to ripen fruit, or bake, cook something (see Molina)
Alonso de Molina:
icuci. (pret. oicucic.) madurarse la fruta, o cocerse algo. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 34r. col. 1. Thanks to Joe Campbell for providing the transcription.