ablandarse

v. soften, make soft; mellow, become soft; relent, become less severe; mitigate, soften in force or severity

= soften, tenderise [tenderize, -USA].
Ex: This was so that the stuffing could be teased out and cleared of lumps, and so that the pelts could be softened by currying and soaking them in urine; the smell is said to have been revolting.
Ex: Brief details are given of a method for hanging mutton and lamb carcasses by the pubis to tenderise the meat.