Do Tomatoes Contain Chlorophyll?: A Deep Dive into Ripening and Nutrition Diet

October 1, 2025 •

3 min read

As many gardeners know, all immature tomatoes are initially green, a color that comes from high concentrations of chlorophyll. This essential pigment plays a crucial role in the plant's development before it gives way to the vibrant colors and distinctive nutritional profile of a ripe fruit.

Quick Summary

Immature, green tomatoes are filled with the pigment chlorophyll, which is vital for photosynthesis. As they ripen, chlorophyll breaks down and red carotenoids like lycopene are produced. Some varieties are genetically bred to remain green, resulting in different flavor and nutritional profiles.

Key Points

Initial Green Color: All tomatoes contain chlorophyll in their unripe, green stage to perform photosynthesis, which aids in fruit development and sugar production.
Ripening Transformation: During ripening, the fruit's chloroplasts transform into chromoplasts, causing the green chlorophyll to break down and degrade.
Lycopene's Appearance: The red color of a ripe tomato is due to the synthesis of lycopene, a powerful antioxidant that replaces the degraded chlorophyll.
Genetically Green Varieties: Some "true" green tomato varieties, like 'Green Zebra', possess a genetic trait that actively blocks lycopene formation, causing them to retain their chlorophyll and stay green even when ripe.
Nutritional Differences: While ripe red tomatoes are rich in lycopene and vitamin C, unripe green tomatoes contain the alkaloid α-tomatine, and their flavor is more acidic.
Factors Affecting Ripening: Temperature and sunlight significantly influence the ripening process. Extreme temperatures can inhibit lycopene production, while natural plant hormones like ethylene promote ripening.

The question, "Do tomatoes contain chlorophyll?" has a simple answer: yes, they do, but only during certain stages of their life cycle. The journey of a tomato, from its initial green color to a vibrant red, yellow, or even purple hue, is a fascinating process of natural pigment change. This change fundamentally alters the fruit's nutritional composition and flavor, making a distinction between green and red tomatoes important for anyone interested in healthy eating.

The Role of Chlorophyll in Green Tomatoes

Chlorophyll is the green pigment found in plant cells, essential for photosynthesis where light energy is converted to chemical energy. In developing tomatoes, this contributes to carbon assimilation, impacting sugar content and yield. During the green stage, the fruit performs photosynthesis, aiding growth and sugar development. Immature tomatoes have high chlorophyll concentrations, resulting in their pronounced green color, which fades as ripening begins.

The Chemical Shift: From Green to Red

Ripening is a biochemical process initiated by ethylene. Chloroplasts containing chlorophyll transform into chromoplasts, which synthesize and store other pigments, mainly carotenoids.

The Rise of Carotenoids

As chlorophyll disappears, carotenoids like lycopene become prominent, giving ripe tomatoes their red, yellow, or orange colors. Lycopene, a powerful antioxidant, is abundant in red tomatoes and increases significantly during ripening. Other carotenoids like beta-carotene are also present in various tomato varieties.

Nutritional Changes During Ripening

Chlorophyll degradation and carotenoid synthesis significantly alter a tomato's nutritional value. Unripe green tomatoes contain α-tomatine, an alkaloid that decreases during ripening. Ripe red tomatoes are rich in lycopene, vitamins A and C, offering various health benefits.

Not All Green Tomatoes are Unripe

Some tomato varieties remain green when ripe due to a genetic trait that prevents lycopene formation, maintaining their chlorophyll. Examples include 'Green Zebra' and 'Aunt Ruby's German Green', known for their tangy or spicy flavor profiles. This "stay-green" characteristic is often linked to mutations affecting chlorophyll breakdown during ripening.

The Influence of Environmental Factors on Ripening

Ripening is affected by temperature and sunlight. Optimal temperatures are needed, as excessive heat can hinder lycopene production, causing uneven ripening. Similarly, low temperatures can slow down ripening. Sunlight is vital for both photosynthesis and pigment development during ripening.

Comparison of Chlorophyll and Lycopene in Tomatoes


Feature	Chlorophyll (Unripe Tomato)	Lycopene (Ripe Tomato)
Primary Function	Photosynthesis, energy conversion for growth.	Antioxidant, responsible for red color.
Nutritional Profile	Contains some nutrients, but also higher levels of α-tomatine.	Excellent source of antioxidants, vitamins A and C.
Associated Color	Green.	Red.
Flavor Profile	Often firm, acidic, and lacks sweetness.	Soft, juicy, and sweet.
Prevalence	Dominant in all immature fruit.	Dominant in mature, ripe fruit, especially red varieties.

Conclusion: The Spectrum of Tomato Nutrition

Whether a tomato contains chlorophyll depends on its maturity and variety. Unripe tomatoes have chlorophyll, while ripe ones replace it with carotenoids like lycopene. For most red tomatoes, ripening brings significant nutritional changes. Ripe green varieties offer a distinct flavor and nutrient profile. Enjoying diverse tomato types provides a range of vitamins, antioxidants, and flavors.

For more detailed scientific information on fruit ripening and chlorophyll breakdown, resources like those from the National Institutes of Health can be consulted.

Frequently Asked Questions

Unripe green tomatoes contain small amounts of the alkaloid tomatine, which can be toxic in large quantities. However, the amount is too low to be harmful to most people. True green tomato varieties that are ripe are perfectly safe to eat.

An unripe green tomato is immature and firm, with a high chlorophyll content and an acidic taste. A ripe green tomato is a specific variety that is genetically designed to stay green when mature, but it will soften and develop a tangy flavor.

Ripe red tomatoes have significantly higher levels of the antioxidant lycopene compared to green ones. As a tomato ripens, the lycopene is synthesized and replaces the chlorophyll.

During ripening, the tomato undergoes a cellular change where chloroplasts, which contain chlorophyll, are converted into chromoplasts. This process causes chlorophyll to break down while red carotenoids like lycopene are produced and stored.

Yes, green tomatoes that have reached a mature size can ripen off the vine, especially if placed in a paper bag with a ripe fruit like a banana. The ethylene gas released by the ripe fruit helps trigger the ripening process.

Green tomatoes contain some nutrients and fiber, but their phytochemical profile is different from ripe red tomatoes. Some research suggests links between chlorophyll and higher sugar content in the final fruit, but the primary nutritional benefits typically lauded are from the antioxidants in ripe tomatoes.

A phenomenon called 'green shoulder' can occur when a tomato ripens unevenly. This is often due to genetic factors or environmental stress like heat, which can inhibit lycopene production in certain parts of the fruit.