1. EVOLUTION OF PHENOLIC COMPOUNDS DURING WINEMAKING AND MATURATION UNDER MODIFIED ATMOSPHERE
A. Bimpilas, D. Tsimogiannis, V. Oreopoulou
Laboratory of Food Chemistry and Technology, School of Chemical Engineering, National Technical University of Athens (NTUA)

2. Phenolic substances of wine
Phenolic acids
Gallic
Caffeic
P-coumaric
Flavan-3-ols
Catechin
Epicatechin
Procyanidins
Flavonols
Quercetin
Kaempferol
Myricetin
Anthocyanidins
Malvidin
Delphinidin
Cyanidin
Petounidin
Peonidin

3. Anthocyanins
3-Ο-glucoside
3-Ο-(6-acylated)-glucoside

4. Reactions between phenolic compounds during storage
Anthocyanins
Flavanols
Polymeric pigments
Flavanol-Anthocyanin adduct
Methylmethine Flavanol-Anthocyanin adduct
Anthocyanin
Anthocyanin-Flavanol adduct
Flavanol

5. Use of inert gases during storage
Wine is protected from oxidative spoilage
The initial good quality (fruit bouquet, color and flavor) is ensured
Phenolic compounds of wine are protected

6. Experimental

7. Alcoholic fermentation
Vinifications
Alcoholic fermentation
Stabilization
Packaging
laminated bags [20mL] N2
CO2
N2-CO2 (1:1)
Cultivars
Origin of cultivation
Maceration process
Allagiannis winery
[Markopoulo, Attica ]
Merlot
Syrah
Markopoulo, Attika
pectinolytic enzymes
Avantis Estate
[Chalkida, Evia]
3) Mavrokou-ntoura
Kymi, Evia
Cold maceration under modified atmosphere (70% N2, 30% CO2)
Pilot plant of the department of oenology and beverage technology
[Technological Educational Institute of Athens]
4) Agiorgitiko
Nemea, Korinthos
Four different red wine varieties have been vinificated and two different maceration procedures have been used, so as to study the evolution of phenolics and provide feedback to the industry to improve the process
And have been packaged in laminated bags under different inert atmospheres so as to optimize the storage atmosphere of each variety.

8. (Folin-Ciocalteu assay)
Methods
Samples
Total Phenols
(Folin-Ciocalteu assay)
Chromatography
(SPE  HPLC-DAD,
LC-MS/MS)
Color Measurement
(Spectrophotometer)
Antiradical activity
(DPPH assay)

9. Results and discussion

10. Identification of individual phenolic compounds with HPLC
min 10 20 30 40 50 60
mAU
100
200
300
400
500
520 nm - Anthocyanins
Mv-3-glc
Mv-3-acglc
Mv-3-coumglc
Pt-3-glc
Pn-3-coumglc
Dp-3-glc
Pn-3-glc
Pn-3-acglc
Pt-3-acglc
Pt-3-coumglc
min 10 20 30 40 50 60
mAU 25 75
100
125
150
175
360 nm - Flavonols
Q-3-glcr Q
M-3-glc
Q-3-glc
L-3-glc M
M-3-glcr
I-3-glc
S-3-glc

11. Extraction of phenolic compounds during vinification
Total Phenols [ppm gallic acid]
Free anthocyanins [ppm Mv-3-glc] CI
HUE
Merlot
2143±45
599.7±12
1.126±0.033
0.788±0.002
Syrah
1954±21
527.2±9.7
1.045±0.033
0.726±0.003
Mavrokou-ntoura
2165±69
533.5±23.5
1.039±0.006
0.630±0.002
Agiorgitiko
2550±35
461.2±4.1
0.943±0.006
0.598±0.001

12. Total phenolic content and antiradical activity
% change of antiradical activity between 360 and 600days N2
-23%
CO2
-60%
N2-CO2 (1:1)
-38%
% change of antiradical activity between 360 and 600days N2
-45%
CO2
-50%
N2-CO2 (1:1)
-42%

13. The decline of free anthocyanins during storage
Variety
Packaging atmosphere
Mv-3-glc
Mv-3-acglc
Mv-3-coumglc
k [mon-1] R2
Merlot N2
-0.319
0.998
-0.336
CO2
-0.201
0.990
-0.223
0.983
-0.217
0.863
N2-CO2 (1:1)
-0.239
0.994
-0.262
-0.268
Syrah
-0.175
0.999
-0.192
0.993
0.195
0.960
-0.150
0.995
-0.170
-0.199
0.981
-0.324
-0.333
0.315
Mavrokountoura
-0.259
0.984
-0.247
-0.252
0.977
-0.164
0.911
-0.158
0.882
-0.171
0.865
-0.299
0.986
-0.286
0.992
-0.271
0.997
Agiorgitiko
-0.348
0.920
-0.392
0.913
-0.460
0.901
-0.317
0.795
-0.359
0.785
-0.456
0.842
-0.366
0.937
-0.414
0.928
-0.527
0.964

14. Color parameters

15. Hydrolysis of wine flavonols during storage
% increase of total flavonol aglycones during storage
Merlot N2
20%
CO2
11%
N2-CO2 (1:1)
18%
Syrah
35%
10%
Mavrokountoura 4% 3%

16. Conclusions
The extraction of individual phenolic compounds during maceration differs with time and maceration procedure and optimal conditions can be designed for each variety
Packaging atmosphere can affect the total phenolic content, antiradical activity, and the rate of polymerization reactions between phenolic compounds during wine storage
The use of pectinolytic enzymes during vinification may lead to hydrolysis of certain glycosylated phenolic compounds, whereas increased carbon dioxide concentration during storage may inhibit such enzymatic reactions
Our results showed that industry can select the optimum inert gas consistency for each grape variety, to favor quick reduction of free anthocyanins and wine stability

17. Thank you