By Harold McGee
There are two different styles of ripening among fruits. One is dramatic. When triggered by ethylene, the fruit stimulates itself by producing more ethylene, and begins to respire—to use up oxygen and produce carbon dioxide—from two to five times faster than before. Its flavor, texture, and color change rapidly, and afterwards they often decline rapidly as well. Such “climacteric” fruits can be harvested while mature but still green, and will ripen well on their own, especially if nudged by an artificial dose of ethylene. They often store their sugars in the form of starch, which enzymes convert back into sweetness during the post-harvest ripening.