Can I accelerate the ripening of strawberries?

Question

It's Xmas Eve and the only strawberries in the shops were not quite ripe. I've got guests tomorrow at lunch and I've got to ripen these overnight!

Strawberries are classically considered non-climacteric fruits so are not supposed to ripen once removed from the plant. But clearly the white parts of the berries do get redder after picking (1). And apparently ethylene is released by the fruit, and is involved in signalling pathways (2) so the situation is not as clear as was once thought.

So, am I wasting my time placing a banana and some kiwi fruit next to my nearly ripe strawberries, and covering them with paper to trap any ethylene, to see if I can at least hasten some parts of the ripening process overnight?

1. That's a Berry Good Question – Strawberry Ripening after Harvest?
2. Ethylene is involved in strawberry fruit ripening in an organ-specific manner.

Answer 1

You did exactly what I would have recommended. Very ripe bananas especially. I'd enclose them together with the strawberries in a paper bag, close it off with very little airspace, and keep it at at least 75 degrees.

Sometimes, however, the ripe part of a strawberry can overripen and begin to decay while part of that same fruit is still white. More common with pointed berries picked near the beginning of the ripening process. I doubt that'll happen in your case. There's only so much you can do. If you're serving them whole, you may have to pick out a couple just before, if they don't ripen fast enough.

Also, where it's white by the stem is not a sign of unripeness (like white on the pointy end is). It's a sign of poor internal coloring, common in berries bred for shipping more than fresh use.

Answer 2

You may induce some color change, and reduce the water content somewhat, which can make the flavor slightly sweeter, but strawberries, unlike most fruits, do NOT ripen after they are picked. They must be picked when they are fully ripe for best texture and flavor.