How to store potatoes in the fridge?

In this brief guide, we will answer the query, “How to store potatoes in the fridge?”  and will discuss how to properly store potatoes.

How to store potatoes in the fridge?

To store the potatoes in the fridge partially or fully cook the potatoes. Once they are cooked, the browning enzymes are deactivated, preventing them from discoloration.

How Should Potatoes Be Stored?

Potatoes have been a mainstay in many civilizations for over 10,000 years. They’re also a good source of carbohydrates and fiber, making them a nutritious complement to any meal. Baked, boiled, roasted, fried, or dried are the most common methods of cooking these delicious tubers. Longer shelf life and less waste may both be achieved via the use of proper storage.

Potatoes contain toxic compounds called glycoalkaloid, which has caused illness and even death in people, livestock, and farm animals. Growth conditions, maturity, variety, fertilization, early harvest, temperature extremes before and after harvest, exposure to light, mechanical damages such as cutting and slicing following harvest and sprouting are the factors affecting the amount of this toxin (1).

Store potatoes in a cool place

Preserving the freshness of potatoes by keeping them in a cool place is an important factor in their longevity. Potatoes may be kept at a temperature of 43–50°F (6–10°C) for months without deteriorating.

There are a few places where this temperature range may be found, including cellars, basements, and garage or shed cool rooms. One of the earliest indicators of spoiling is the production of sprouts on the skin, which may be delayed by storing potatoes under these circumstances.

When compared to room temperature storage, one research revealed that keeping potatoes at low temperatures almost tripled their shelf life. However, the temperature should not be below 5°C (41°F). As a living organism, potato tubers require energy through respiration and respiration rate increases with temperatures above 15°C (59°F) and below 5°C. The respiration rate increases slowly up to about 15◦C above which respiration begins to increase sharply. Reducing the temperature to 3◦C also results in a sharp increase in respiration due to the high concentration of reducing sugars formed by the breakdown of starch. The activity of the enzyme invertase, which hydrolyzes sucrose into glucose and fructose, is also high at lower storage temperature (2).

Vitamin C is better preserved when stored at lower temperatures. The vitamin C content of potatoes held at cold temperatures remained stable for four months, but potatoes housed in warm rooms lost over 20% of their vitamin C content in one month, according to research. The vitamin C content declines rapidly up to 2–3 months of storage and after that, its content decreases slowly until the end of storage. 24% drops after 2 months, 45% drops after 4 months and 52 % drops after 7 months, approximately, at 4°C (39°F) (3).

Vitamin C content may be preserved and shelf life extended by storing food at temperatures just above freezing.

Avoid Exposure to Light

Potato skins may develop chlorophyll and turn into an unwelcome green tint when exposed to sunlight or fluorescent lighting. Greening of tubers occurs when they are exposed to light intensities as low as 3–11Wm−2 for a short period of as low as 24 h (2). Toxic chemical solanine, or glycoalkaloid, may be produced by sun exposure despite chlorophyll’s beneficial effect on the skin.

Green potatoes are sometimes thrown away because of the greater quantities of solanine they contain. As a result, persons who are sensitive to solanine taste it as bitter and have a burning sensation in the mouth or throat. Solanidine can cause off-flavors on cooking at concentrations of 15–20 mg per 100g and impart a bitter taste (2).

Solanine may also produce nausea, vomiting, and diarrhea if ingested in large amounts. Even fatalities have been recorded in a few instances. Solanine levels in commercial potatoes are typically limited at 91 mg per pound (200 mg/kg) in many countries, therefore this is not a widespread issue.

Most of the solanine in tomatoes is found in the peel and the first eight millimeters of the flesh. Most of it may be removed by carefully slicing and dicing the skin and the green meat underneath it.

In addition, light and mechanical damage were reported as being the most important environmental stress agents on the synthesis of glycoalkaloid in the potato tubers after the harvesting (1).

Raw potatoes should not be kept in the refrigerator or freezer.

Refrigeration and freezing are not recommended methods for storing potatoes, since cool temperatures are preferable. Temperatures below freezing might trigger “cold-induced sweetening,” which is a common side effect. When starch is transformed to reduce sugars, this occurs.

Studies revealed that potato tubers stored at temperatures below 9–10°C (50°F) result in high concentrations of reducing sugars such as glucose and fructose known as low-temperature sweetening. These reducing sugars participate in the Maillard browning reaction with free amino acids during frying resulting in dark-brown-colored fries and chips. These darkened chips and fries are unacceptable to consumers and also may result in greater amounts of acrylamide production which has been linked to many cancers (2).

Carcinogenic acrylamides are formed when reducing sugars are cooked at high temperatures, thus it’s preferable to keep the amounts low. Potatoes that have not been cooked should never be placed in the freezer.

