Before being consumed or processed, potatoes are kept for different periods to provide a year-round supply for both consumers and the processing sector.

By putting some of the crop in storage, processing facilities may remain open all year round, the market is kept from being oversupplied during harvest, and fewer potatoes need to be imported from other climatic zones.

Potato tubers may be successfully stored for a year or more with careful handling. But in actual commercial use, the duration of storage often varies from a few weeks to several months.

Although the respiration rate of well-stored, dormant potato tubers is rather low, several factors like warm temperatures, stress, injury, physiological age, and ethylene can cause the respiration rate to increase. Respired CO2 in a bin of stored tubers will accumulate quickly if not removed by ventilation.

“CO2 concentrations which greatly exceed ambient levels can easily occur in potato storage bins, accompanied by depletion of O2. Observations of 1 to 4% CO2 in the storage headspace are not unusual, with levels exceeding 10% reported occasionally,” private consultant Barbara Daniels-Lake wrote in one of her research papers.

Potato tubers that are exposed to moderate or high CO2 concentrations (3 to 30%) exhibit both stimulated and inhibited respiration. Even though the strength of the reactions varies slightly with temperature, these effects last for several days following exposure. Researchers discovered that higher CO2 levels (5, 10, and 15%) lessen suberization. Depending on how mature the tubers are, elevated CO2 can either promote or prevent sprouting. Sprouting is inhibited by elevated CO2 and relatively low O2 concentrations, or by classically regulated atmospheric conditions. Tissue necrosis can result from exposure to CO2 concentrations higher than 10%.

CO2 Management’s Parallel Development With the Potato Processing Industries

In the potato processing sector, the consensus has long been that processing color darkening is caused by accumulating CO2 in the storage environment. It has frequently been advised to keep the CO2 content in the storage environment below 1 or 2% CO2.

Researchers involved in recent studies discovered that low-temperature sweetening (LTS) is prevented by exposure to 2 to 5% CO2. According to their findings, some cultivars of potato chips are mostly unaffected by 2 to 3% CO2, although at a greater concentration (13%) the reduced sugar concentrations rise.

You can read the rest of this article in your complimentary e-copy of Issue 2 of Potato Business Digital 2024 magazine, which you can access by clicking here.