The Collaborative International Dictionary of English v.0.48:

Scranch \Scranch\, v. t. [imp. & p. p. Scranched; p. pr. & vb.
   n. Scranching.] [Cf. D. schransen to eat greedily, G.
   schranzen. Cf. Crunch, Scrunch.]
   To grind with the teeth, and with a crackling sound; to
   craunch. [Prov. Eng. & Colloq. U. S.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

scranch
    v 1: make a crushing noise; "his shoes were crunching on the
         gravel" [syn: crunch, scranch, scraunch, crackle]