How to get rid of solanine in tomatoes?

November 5, 2025 •

4 min read

While tomatoes are a beloved fruit, they belong to the nightshade family, and their unripe, green parts contain a natural toxin known as tomatine, which is structurally similar to solanine found in potatoes. Learning how to get rid of solanine in tomatoes is actually about safely handling the tomatine content, primarily by allowing the fruit to ripen completely, which naturally diminishes the toxin.

Quick Summary

The best way to eliminate toxic alkaloids in tomatoes is through ripening, as the concentration of tomatine decreases dramatically as the fruit matures. Proper handling, storage, and cooking methods are also important strategies to minimize risk, especially when dealing with unripe green tomatoes.

Key Points

Prioritize Ripening: Allow green tomatoes to ripen fully, as this is the most effective way to eliminate tomatine, the primary glycoalkaloid in the fruit.
Use Ethylene Gas: Speed up the ripening process for mature green tomatoes by placing them in a container with a banana or apple, which releases ethylene gas.
High-Heat Cooking is Best: Deep-frying at temperatures above 170°C can help reduce glycoalkaloid levels more effectively than boiling.
Avoid Unripe and Bitter Tomatoes: Steer clear of immature, hard, or bitter-tasting green tomatoes, as these contain higher concentrations of alkaloids.
Discard Damaged Parts: Always throw away any bruised, moldy, or rotting parts of a tomato, as well as the leaves and stems of the plant.

Understanding Solanine and Tomatine in Tomatoes

Tomatoes, as members of the Solanaceae (nightshade) family, contain natural compounds known as glycoalkaloids. While potatoes are known for containing solanine, the primary glycoalkaloid in unripe tomatoes is tomatine. Both compounds serve as the plant’s natural defense mechanism against pests and disease. The concentration of these alkaloids is highest in the plant’s leaves, stems, and immature green fruit, but the levels in the fruit decrease significantly as it ripens. For most people, the amount of tomatine in a fully ripe tomato is negligible and poses no health risk. However, higher concentrations in unripe green tomatoes can cause mild gastrointestinal distress if consumed in large quantities.

Ripening Is the Most Effective Solution

The most important strategy for minimizing tomatine in tomatoes is simply to let them ripen. As the tomato transitions from green to its final ripe color (red, yellow, or orange), the plant's natural metabolic processes break down the tomatine, making the fruit safe and delicious to eat.

How to ripen green tomatoes indoors: If your growing season ends before your tomatoes have ripened, you can bring them inside. Place green, mature-sized tomatoes in a paper bag or a cardboard box.
Use the banana trick: To speed up the ripening process, add a ripe banana or apple to the container with the green tomatoes. These fruits release ethylene gas, a natural plant hormone that encourages ripening.
Ensure good airflow: When ripening indoors, avoid stacking tomatoes and make sure there is good air circulation to prevent mold.

Cooking and Preparation Methods

While ripening is key, certain cooking methods can also help, though they are not a substitute for proper maturation. It's a common misconception that boiling completely removes these toxins, but studies show glycoalkaloids are heat-stable and boiling only offers a minimal reduction. Some evidence suggests high-heat methods may offer better results.

Deep-frying: High-temperature frying, above 170°C (338°F), can break down some glycoalkaloids. This is why fried green tomatoes, typically made with a batter, are a popular and relatively safe dish to enjoy in moderation.
Frying vs. Boiling: It's important to remember that frying reduces the toxin more effectively than boiling, which is why making a large batch of boiled green tomato pickle, while popular, does not guarantee a significant reduction in alkaloid levels.
Salting: For recipes like fried green tomatoes, salting the tomato slices and allowing them to drain can help draw out some of the bitter compounds and moisture, though it does not eliminate all of the alkaloids.

Comparison of Toxin Reduction Methods


Method	Effectiveness for Reducing Tomatine/Solanine	Best Application	Considerations
Full Ripening	Most Effective	Harvesting vine-ripened tomatoes or ripening mature green ones indoors.	Takes time; best for fruits with good color showing.
High-Heat Frying	Moderately Effective	Preparing fried green tomatoes or using in cooked sauces.	Requires high temperatures; oil should not be reused.
Boiling	Minimally Effective	Not recommended as a primary method for toxin reduction.	Solanine is not water-soluble, so it is not leached out effectively.
Salting/Brining	Low Effectiveness	Used as a prep step for frying; primarily removes water and some surface bitterness.	Does not eliminate the bulk of the toxin.

Safe Consumption Practices

For the average person, consuming small amounts of unripe green tomatoes (such as in a chutney or relish) is unlikely to cause serious harm, as the body can process the low levels of alkaloids. However, the risk increases with the quantity and how unripe the fruit is. Here are some safe practices:

Discard damaged parts: Avoid eating any bruised, rotting, or visibly damaged tomatoes.
Avoid plant stems and leaves: Never consume the stems or leaves of the tomato plant, as these contain the highest concentrations of glycoalkaloids.
Use mature green tomatoes: When using green tomatoes for cooking, only use ones that have reached their full size, which have a lower alkaloid content than very small, immature ones. If they are very hard and bitter, avoid them.
Listen to your body: If you notice a lingering bitter taste or any gastrointestinal symptoms after eating, stop consumption.

Conclusion

While the prospect of solanine-like toxins in tomatoes can be concerning, the risks are easily managed with proper knowledge and preparation. The single most effective way to address the issue is by ensuring the tomato is fully ripened, as the natural process significantly reduces the tomatine levels. For those who enjoy culinary traditions like fried green tomatoes, high-heat cooking and moderation are key to a safe and enjoyable meal. By focusing on smart gardening, careful selection, and appropriate preparation, you can confidently and safely enjoy your tomato harvest without worry.

Visit Banner Health for additional information on nightshade vegetables

Frequently Asked Questions

No, cooking does not completely eliminate glycoalkaloids like solanine or tomatine. Boiling is largely ineffective, as the compounds are not water-soluble, while high-heat frying can only partially reduce them.

Yes, it is generally safe to eat fried green tomatoes in moderation. The high heat used in deep-frying helps to degrade some of the toxins, and the amount of alkaloids in a mature green tomato is relatively low to begin with.

To ripen green tomatoes indoors, place them in a paper bag or a box with a ripe banana or apple. The ethylene gas released by the ripe fruit will help accelerate the ripening process.

Symptoms of glycoalkaloid poisoning from unripe tomatoes are similar to solanine poisoning and can include nausea, vomiting, abdominal pain, diarrhea, headache, and a burning sensation in the mouth.

The highest concentrations of glycoalkaloids like tomatine are found in the leaves, stems, and immature green parts of the tomato plant, not in the ripe fruit.

A mature green tomato that has reached its full size and has a slight give when squeezed is safer to eat than a small, hard, immature one. Avoid any that taste notably bitter.

No, freezing does not reduce the solanine or tomatine content in tomatoes. The toxins are stable at freezing temperatures and will not be destroyed.