bunch exposure effects on the quality of pinot noir and

BUNCH EXPOSURE EFFECTS ON THE QUALITY OF PINOT NOIR AND
CHARDONNAY FRUIT AND BASE WINES FOR COOL CLIMATE
SPARKLING WINE PRODUCTION
EFFETS DE L’EXPOSITION DES GRAPPES SUR LA QUALITE DU FRUIT DE PINOT NOIR ET
CHARDONNAY, ET DE LEUR VIN DE BASE POUR LA PRODUCTION DE VIN MOUSSEUX DANS
UN CONTEXTE CLIMATIQUE DOUX
Fiona L. Kerslake, Joanna E. Jones1, Robert G. Dambergs1,2 and Dugald C. Close1
1 Tasmanian Institute of Agriculture, Perennial Horticulture Centre, University of Tasmania, . Launceston,
Tasmania. 2The Australian Wine Research Institute, Tasmanian Institute of Agriculture, Hobart, Tasmania
Introduction
Removing leaves is common practice for table wine production, but less is known about the impact on grapes destined for sparkling wine production. Of
particular importance is the increased exposure of bunches and leaves to Ultra-Violet radiation as this stimulates the accumulation of UV absorbing
compounds as part of the plants defence mechanism. The main groups of UV absorbing compounds are flavonols and hydroxycinnamic acids, compounds
important to the mouthfeel and texture of sparkling wines.
Materials and methods
- 2010/2011 Northern Tasmania (NTas) and Southern Tasmania
(STas) vineyards, D5V12 Pinot Noir and I10V1 Chardonnay
- Pre-flowering, pea sized berries, 50 % veraison leaf removal (LR)
and no leaf removal (control)
- Standard protocol small scale winemaking
- Principal component analysis (PCA) of UV spectra of base wines
Results
-
Table I. Yield, yield components and fruit composition for 2011 Chardonnay and Pinot Noir in response to
leaf removal treatments at three different timings throughout the growing season.
Table I. Rendement, composantes du rendement et qualité du raisin de Chardonnay et Pinot noir pour des
effeuillages à trois stades de croissance différents en 2011.
PrePea-size
Control
Veraison Significance
flowering berries
TSS (°Be)
9.8
9.9
9.7
9.7
ns
pH (no units)
3.01 b
2.91 a
2.96 ab
2.95 ab
*
NTas
TA (g/L)
14.85
15.3
14.84
15.08
ns
Grape total phenolics (AU/g)
0.63 c
0.50 a
0.57 b
0.47 a
**
Chardonnay
TSS (°Be)
9.8 a
9.9 ab
10.1 b
10.0 b
*
pH (no units)
3.20
3.04
3.10
3.05
ns
STas
TA (g/L)
12.58 a
14.69 b
13.45 a
13.36 a
*
Grape total phenolics (AU/g)
0.60 ab
0.74 c
0.59 a
0.68 bc
**
TSS (°Be)
9.3
9.8
8.8
9.3
ns
pH (no units)
2.97
2.93
2.93
2.94
ns
TA (g/L)
14.83
15
13.04
15.43
ns
NTas
Grape total anthocyanins (AU/g)
0.39 a
0.59 b
0.32 a
0.40 a
**
Chardonnay
- No yield composition effects
- Site effect on fruit composition (Table I)
- NTas – pH and phenolics affected
Pinot Noir
- STas – TSS, TA and phenolics affected
- Similar effect at both sites on base wine UV spectra (Figure 1)
- Pre-flowering and control base wines had the most different
UV spectra from each other with strong loadings at 260, 310 and 330 nm,
Indicative of an effect of low molecular weight hydroxycinnamates
- Pinot Noir
- Early LR decreased berry weight at NTas
- Site effect on fruit composition (Table I)
- NTas - Anthocyanins affected
- STas – TA and anthocyanins affected
- Site effect on base wine UV spectra
- NTas = similar effect as Chardonnay (strong loadings at 260, 310
and 330 nm, indicative of an effect of low molecular weight hydroxycinnamates)
- STas = little effect
STas
Grape total phenolics (AU/g)
TSS (°Be)
pH (no units)
TA (g/L)
1.05
10.3
2.99
11.98 a
1.22
9.8
2.92
13.26 b
1
10.1
2.96
13.28 b
1.08
10
2.93
13.77 b
ns
ns
ns
*
Grape total anthocyanins (AU/g)
0.53 b
0.40 a
0.44 ab
0.44 a
*
Grape total phenolics (AU/g)
0.86
0.84
0.86
0.88
ns
(a)
Discussion and Conclusion
•
The wavelengths responsible for driving the
separation of the base wines (260, 310 and 330 nm)
suggest that pre-flowering leaf removal affects
hydroxycinnamate concentrations in the base wines.
•
The lack of large differences in yield or fruit
composition for these two varieties suggest that fruit
exposure is driving the hydroxycinnamate response, which
References
are critical compounds for mouthfeel and texture of
sparkling wines.
Acknowledgements
This work was supported by an industry consortium through an AusIndustry,
Industry Co-operative Innovation Program. TIA is home to the AWRI’s
Tasmanian Node, which is jointly funded by TIA, UTAS, AWRI and the
GWRDC.
(b)
(c)
Figure 1: Principal component analysis of UV spectra (230-450 nm) of base wines made from 2011 Northern
Tasmania Chardonnay leaf removal trials; (a) PCA scores plot labelled by treatment (cont = control, pea = peasized berry leaf removal, ver = veraison leaf removal, pre-fl = pre-flowering leaf removal); (b) PC-1 loadings versus
wavelength (230-450 nm) ; (c) PC-2 loadings versus wavelength (230-450 nm).
Figure 1 : Analyse en composantes principales du spectre UV (230 - 450 nm) des vins de base issus de l’essai
Chardonnay, nord de la Tasmanie, 2011. (a) Scores factoriels des individus, nommés par leur traitement (cont =
témoin, pea = effeuillage au stade « petit pois », ver = effeuillage au stade véraison, pre-fl = effeuillage au stade préfloraison) ; (b) Poids factoriels sur la première composante selon la longueur d'onde (230 - 450 nm) ; (c) Poids
factoriels sur la deuxième composante selon la longueur d’onde (230 – 450 nm).