Abstract
Increasing light exposure to grape bunches has long been shown to influence the amount of phenolics in the fruit at harvest. In cool climates, increasing exposure is a particularly common practice due to the added benefit of allowing better disease control. For sparkling wines, phenolic composition is as important as the quantity, however little is known about the effect of increased bunch exposure on the phenolic profiles of the juice and wine. In this study, mature and lateral leaves were removed, up to and including the 4th node, at three different times in the 2011 and 2012 seasons (pre-flowering, pea sized berries and 50 % veraison) in Northern Tasmania with Pinot Noir and Chardonnay. Fruit composition parameters were measured and the phenolic profiles of base wines were analysed by spectral fingerprinting. Base wines were produced using standard protocol small scale winemaking (12 kg ferments). The phenolic fingerprint of base wines showed that strongest and most consistent separation by Principal Component Analysis (PCA) was between the pre-flowering leaf removal treatment and the control. This is despite a lack of difference in fruit quality or yield reduction. Spectra from caffeic and ferulic acid were compared, and with similar loadings at around 260, 310 and 330 nm, it can be postulated that hydroxycinnamates are driving the differences between these treatments.
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Claims 3
Claim · model-written summary
Pre-flowering leaf removal gave the strongest and most consistent PCA separation of base-wine phenolic fingerprints from the control in grape (Pinot Noir and Chardonnay) in Northern Tasmania.
- Taxon
- grapee0
- Material
- Pinot Noir and Chardonnaye1
- Treatment
- pre-flowering leaf removale2
- Outcome
- strongest and most consistent separation by Principal Component Analysis (PCA)e2
- Comparator
- controle2
- Setting
- Northern Tasmaniae1
Not reportedDirection
Verbatim
e0“Increasing light exposure to grape bunches”
e1“In this study, mature and lateral leaves were removed, up to and including the 4th node, at three different times in the 2011 and 2012 seasons (pre-flowering, pea sized berries and 50 % veraison) in Northern Tasmania with Pinot Noir and Chardonnay”
e2“The phenolic fingerprint of base wines showed that strongest and most consistent separation by Principal Component Analysis (PCA) was between the pre-flowering leaf removal treatment and the control”
Claim · model-written summary
Leaf removal caused no difference in fruit quality or yield reduction compared with the control in grape (Pinot Noir and Chardonnay).
Verbatim
e0“Increasing light exposure to grape bunches”
e2“The phenolic fingerprint of base wines showed that strongest and most consistent separation by Principal Component Analysis (PCA) was between the pre-flowering leaf removal treatment and the control”
e3“This is despite a lack of difference in fruit quality or yield reduction”
Claim · model-written summary
Hydroxycinnamates are postulated to drive the differences in base-wine phenolic profiles between the leaf removal treatments in grape.
Verbatim
e0“Increasing light exposure to grape bunches”
e4“it can be postulated that hydroxycinnamates are driving the differences between these treatments”
The same questions in other papers
pruning · quality: grain · VitisPositive and negative results
3 papers in the same direction as this paper · 1 in the opposite direction
- positive
- no effect
- no effect
1 paper more in this group
See all 5 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.