The water in potatoes swells and crystallizes when exposed to cold temperatures, causing the cell walls to dissolve. When they are defrosted, they become mushy and useless. When stored in the freezer, raw potatoes may also become brown due to exposure to air. The storage at 0–2°C (32°C) or below increases the risk of freezing or chilling injury. Usually potatoes that are chilled look sound when removed from low temperature (2).

These enzymes, which are responsible for the browning of potatoes, remain active even at freezing temperatures. Even after they’ve been partially cooked, they may be frozen since heating deactivates the browning enzymes and keeps them from becoming brown. 

Phenolic compounds are associated with the color of raw potatoes and certain types of discoloration in processed potato products. In normal uninjured potatoes there is no oxidation of the phenolic substances such as to form discoloration products. When potato tubers are injured by bruising, cutting or peeling, the phenols are rapidly converted to colored melanins due to oxidation of phenolic compounds by enzyme phenolase (2).

Place in a Paper Bag or a Disposable Bowl

When potatoes are kept in a dark, wet environment, they are at risk of rotting. A paper bag or open bowl is the best approach to keep the air flowing freely. You should not keep them in a zipped plastic bag or closed glassware that is completely blocked off from the air.

Moisture from the potatoes will condense within the container and encourage the development of mold and germs if there is no air movement. It is also important to have a steady supply of fresh air during storage to provide the oxygen needed in respiration and to remove CO2 released during respiration. Excessive accumulation of CO2 may cause blackheart eventually resulting in rot and also affect the processing quality of stored potatoes by affecting the chip color (2).

Do not wash the potatoes before storing

Potatoes often have dirt on their skins due to their subterranean cultivation. While it’s tempting to clean them up before storage, it’s best to let them dry to avoid deterioration. Washing increases moisture, which encourages the development of germs and fungus.

In addition, washing may lead to injury of the tubers, which causes the increasing production of solanine (2).

Rinse and clean them with a vegetable brush when you’re ready to use them to eliminate any lingering dirt. Rinsing with a 10% vinegar or salt solution may eliminate more residue than rinsing with water alone if pesticides are a concern.

Prevent contact with Other Produce.

Ethylene gas is released during the ripening process of many fruits and vegetables, which aids in the softening and elevation of sugar content. Ripening food may speed up the sprouting and softening of uncooked potatoes if they are kept near together.

On the other hand, ethylene is a very effective sprout inhibitor, however, its use may result in darkening of fry color. In a study carried out to minimize the effect of ethylene on fry color, it was observed that continuous ethylene treatments inhibited sprout growth (2).

As a result, avoid storing potatoes near ripening fruits and vegetables such as bananas, apples, onions, and tomatoes, which all emit significant levels of the hormone ethylene. It’s unknown how far potatoes should be kept away from maturing fruits and vegetables, but keeping them on different ends of a cold, dark, well-ventilated pantry seems to work.

You can increase the shelf life of homegrown potatoes by “curing” them before storing them. Curing is a normal practice after potato harvested to promote dormancy and extend postharvest storage life, by preventing decay caused by microorganism during storage. Studies showed that curing at 15°C (59°F) for 14 days in dry conditions reduced the incidence of skin spot from 70% prick wounds infected down to 4% (4).

Most people buy their potatoes from the grocery store, but you can do it yourself and save money. Temperatures of 65°F (18°C) and humidity levels of 85–95% are required for two weeks for curing.

Using a 40-watt light bulb and an empty oven with the door slightly ajar, you can generate heat and humidity in a tiny, dark closet or a stand-up shower. When stored in these circumstances, the skins become thicker and more resistant to decay since any small injuries that happened during harvesting may be healed. 

 For long-term preservation, keep cured potatoes in a cool, dark room with plenty of air circulation.

Other FAQs about Potatoes that you may be interested in.

how to cut potatoes into wedges

Can sweet potatoes be peeled ahead of time?

Can deer eat potatoes?

Are potatoes healthier than rice?

Conclusion

In this brief guide, we answered the query, “How to store potatoes in the fridge?”  and discussed how to properly store potatoes.

References

1. Şengül, M., F. Keleş, and M. S. Keleş. The effect of storage conditions (temperature, light, time) and variety on the glycoalkaloid content of potato tubers and sprouts. Food Contr, 20004, 15, 281-286.
2. Pinhero, Reena Grittle, Robert Coffin, and Rickey Y. Yada. Post-harvest storage of potatoes. Advances in potato chemistry and technology. Academic press, 2009. 339-370.  
3. Külen, Oktay, Cecil Stushnoff, and David G. Holm. Effect of cold storage on total phenolics content, antioxidant activity and vitamin C level of selected potato clones. J Sci Food Agric, 2013, 93, 2437-2444.
4. Wang, Qingguo, et al. Effects of postharvest curing treatment on flesh colour and phenolic metabolism in fresh-cut potato products. Food Chem, 2015, 169, 246-254.