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Microsoft PowerPoint poster WAC 2017 Salmon et al. v230317 .pdf


Nom original: Microsoft PowerPoint - poster WAC 2017 Salmon et al._v230317.pdf
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Effect of grape juice press fractioning and Botrytis berry
infection on proteolytic activity of Champagne base wines
Thomas Salmona, Duc An Hoanga, Céline Vrigneaub, Richard Marchala, Sandrine Jégoua,*
a Laboratoire

d’Oenologie et Chimie Appliquée, URVVC EA 4707, Université de Reims Champagne-Ardenne, France
b Institut Œnologique de Champagne, Route de Cumières, Epernay, France
*sandrine.jegou@univ-reims.fr

INTRODUCTION

MATERIALS AND METHODS

The press fractioning is an important step in the production of sparkling base wines to segregate the
grape juices with different qualities[1, 2, 3]. A complete pressing cycle results in a large variation in juice
composition[3,4]. Particularly the protein contents of grape juices and Champagne base wines produced
from Pinot meunier (PM) press fractions exhibited strong quantitative and qualitative differences[3]. These
could be partially explained by proteolytic activities arisen from the grape berry, fermentative yeast, or a
grape fungus infection. With regards to wine quality, the protease activity could impact the protein
fraction implicated in foaming properties, white wine haze formation, and potential nitrogenous source
for yeast alcoholic fermentation. The aim of this study was to better understand the protease activity
change due to grape juice fractioning during the pressing cycle at industrial and laboratory scales,
according to the presence or absence of rotten bunches, and their impact on protein content.

Grape juices and Champagne base wines. Six Pinot meunier (PM 2013) grape juice fractions were
collected during the pressing cycle from a 8000 kg pneumatic press. Juices were collected at the
beginning and the end of autopressing (APb and APe), and at the middle of each squeeze S from S1 to
S4 (Figure 1). Five healthy (H) or botrytized (B) Chardonnay (CH 2014) grape juice fractions were
collected from a 6 kg laboratory press (squeeze from S1 to S5). The grape juice fractions were vinified
separately at 18 °C (S. cerevisiae var. bayanus). After alcoholic fermentation, the wines were
centrifuged and stored at 11 °C then 4 °C before filtration.
Gluconic acid content. The gluconic acid (GA) content (mg/L) of the grape juices and base wines was
determined using a UV-visible Hitachi 911 sequential analyzer (Roche Diagnostics, France) according
to the analytical method recommended by the Compendium of International Methods of Wine and
Must Analysis (O.I.V., France).
Protein concentration. The wine protein content was determined according to the Bradford method.
Proteolytic activities. The wine proteolytic activity was assayed against Bovine Serum Albumine (BSA)
and followed by protein degradation by SDS-PAGE after gel Coomassie Blue staining.

1600
1400

Pressure (millibars)

1200
1000
S4

800
S1

600

S2

S5

S3

400
200
APe

0
0

20

40

60

80
100
120
Time (minutes)

140

160

180

Table 1. Gluconic acid content of PM
2013, and healthy and botrytized CH
2014 grape juices and base wines

200

Figure 1. Diagram of pressing cycle and Pinot
meunier 2013 grape juice fractions collected
during the press fractioning

PM 2013

RESULTS AND DISCUSSION
Gluconic acid content of grape juices and base wines. The GA is an index marker for the presence of Botrytis cinerea. In Table 1, the values of the PM 2013 and healthy
CH 2014 grape juices and wines from S1 to S4 or S5 show the low level of grape berry contamination by Botrytis cinerea. Indeed, the GA concentration is adequate since
it is equal to, or lower than 100 mg/L. In contrast, the GA high level of PM 2013 auto-pressed juices and wines APb and APe corresponds to a largest presence of Botrytis
cinerea on the berry skin drained from the first juice extracted. After rinsing of the grape skins, a strong decrease of the GA content is observed for PM 2013 grape juice
S1 (79 mg/L). The GA content of botrytized CH 2014 juices and wines is from 6 to 140 times higher than content of healthy CH 2014 juices and wines according to
squeeze. Moreover, the GA level decreases by around 66% in botrytized juices (from 407 mg/L to 139 mg/L) and 69% in botrytized wines (from 502 mg/L to 154 mg/L)
throughout the pressing cycle from the S1 to S5.

