Effect of the timing of leaf removal on the green and fruity aromas and flavours of (Vitus vinifera L. Cv.) Pinot noir wine

Abstract

Mechanical leaf removal was applied to Pinot noir vines in a com-mercial vineyard in Waipara, New Zealand, in the 2007–2008 and 2008–2009 growing seasons. Fruit-zone treatments consisted of no leaf removal (control), leaf removal from the fruiting zone 7 days after flowering, leaf removal from the fruiting zone 30 days after flowering, and leaf removal at 5% berry color change (by visual assessment). Headspace-solid phase microextraction-gas chromatography-mass spectrometry-stable isotope dilution analysis (HS-SPME-GC-MS-SIDA) was used to analyze 14 “green” and “fruity” volatile aroma compounds in Pinot noir wines. The fruity ethyl esters showed no discernible pattern between treatments but a difference between years was observed. Green C6 aroma compounds and fruity C13-norisoprenoids increased in all wines in 2009. Sensory analysis by Waipara winemakers by modified free-choice profiling found that wines from non-defoliated vines were described as having a rhubarb and lees autolysis aroma but were vegetal and candied on the palate. Wines from defoliated vines had elevated dark fruit aroma and more dark fruit, tannin, and weight on the palate. Fruity aroma compounds were found to be above their odor threshold levels in all wines but green aroma compounds were below. Free-choice profiling proved to be a useful sensory analysis method that did not require panelist training and allowed experts to describe wines using their own terminology