Exploring the possible translocation of smoke-derived volatile phenols from grapevine leaves to fruit

Speculation remains regarding the possible translocation of smoke-derived volatile phenols (VPs) from grapevine leaves to fruit. This study exploited the sorptive properties of activated carbon fibre (ACF) cloth to resolve ambiguity around VP translocation. Smoke-derived VPs and their glycosides accumulated in leaves following grapevine smoke exposure (at up to ∼1700 and 2400 μg/kg, respectively), but where grapes were enclosed in ACF cloth to prevent smoke contamination, appreciable quantities of free or glycosylated VPs were not observed, providing no evidence of translocation. Elevated grape guaiacol and guaiacol glycosides were also detected following exposure of potted microvines and excised table grapes to airborne guaiacol, even when bunches were enclosed in plastic. The absence of appreciable quantities of free or glycosylated guaiacol in bunches that were enclosed in ACF cloth, also argues against translocation occurring. Results from previous studies should be interpreted carefully given airborne volatiles clearly permeate soft plastics.