Source : Webster's Revised Unabridged Dictionary (1913)

Acidify \A*cid"i*fy\, v. t. [imp. & p. p. {Acidified}; p. pr. &
   vb. n. {Acidifying}.] [L. acidus sour, acid + -fy: cf. F.
   acidifier.]
   1. To make acid; to convert into an acid; as, to acidify
      sugar.

   2. To sour; to imbitter.

            His thin existence all acidified into rage.
                                                  --Carlyle.

Source : WordNet®

acidify
     v 1: make sour or more sour [syn: {sour}, {acidulate}, {acetify}]
          [ant: {sweeten}]
     2: turn acidic; "the solution acetified" [syn: {acetify}] [ant:
         {alkalize}]
     [also: {acidified}]

acidified
     See {acidify}