Book 29, Question 40
Why do green tomatoes turn red?
A green tomato is full of chlorophyll, the green pigment.
As the fruit ripens, the plant breaks down the chlorophyll and builds a red pigment called lycopene. Yellow and orange pigments show up along the way, which is why a ripening tomato can look streaky. The fruit also turns softer and sweeter. A ripe tomato tastes best when it is picked fully colored.