning treatments before long term CA storage and ripening inhibitor or promoter treat-ments to accelerate watercore dissipation without excessive loss in fruit firmness.
Late harvest ‘Fuji’ apples with severe watercore were kept in air at 1°C (2008), 3°C (2007), 6°C and 10°C (2007, 2008). Some fruit at 10°C were also treated with 1-MCP and Ethephon.
In 2009, fruit were held in CA at 1, 3, 6°C and in air at 10°C. Additional treatments were 1-MCP 24 h after harvest or non-treatment followed by the respective storage temperatures.
Changes in flesh firmness and watercore were followed during 6 months storage.
Fruit at 1, 3°C in air and fruit at 10°C treated with 1-MCP showed nearly no change in flesh firmness while untreated fruit in air softened by 0.8 kg/cm² at 6°C and around 1.0 kg/cm² at 10°C. Watercore in ‘Fuji’ apples with and without 1-MCP or with ethephon treatments at 10°C dissipated to acceptable levels after around 16 to 22 d, while apples at 1, 3 and 6°C showed acceptable watercore at 51, 29 and 26 d, respectively.
When ‘Fuji’ apples have severe watercore at-harvest, one option is to treat them with 1-MCP and store in air at 10°C for 20 d before CA storage, thus watercore levels will reduce rapidly but fruit flesh firmness will generally be maintained at acceptable levels.
After 3 weeks a significant dissipation in watercore was observed in fruit stored at 3, 6 and 10°C, with the higher temperature treatments negatively correlated with watercore levels.
Due to decreases in fruit quality, by either softening and/or decay incidence, storage at 10°C in air without 1-MCP should not be more than 2 and 4 months with 1-MCP, and no more than 4 mths at 6°C without 1-MCP while 1 and 3°C were unsuitable for 6 months storage without 1-MCP. 1-MCP treatments showed similar effects to the use of CA storage in the maintenance of firmness.
Watercore did not increase the occurrence of other internal physiological disorders.

XXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010): International Symposium on Postharvest Technology in the Global Market

D.A. Neuwald, D. Kittemann , J. Streif, C.A.W. Andrade

1-MCP, fruit firmness, Malus domestica, physiological disorders

https://doi.org/10.17660/ActaHortic.2012.934.147