Why are Tomatoes Different Colours?
Tomatoes come in a variety of colours due to differences in their genetic makeup, which affects the pigments they produce. Each colour variation brings its own unique set of flavours, textures, and nutritional benefits. Here’s why tomatoes can be different colours:
1. Pigments in Tomatoes
The colour of a tomato is determined mainly by the presence of different pigments, which include:
Lycopene: This red pigment is the most common and gives many tomatoes their classic red colour. Lycopene is also a powerful antioxidant.
Beta-Carotene: This pigment appears orange and is a precursor to vitamin A. It is responsible for orange hues in some tomato varieties.
Chlorophyll: This green pigment is present when tomatoes are unripe. Some varieties, like green tomatoes, retain this colour even when ripe.
Anthocyanins: These pigments give a blue, purple, or blackish colour to certain tomato varieties. They are also found in blueberries and provide antioxidant benefits.
Carotenoids (such as lutein and zeaxanthin): These contribute to yellow colouring and are also beneficial for eye health.
2. Genetic Variations
Different tomato varieties have genetic traits that affect which pigments they produce and in what quantities. Breeders have selected these traits over time to create new types of tomatoes with specific colours, flavours, and uses.
For example, traditional red tomatoes have been bred to produce high levels of lycopene, while yellow and orange varieties have more beta-carotene and less lycopene.
Purple and black tomatoes are often hybrids that express both anthocyanins and lycopene, giving them a darker, richer colour.
3. Ripening Process
During the ripening process, tomatoes change colour as chlorophyll breaks down and other pigments become more prominent. For example, green tomatoes will turn red, yellow, or orange as they ripen.
However, not all tomatoes ripen to the same colour. Some varieties, like ‘Green Zebra,’ remain green even when ripe because of specific genetic traits that keep chlorophyll levels high.
4. Environmental Factors
The environment in which tomatoes are grown can also influence their colour:
Sunlight exposure can enhance the production of certain pigments, especially anthocyanins. That’s why purple tomatoes often develop their darkest hues on the side exposed to the sun.
Temperature plays a role too. Cooler temperatures can reduce the production of lycopene, leading to lighter or uneven coloring.
Soil composition and nutrition can affect the plant's health and pigment development, potentially altering the tomato’s colour.
5. Breeding and Hybrid Varieties
Over the years, farmers and scientists have created many hybrid tomato varieties to emphasize different colours, flavours, and textures. Some are bred for novelty, like blue or purple tomatoes, while others are selected for their taste and appeal, such as deep orange or bright yellow cherry tomatoes.
Heirloom tomatoes, which are often multicolored, have been preserved for their unique colours and flavours that differ from commercial red varieties.
6. Examples of Different-Coloured Tomatoes
Red Tomatoes: Classic varieties like ‘Roma’ and ‘Beefsteak,’ rich in lycopene.
Yellow/Orange Tomatoes: Varieties like ‘Sun Gold’ and ‘Yellow Pear,’ sweeter and lower in acidity.
Green Tomatoes: Varieties like ‘Green Zebra,’ tangy with a unique flavour profile.
Purple/Black Tomatoes: Varieties like ‘Black Krim’ and ‘Cherokee Purple,’ with a smoky, rich flavour due to anthocyanins.
White Tomatoes: Varieties like ‘White Beauty,’ which are milder and low in acidity.
Conclusion:
Tomatoes come in a spectrum of colours because of differences in genetic traits, pigments, environmental factors, and selective breeding. Each colour can offer a unique set of flavours and nutritional benefits, making tomatoes a versatile and diverse food crop. Whether it’s the classic red or a striking purple, these colours are a result of a fascinating mix of biology and cultivation.
