Postharvest factors influencing the development of lenticel spot, bitterpit, and browning disorder in Braeburn apples

In 2001, a pilot study was conducted by Capespan Technology Development to investigate the effect of modified atmosphere packaging (MAP) application, delay in the onset of forced-air cooling (FAC), and cooling rate on the development of lenticel spot and bitterpit post-harvest disorders.  The results indicated that the application of MAP within 3 to 7 days after harvest can reduce financial losses in commercial fruit which are prone to the development of lenticel spot and bitterpit.  A rapid cooling rate (10 h to -0.5°C) and reducing the delay period to 6 h before FAC, decreased the incidence of lenticel spot and bitterpit, compared to a 48 h delay period.

In 2002, the results of MAP application were similar to 2001, although the incidence of the disorders was generally lower than the previous season.  The effect of a delay period before FAC and the cooling rate did not significantly influence the development of bitterpit in 2002.  Lenticel spot levels were higher in rapidly cooled fruit, showing an opposite trend to the results obtained in 2001.

In 2003, laboratory trials confirmed that MAP application within 3 days after harvest reduced lenticel spot levels, but this could not be repeated under semi-commercial conditions. The result is therefore inconclusive, and a final recommendation about the cost-effective implementation of MAP on Braeburn apples cannot be made at this stage.

The rate of FAC did not influence physiological disorder development, and should not be considered as an effective means to prevent lenticel spot or bitterpit manifestation in Braeburn apples.  However, limiting the delay period before FAC, effectively reduced the incidence of lenticel spot in two out of three seasons, and can therefore be regarded as good commercial practice, which may contribute to a reduction in lenticel spot development.