Tannin Activity Variation with Maceration

Transcription

1 Tannin Activity Variation with Maceration James A. Kennedy Department of Viticulture and Enology California State University, Fresno Wine Business Innovation+Quality March 4, 2015 St. Helena, CA

2 Objective of Research Group Develop analytical tools in order to effectively manage phenolics in the vineyard and winery.

3 Red Wine Mouthfeel Drivers Major Variable Tannin Concentration What to Measure Tannin Concentration Wine Matrix Tannin Activity Acidity Ethanol Residual sugar Mannoproteins Polysaccharides Skin/Seed Size distribution Color Incorporation Tannin oxidation Indirect measures of tannin activity

4 Proposed Mechanism of Astringency Barak and Kennedy, J. Agric. Food Chem. 2013, 61:

5 Tannin: Interaction vs. Size 100 seed skin CS2010 CS2012 Regression lines Increasing stickiness - H, kj/mol Decreasing Tannin Size GPC Retention, min Barak and Kennedy, J. Agric. Food Chem. 2013, 61:

6 Tannin Addition Revelette et al., J. Agric. Food Chem., 2015, 62:

7 2014 Maceration Experiments Five wineries from Napa Valley Focus on fermentation/maceration Each winery free to define experiment of interest Intent was to generate structure variation Isolate tannins from collected samples 104 samples 10 tanks Aron and Kennedy, J. Agric. Food Chem. 2007, 55:

8 2014 Maceration Experiments Cabernet Sauvignon (one Petit Verdot) Cold soak (7 days) vs no cold soak Same total maceration time (28 days) Extended maceration (26 days) vs no extended maceration (15 days) Extended maceration (62 days) Across several blocks Cabernet Sauvignon vs Petit Verdot

9 2014 Experiments Exhaustively analyze isolates Gravimetric recovery Concentration by chromatography GPC, PLRP, phloroglucinolysis Tannin composition Flavan-3-ol subunit Color incorporation Conversion yield Tannin size distribution Compare with corresponding tannin activity

10 A Gel Permeation Chromatography B Cumulative Mass Distribution (%) ,339 g/mol 842 g/mol 10% v/v Et 22 Brix 23 Brix 24 Brix Cumulative Mass Distribution (%) ,647 g/mol 959 g/mol 20% v/v Et 22 Brix 23 Brix 24 Brix Brix Brix 0 0 2,000 4,000 6,000 8,000 10,000 Molecular mass (g/mol) 0 0 5,000 10,000 15,000 Molecular mass (g/mol) C D Cumulative Mass Distribution (%) ,604 g/mol 1,124 g/mol 50% v/v Et 22 Brix 23 Brix 24 Brix 26 Brix Cumulative Mass Distribution (%) ,203 g/mol 3,415 g/mol 70% v/v acetone 23 Brix 24 Brix 26 Brix 0 0 5,000 10,000 15,000 20,000 Molecular mass (g/mol) 0 0 5,000 10,000 15,000 20,000 25,000 30,000 Molecular mass (g/mol) Bindon et al., J. Agric. Food Chem. 2014, 62:

11 HO 6 HO 8 8 α A 4α O C HO ' O HO B 2 ' O HO 3 ' O O O O Proanthocyanidin (Tannin) Structure & Reactivity Reactivity Acid-catalysis Oxidation HO A O C + Oxidation Center Nucleophilic Center Electrophilic Center B

12 Determining Tannin Structure Phloroglucinol Analysis: HPLC Analysis Pre-Veraison Grape Tannin 60-80% Mass Conversion HPLC Analysis 10-40% Mass Conversion Wine Tannin McRae et al., J. Agric. Food Chem., 2010, 58:

13 Gravimetric Recovery (g/l) Concentration Comparison YY = xx RR 2 = [GPC] (g/l)

14 Preliminary Results - PCA

15 Gravimetric Concentration vs. Time Gravimetric Concentration, g/l Time, days

16 8000 Tannin Activity vs. Time Tannin Stickiness, -J/mol Why is tannin activity declining with soak time? Time, days

17 4600 Average Molecular Mass, g/mol %EGC: 32.1 %ECG: 4.3 Conv. Yield: 53.9 %520: 16.8 Data indicates that seed tannin increasing %EGC: 21.6 %ECG: 5.3 Conv. Yield: 54.8 %520: Time, days

18 Berry Integrity: Skin and Seed Tannin Extraction Proanthocyanidin concentration (mg/l) % Skin Skin Proanthocyanidins Seed Proanthocyanidins 59% Skin 72% Skin 79% Skin Day 9 73% Skin Proanthocyanidin concentration (mg/l) % Skin Skin Proanthocyanidins Seed Proanthocyanidins 53% Skin 63% Skin 56% Skin Day 17 55% Skin % Crushed berries % Crushed berries Cerpa-Calderon and Kennedy, J. Agric. Food Chem., 2008

19 Revelette et al., Pract. Winery Vineyard, 2015, Jan.: 32-37

20 Concentration*Stickiness vs Time Concentration*Stickiness Time, days

21 Acknowledgements Wine Business Monthly Research Group Ralph Yacco Undergraduate students: Melanie Sherman Rebecca Wulf Sasha Hazel Aude Watrelot Funding and Support American Vineyard Foundation CSU - Agricultural Research Institute Napa Valley wineries