Advanced Control of Respiration

Advanced Control of Respiration (ACR) a dynamic form of controlled atmosphere storage for fruit and vegetables.
Difference with classic CA storage
Classic, normal CA/ULO storage stores cultivars under a constant gas condition during the complete harvest season. The advised gas condition is the same for every party of fruit in that same cultivar.
ACR however, only starts with the advised gas condition for a certain cultivar. After that, ACR continuously searches for the lowest possible O2 level (to under 0,2%), just above the point where fermentation starts. It is based on regularly checking the respiratory activity of the fruit.
ACR is considered as a dynamic storage system and measures the respiration of the fruit (Respiration Qu-efficient, RQ).
The CO2 produced, divided by the level of O2 used during a certain amount of time.
Thus, ACR brings significant advantages over normal ULO storage (Ultra Low Oxygen storage), also known as normal Controlled Atmosphere storage.
Energy efficient
A lot of energy can be saved by storing products under ACR-conditions. Whenever an average oxygen value of 0,3% is compared to a standard ULO-condition of 1.5% oxygen(O2), it comes to light that the rate of respiration (breathing) from fruit has declined by 300%. In short, fruit breathes much slower with lower oxygen values.
This means that apples produce three times less heat, which results in far lower cooling costs.
Safer storage
Storing products at the lowest possible oxygen value requires a lot of security for a storage system in order to prevent the fermentation. ACR measures the RQ-value rather than alcohol values.
Therefore, the system is able to react way before the product even starts the production of alcohol. A lower oxygen level creates a higher RQ-value, but no alcohol is produced.
With 0% oxygen, the RQ-value will rise infinitely. This results into an alcohol value of more than 1000 ppb (parts per billion).
Scald prevention
20 years of research on the effect of ACR storage on the quality of apples during shelf life done by the University of Wageningen, has shown that extremely low oxygen (<0.6%) results in retention of firmness and color. Even after two weeks of storage at 18 °C, the positive effects of ACR will still be visible in terms of firmness and taste.
Calibration
Calibration of oxygen and CO2 meters is a requirement for a proper functioning CA installation. Calibration takes place once a week; ACR control systems regulate this automatically, thanks to the three-point-calibration with unique two calibration-ranges (0%-2,5% and 0%-25%). This makes the system one of the safest dynamic systems to exist.

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