What is "bletting"

Blet \Blet\, v. i. [imp. & p. p. Bletted; p. pr. & vb. n. Bletting.] To decay internally when overripe; -- said of fruit.

Bletting \Blet"ting\, n. A form of decay seen in fleshy, overripe fruit.
--Lindley.

n. A fermentation process in certain fruit beyond ripening. vb. (present participle of blet English)

Bletting is a process of softening that certain fleshy fruits undergo, beyond ripening. There are some fruits that are either sweeter after some bletting, such as sea buckthorn, or for which most varieties can be eaten raw only after bletting, such as medlars, persimmons, quince, service tree fruit, and wild service tree fruit ("chequers"). The rowan or mountain ash fruit must be bletted and cooked to be edible, to break down the toxic parasorbic acid (hexenollactone) into sorbic acid.