Picking date recommendations for air and CA storage of Braeburn
The picking date recommendations provided below were developed from a 3-year project (2003-6) funded by the HDC (project TF152). It is clear from data obtained in all years of the study that the picking ‘window’ is quite narrow for Braeburn. The following criteria were used to identify the optimum harvest date:
- Avoidance of scald
- Background colour maximum score of 2 (light green) on WWF colour chart
- Firmness minimum of 6.8 kg at despatch
- Greasiness maximum score of 1 on 0-5 scale
It was reassuring that over the 3 years the starch iodine test could be used to indicate optimum time of harvest. Firmness was too variable between the years to be of use as a guide to harvest date and there was little change in soluble solids concentrations over the harvesting period. Starch levels suggested for optimum storage quality are as follows:
|
|
Starch |
|
|
|
% surface black |
Ctifl 1-black, 10-white |
|
Air storage December |
85-75 |
3-5 |
|
CA storage January |
85-75 |
3-5 |
|
CA storage March |
80*-75 |
4*-5 |
* Lower starch coverage required to reduce risk of superficial scald
Picking according to these starch criteria generally provided the best eating quality in each of the years.
Picking earlier than indicated by starch levels is likely to lead to poor appearance, loss of eating quality and wastage due to scald development. Later harvesting will lead to greasiness, loss of appearance and eating quality and is only appropriate for shorter term storage.
