Understanding What is the Bitter Tasting Compound in Potato Sprouts and Green Blemishes

November 3, 2025 •

2 min read

Did you know that the bitter taste in potato sprouts and green spots is a natural defense mechanism? This is caused by a compound called solanine, and understanding its risks is crucial for a safe nutritional diet.

Quick Summary

This article explains solanine, the toxic compound in potato sprouts and green blemishes. It details how potatoes produce more solanine when improperly stored, the associated health risks of ingestion, and effective strategies for safe handling and storage to prevent food poisoning.

Key Points

Solanine is the bitter compound: The bitter taste in potatoes with green spots or sprouts is caused by solanine, a toxic glycoalkaloid.
Greening signals potential toxicity: While chlorophyll is harmless, its presence indicates light exposure, which also triggers increased solanine production.
Storage is key: Storing potatoes in a cool, dark, and dry place prevents greening and sprouting, thereby minimizing solanine formation.
Peel and trim for safety: For minor greening, peel the potato and cut away all sprouts and green portions to significantly reduce solanine content.
Discard if very green or bitter: If a potato is very green, has extensive sprouts, or tastes bitter, it should be discarded entirely, as cooking does not eliminate all of the toxin.
Ingestion risks: High levels of solanine can cause food poisoning with symptoms like nausea, vomiting, and headaches; children are more susceptible.

Understanding Solanine: The Bitter Compound

Solanine is a glycoalkaloid poison found naturally in nightshade plants, including potatoes. It acts as a defense against pests and diseases. Normally, solanine levels in healthy potatoes are low, but stress like damage, sprouting, or light exposure increases its production, particularly in the skin, sprouts, and green parts.

The Link Between Green Color and Toxicity

Potatoes turn green due to chlorophyll production when exposed to light. While chlorophyll is harmless, its presence indicates conditions that also increase solanine. Green potatoes suggest potentially high levels of this bitter, toxic compound. A bitter taste is a direct sign of high solanine and means the potato should be discarded.

Health Risks of Solanine Poisoning

Eating large amounts of solanine can cause solanine poisoning. Symptoms vary with the amount consumed and body weight, with children being more vulnerable.

Symptoms of Solanine Poisoning

Symptoms can appear minutes to 24 hours after eating. Mild cases usually pass, but high doses can cause severe issues.

Digestive Issues: Nausea, vomiting, diarrhea, and stomach pain.
Nerve Problems: Headaches, dizziness, confusion, hallucinations, and weakness.
Severe Reactions: Rarely, symptoms include fever, low blood pressure, and hypothermia.

How to Prevent Solanine Buildup

Proper storage and handling prevent solanine buildup, keeping potatoes safe.

Optimal Potato Storage Tips

Store in Dark, Cool Places: Use a pantry or basement.
Ensure Airflow: Use bags or baskets that breathe.
Avoid Refrigeration: Cold can increase sugar content and potentially solanine.
Keep Away from Other Produce: Separate from onions that cause sprouting.
Regular Checks: Discard green or sprouting potatoes.

Salvaging vs. Discarding Potentially Toxic Potatoes

Use this guide to determine if a potato is safe:


Condition of Potato	Recommendation	Reason
Small green spots or sprouts	Peel and remove all green parts and sprouts before cooking.	Solanine is concentrated near the surface.
Extensive greening	Discard the potato.	High solanine levels may be throughout.
Extensive sprouting	Discard the potato.	Indicates high solanine and poor quality.
Bitter taste	Discard immediately.	A strong indicator of high solanine.
Soft, shriveled, or rotten	Discard the potato.	Signs of decay and other risks.

A Balanced Nutritional Approach to Potatoes

Potatoes offer nutrients like potassium, vitamin C, and fiber. Safe handling and storage allow you to enjoy them as part of a healthy diet. Store them properly and discard green or bitter ones to minimize solanine risks.

For more food safety information, visit the Food and Drug Administration (FDA) website.

Conclusion

Solanine is the bitter compound in potato sprouts and green spots, increasing under stress like light exposure. High levels can cause poisoning with digestive and neurological symptoms. Proper storage and inspection are vital to prevent solanine buildup. Peel and trim slightly green potatoes, but discard those that are very green, heavily sprouted, or taste bitter.

Frequently Asked Questions

Solanine is a naturally occurring glycoalkaloid toxin found in plants of the nightshade family, including potatoes. It serves as a natural defense mechanism against pests and diseases.

Potatoes turn green when exposed to light, which stimulates the production of chlorophyll. This green color is a signal that the potato has also likely produced higher levels of the toxin, solanine.

Not necessarily, but the green color is a strong indicator of elevated solanine levels, which can be toxic if consumed in large quantities. It is safer to remove green parts or discard the potato if the greening is extensive.

Cooking methods like boiling or frying only partially reduce solanine content. The most effective way to lower the toxic compound is to peel the potato and remove any green or sprouted areas.

If a potato tastes bitter or causes a burning sensation in your mouth, do not eat it. This is a key sign of high solanine concentration, and the potato should be discarded immediately.

Small sprouts can be removed, but if a potato has extensive sprouting, it is best to discard it. High concentrations of solanine are found in sprouts, and they indicate that the potato is aging and likely stressed.

Store potatoes in a cool, dark, and dry place with good ventilation. Avoid keeping them in direct sunlight or the refrigerator, and store them separately from onions.