Whether you practice organic gardening or not, you must have noticed a greenish tinge on your potatoes during or after harvesting. Potatoes will turn green if exposed to direct sunlight. They produce a green pigment known as chlorophyll at the surface. Production of the green pigment is known as greening. Greening can be seen by looking at a potato or after you start peeling it. The greening is a problem because it produces a compound known as solanine.
Why potatoes turn green
Just like all green plants, potatoes will produce chlorophyll when exposed to sunlight. Chlorophyll is the molecule responsible for collecting energy and making plants green. It is crucial for plants to make their own food through photosynthesis. The more chlorophyll a plant has, the more energy from the sun it can take in and subsequently, the more food it can make and grow successfully. As such, the greening of potato tubers is a strategy to achieve growth success. As long as potato tubers are exposed to the sun, they collect energy from the sun to contribute towards photosynthesis. Unfortunately, the greening can be toxic to humans if consumed.
Solanine in potatoes
Solanine is an alkaloid that is produced in potato tubers, roots, leaves and stalks. It is produced in high quantities in the green tubers that are exposed to direct sunlight. To potatoes, it acts as a pesticide and fungicide to protect it from predators and invaders. However, to humans, it is a toxic substance that can cause gastrointestinal irritation with vomiting is consumed in high quantities.
A completely green potato contains enough solanine to cause serious health complications to anyone who consumes it. In severe cases where solanine has been consumed in very high quantities, a person can become paralyzed or worse still, die. Some symptoms of solanine poisoning include; vomiting, stomach cramping, nausea, dizziness, hallucinations, dilated pupils, delirium, headaches, hypothermia, slow pulses, low sensation, fever and vision problems.
Preventing greening during growth
During growth, ensure that the potato tubers are adequately covered with soil or mulch to prevent sun exposure. Also, give the potatoes enough growth space so that growing tubers do not crowd and get pushed above the surface. Also, ensure that you harvest almost immediately after removing the mulch.
Preventing greening during storage
As a matter of fact, most potatoes green during storage due to poor storage habits and areas. Potatoes should be stored in dark, cool areas like your basement or cellar. Stresses like cold, injury and heat can also lead to the production of solanine.
Handling greened potatoes
There is no reason to use greened potatoes sooner than others or store them longer to detoxify. When preparing potatoes, cut off the greened parts completely and ensure that you do not use too many greened potatoes in one meal. Reduce the risk of solanine poisoning by mixing a few greened potatoes with plenty non-greened potatoes.
Just like all foods, potatoes need to be handled with care. Keep them safe during and after harvesting to avoid future health problems. Also, avoid using a heavily greened potato. Only use ones that clear after a small cut.