Production of β-damascenone precursors in cell cultures of Vitis labruscana cv Concord grapes.

Callus cultures of Vitis labruscana cv. Concord were initiated from both immature fruit and petiole tissue. Analysis revealed that the acid hydrolyzable precursors to β-damascenone, a compound important to the flavor of most grape species, were present in both callus types. Light and increased sucrose concentration were shown to raise the levels of the precursor, some of which are glycosides, in the petiole callus but not in the fruit callus. Addition of β-carotene, a biogenic precursor to β-damascenone and its precursors and the addition of amitrole, an inhibitor of carotenoid cyclization and production, had no effect upon precursor levels in either tissue. Aroma compounds specific to V. labruscana grapes and other American species of grapes were not found in the callus tissue. Cell suspensions were initiated from the fruit callus and analyzed for the American character compounds as well as β-damascenone and its acid hydrolyzable precursors. Once again, no aroma compounds specific to American species were found while β-damascenone precursors were present at levels lower than were found in callus on solid media and only during stationary phase of growth.