Free and glycosylated green leaf volatiles, lipoxygenase and alcohol dehydrogenase in defoliated Nebbiolo grapes during postharvest dehydration

Background and Aims Nebbiolo grapes are used to produce Sfursat wine, following partial dehydration. This research aimed clarify the influence of fruit exposure light postharvest water loss on concentration green leaf volatiles (GLVs) lipoxygenase (LOX) alcohol dehydrogenase (ADH) activity grapes. Methods Results from Control vines (no defoliation) (ND) defoliated at fruitset (DFS) or post-veraison (DPV) were harvested about 23°Brix dehydrated 10 20°C, 60% RH air flow 1.5 m/s. Berries sampled 20% mass (ML). Significant differences in crop yield, bunch berry observed. As expected, higher dehydration temperature, faster process: ML 20°C occurred between 18 25 days, shortest time corresponding ND longest DFS; 10°C, lasted 27 32 days. At ADH was almost double that DFS much than other samples. harvest, LOX did not show any difference among samples, while 10°C 10% ML, enzyme increased significantly then declined especially total free GLVs associated with metabolism lipid oxidation 9434, 7212 11 656 ?g/kg dry weight (DW) ND, DPV respectively; bound lipid-derived 7599, 486 15 409 DW respectively. During induced + activity, but GLVs, produced by defoliation, greatly decreased. Conclusions Defoliation affected response temperature: cold stress (10°C) glycosylation formation (via ADH) membrane LOX); a further effect observed removal, regardless application. Significance Study The timing defoliation temperature significant factors mitigate