Yes, MATURATION is a Scrabble word!

Letter values in Scrabble US: M 3, A 1, T 1, U 1, R 1, A 1, T 1, I 1, O 1, N 1.

Is it a valid word?

MATURATION is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

coming to full development; becoming mature
(biology) the process of an individual organism growing organically; a purely biological unfolding of events involved in an organism changing gradually from a simple to a more complex level
(medicine) the formation of morbific matter in an abscess or a vesicle and the discharge of pus

Not playable in Scrabble US: MATUREMENT.