The quality of the potato and its storage life is directly impacted by the loss of moisture, decay and physiological breakdown. These deteriorations are directly related to storage temperature, relative humidity, air circulation and gas composition.

by Tudor Vintiloiu

In an attempt to attain the desired storage condition in an enclosure, many systems have been developed over the years depending on the geographic location, volume produced, consumer demand and the marketing strategies. Potatoes, being a living organism, require an effective management for storage.

According to the Canadian Horticultural Council, temperature is the single most important factor in the keeping quality of stored potatoes. For most varieties, temperatures below 3.0oC and above 15.0oC cause dramatic increases in respiration and are not recommended. With certain varieties, such as Shepody, holding temperatures as low as 2.0oC can be tolerated and may be required to control sprouting.

Temperature also has an important relationship with relative humidity (RH). Warm air holds more moisture than cold air. Thus, even small changes in temperature can cause dramatic changes in relative humidity. For the same reason water loss from the tubers is greater at higher temperatures.

The most important biochemical process affected by temperature is the accumulation of sugars, which influences the cooking and processing quality of potatoes. At temperatures below 7.2oC, reducing sugars accumulate leading to dark chips and French fries when the potatoes are processed. At temperatures below 3.0oC the accumulation of sugars is so great that flavor and boiling and baking quality are affected. Potatoes that have sweetened due to low temperatures can be reconditioned to some degree, depending on variety, by raising the storage temperature to 13.0 – 15.5oC for 4-6 weeks before shipping.

Sometimes, it is not easy to foresee weather conditions, potato tuber condition (and quality), store particularities and other factors, which have an influence on the product safekeeping. Automatic systems can easily meet such challenge, maintaining any preset parameters of temperature, humidity, duration of ventilation, heating or cooling and any other.You can read the rest of this article in your complimentary e-copy of the July/August Issue of Potato Processing International magazine, which you can access by clicking here.