We
checked several of our gardening and food science books to no avail, although
we did learn from Lynn Coulter’s Gardening with Heirloom Seeds that tomatoes,
native to South America and members of the nightshade family, took a while to
catch on among Europeans.
However,
Brian McMahon at MentalFloss, Mandy Kendrick at Scientific American, and the
University of Cambridge’s IntoBiology website all had the answer to our question.
Chlorophyll makes the tomatoes green and, as they ripen, the chlorophyll begins
to dissolve. Lycopene, a chemical in the tomato that has a red color, shows
through as the chlorophyll dissolves. As this happens, the tomato will also
become sweeter, softer, less acidic, and ready to eat.
Fruits
produce a chemical called ethylene in certain conditions, including as they
ripen, and other fruit will respond to it. According to Jeremy Dore at GrowVeg
and McMahon at Mental Floss, a green tomato in a paper bag with a ripe banana
will respond to the ethylene given off by the banana, and it will begin to
ripen itself.
