Some Science

ON LOW OXYGEN FRUIT STORAGE

 

LOW OXYGEN STORAGE

Low Oxygen storage is now at the forefront of fruit storage for apples and pears. 

For optimal storage results fruit should be stored just above, but as close to the fruit's Low Oxygen Limit (LOL) as possible (typically below 0,7% for apples and pears). Storing at low oxygen levels can provide significant benefits compared to conventional controlled atmosphere (CA) storage. These benefits include control of superficial scald, improved colour and taste retention and significantly extended storage life. 

Fruit from different cultivars, seasons and growing regions have different LOL's.

Storing at oxygen levels below the fruit's LOL may result in unwanted fermentation which is detrimental to fruit. It is very important to be able to accurately and reliably determine the LOL and store just above this level. 

WHAT IS DYNAMIC CONTROLLED ATMOSPHERE (DCA)?

Dynamic Controlled Atmosphere searches for the Low Oxygen Limit, by adapting oxygen levels dynamically during the storage period and is based on a measurement of a biological response of the stored fruit under low oxygen conditions. – Zanella 2003

Requirements for DCA-CF

  • Well sealed CA rooms (Pressure drop from 25 to 188mm water gauge in longer than 30 minutes);
  • Adequate on-site Nitrogen supply;
  • High performance CO₂ scrubbers that can operate at low CO₂ levels without adding Oxygen to the CA store.

 

HARVESTWATCH DYNAMIC CONTROLLED ATMOSPHERE – CHLOROPHYLL FLUORESCENCE

The HarvestWatch Dynamic Controlled Atmosphere system allows operators to reliably detect the Low Oxygen Limit in fruit and to store safely with confidence at optimal low oxygen levels.

The HarvestWatch system directly measures the fruits response to low oxygen conditions by analysing the fluorescence intensity emitted from the chlorophyll in the skin of the fruit.

If the oxygen levels in the storage room become too low, the system indicated the fruit stress and allows for corrective measures to be taken.