CH 2014
healthy botrytized

grape juice
APb
APe
S1
S2
S3
S4
S5

261
152
79
61
63
65
-

5
2
1
7
4

407
179
140
126
139

wine
APb
APe
S1
S2
S3
S4
S5

399
198
14
82
15
35
-

16
15
9
6
25

502
185
153
145
154

Protein concentration and proteolytic activity of Champagne base wines. Significant changes in protein content and proteolytic activity of PM 2013 and CH 2014 base
wines are observed during the pressing cycle at industrial and laboratory scales (Figures 2 and 3).
The specific proteolytic activity decreases by 32,5% between S1 and S4 for PM 2013 wines (by around 50% between APe and S4), and by 87,5% and 74% between S1 and
S5 for healthy and botrytized CH 2014 wines respectively. Moreover, the proteolytic activity observed in S1 is 1.25, 2.4 and 2.6 times higher than S2 for PM 2013, healthy
and botrytized CH 2014 wines respectively. The detected proteolytic activities are quite similar for the PM 2013 and healthy CH 2014 wines (kinetic time: 7 h) while they are higher in botrytized CH 2014 wines, from 35 to 110
fold according to squeeze (kinetic time: 7 min). The proteolytic activity of botrytized CH wines shows a positive correlation with gluconic acid content of grape juices (R2 = 0.995).
The protein concentration of the PM 2013 base wines decreases by 24% throughout the pressing cycle, from S1 to S4, as observed for wine proteolytic activity. A positive correlation is found between the proteolytic activity and
the protein content of PM 2013 wines (R2 = 0.903) during the pressing cycle. In contrast, the protein level increases by around 30% and 41% from S1 to S3 for healthy and botrytized CH 2014 wines respectively. At the end of
press fractioning, the CH wine protein concentrations decrease by 16%. Protein levels of botrytized CH 2014 wines are lower than those observed for healthy wines, from around 1.5 to 2 fold according to squeeze. The protein
content of botrytized CH wines shows a negative correlation with proteolytic activity (R2 = 0.765).

PM 2013

Healthy CH 2014

15
10
5

APb
0,008

APe

S1

S2

S3

S4

0,0074

0,006

0,0053

- 32,5%
0,0040

0,004

0,0032

0,0028

0,0027

0,002

28,1
25,6

24,1

25
20

23,4

19,6

15
10
5
0

APb

APe

S1

S2

S3

S4

Figure 2. Changes in protein content and proteolytic
activity of PM 2013 base wines elaborated from grape
juices collected during the press fractioning

30
25
20

17,1

15
10

15,6

13,1

14,4

10,1

5
0

S1H

S2H

S3H

S4H

S5H

S1B

0,008

S2B

S3B

S4B

S5B

0,077

0,087

S4B

S5B

0,4
0,0064

0,006

- 87,5%

0,004
0,0025

0,0022

0,0022

0,002
0,0008
0,000

0,000

Protein concentration (mg/L BSA eq)

18,3

35

30

Specific activity (U/mg total proteins)

22,1

Protein concentration (mg/L BSA eq)

20

23,1

Specific activity (U/mg total proteins)

26,5

25,6
25

Press fractioning at laboratory scale

Protein concentration (mg/L BSA eq)

35
29,1

30

0

Specific activity (U/mg total proteins)

Press fractioning at industrial scale

35

Botrytized CH 2014

0,334
0,3

- 74%

0,2
0,140
0,104
0,1

0
S1H

S2H

S3H

S4H

S5H

S1B

S2B

S3B

Figure 3. Changes in protein content and proteolytic activity of healthy and botrytized CH 2014 base
wines elaborated from grape juices collected during the press fractioning

CONCLUSION AND PERSPECTIVES
This study proves that the proteolytic activity in Champagne base wines is affected by press fractioning technique at industrial and laboratory scales and by Botrytis cinerea grape berry infection. The decrease of activity of
proteases in base wines is highlighted throughout the press fractioning for two presses, two grape varieties, two vintages and healthy/infected grapes. The grape, fungus and yeast protease activity could not especially explain
the protein content change. These could be impacted by the initial composition of the grape juice, the maturity stage or degradation of grape berry pulp and cell wall, and/or the protein solubility loss. Studies should be carried
out in order to better understand the possible relationship with foaming properties of Champagne sparkling wines.
[1] Marchal R., Ménissier R., Oluwa S., Bécart B., Jeandet P., Kemp B., Foss C., Robillard B. 2012. Macrowine 2012, Bordeaux , 18-21 juin 2012.
[2] Hardy G. 1990. Revue des Œnologues, 55, 17-25.
[3] Jégou S., Salmon T., Parmentier M., Rivero Granados F.J., Vrigneau C., Robillard B., Marcelo P., Vasserot Y., Marchal R. 2014. In Proceedings
of the 3rd International Conference Wine Active Compounds, WAC 2014, Beaune, France, R. Gougeon (ed), pp. 87-89.
[4] Jégou S., Hoang D.A., Salmon T., Williams P., Oluwa S., Vrigneau C., Doco T., Marchal R. 2017. Food Chemistry,
dx.doi.org/10.1016/j.foodchem.2017.03.032

Acknowledgements: The authors thank the Association Recherche Oenologie Champagne et Université
(Reims, France) for financial support. We gratefully thank the Champagne Bruno Paillard (Reims, France)
for providing Pinot meunier must samples.


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