Volatile components of green walnut husks.

Volatiles were isolated from whole green mature walnuts (Hartley variety) with husks still intact using dynamic headspace sweeping with trapping on Tenax. A total of 45 volatile compounds were identified by GC-MS. Major volatiles identified included (E)-4, 8-dimethyl-1,3,7-nonatriene, pinocarvone, pinocarveol, myrtenal, myrtenol, (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene, caryophyllene epoxide, verbenol, verbenone, and terpinolene. Green walnuts that had been infested with codling moth showed appreciably higher amounts emitted for (E)-4,8-dimethyl-1,3,7-nonatriene, (E, E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene, alpha- and beta-pinenes, sabinene, (E)-beta-ocimene, (E,E)-alpha-farnesene, and linalool. The infested nuts also emitted benzyl methyl ether, isobutyl cyanide, and 1-nitro-3-methylbutane, compounds not found with the healthy nuts. Volatiles from uninfested green walnuts at the maturity stage where the husk was just beginning to split were also analyzed and compared.