Phenolics in Chardonnay
Steve Price ETS Laboratories
February 2018// Portland, OR What are the differences between white and red grapes?
Not much, just anthocyanins
February 2018// Portland, OR Chardonnay
phenolic in • tannin in skins, seeds and stems white grapes • flavonols in skins
• flavan-3-ols in seeds
• cinnamic acids in pulp and skins
• flavanones in skins
February 2018// Portland, OR Phenolics
Benzoic Acids
HO HO
HO COOH
Gallic Acid from seeds and oak Syringic Acid Vanillic Acid
February 2018// Portland, OR Phenolics
Hydroxycinnamic Acids - Esters
HO COOH HOC HO COO C COOH
Caftaric Acid from skins and pulp Coutaric Acid Fertaric Acid
February 2018// Portland, OR Phenolics
Grape Reaction Product (GRP)
HO COOH HOC HO COO C S Glutathione COOH
Caftaric Acid from caftaric acid and glutathione Coutaric Acid Fertaric Acid
February 2018// Portland, OR Phenolics
Hydroxycinnamic Acids
HO
HO COOH
Caffeic Acid from cinnamate esters p-Coumaric Acid Ferulic Acid
February 2018// Portland, OR Phenolics
Flavan-3-ols, Flavanols, Catechins,
OH
OH
HO O
OH OH Catechin from seeds Epicatechin Epigallocatechin Epicatechin gallate
February 2018// Portland, OR Phenolics
Flavonol Glycosides OH
OH
HO O
O Gly
OH O Quercetin from skins Kaemferol Myricetin Isorhamnetin
February 2018// Portland, OR Phenolics
Flavonol aglycones OH
OH
HO O
OH
OH O Quercetin from flavonol glycosides Kaemferol Myricetin Isorhamnetin
February 2018// Portland, OR Phenolics
Flavanones OH
OH
HO O
OH O
Astilbin from grape skins
February 2018// Portland, OR Phenolics
Tannins
Hydrolyzable Tannins
gallic acid ellagic acid sugars simple phenolic acids from oak
February 2018// Portland, OR Phenolics
Tannins from grape skins and seeds
Condensed Tannin or Proanthocyanidins
Catechin Epicatechin Epigallocatechin Epicatechin gallate
2 to >30 subunits
Inumerable combinations From: Jackson 1994
February 2018// Portland, OR Phenolics
Caftaric Acid polyphenol oxidase (PPO) quinones HO glutathione COOH HOC HO COO C COOH
February 2018// Portland, OR Phenolics
February 2018// Portland, OR PPO + O2
Li et al., 2008
February 2018// Portland, OR Phenolics
glutathione brown polymers cysteine aromatic thiols
February 2018// Portland, OR February 2018// Portland, OR February 2018// Portland, OR Chardonnay Skin Contact Trials
February 2018// Portland, OR Skin Contact Experiment Variety: Chardonnay
600 clusters, hand destemmed, berries pooled
1.5 kg berries per container, 3 replicates, fruit lightly crushed at zero time
Temperature: 25°
SO2: 0, 50ppm, 100ppm
Time: 0, 2, 4, 6, 8, 24 hrs
February 2018// Portland, OR tannin • Tannin extraction increases by 6 hrs with SO2 40.0 • by 8 hrs with no SO2 CHA 25/3/04 35.0 no SO2 SO2
30.0 2x SO2
25.0
20.0
15.0
tannin at 280 nm 280 tannin (mg/L)at 10.0
5.0
0.0 0 2 4 6 8 24 contact time (hrs) astilbin • Skin extraction enhanced by SO2! 12 • Time sensitive
no SO2 CHA 25/3/04 10 SO2 2x SO2
8
6 astilbin (mg/L) 4
2
0 0 2 4 6 8 24 contact time (hrs) caftaric acid caftaric acid immediately oxidized 30.0 in the absence of SO2!
no SO2 CHA 25/3/04 25.0 SO2 2x SO2
20.0
15.0
10.0 caftaric acid (mg/L) caftaric
5.0
0.0 0 2 4 6 8 24 contact time (hrs) GRP 25.0 • GRP oxidized in the absence of SO2 no SO2 CHA 25/3/04 SO2 20.0 2x SO2
15.0
GRP GRP (mg/L) 10.0
5.0
0.0 0 2 4 6 8 24 contact time (hrs)
February 2018// Portland, OR A420 • SO2 delays onset of browning 1.400 no SO2 SO2 CHA 25/3/04 2x SO2 1.200
1.000
0.800
0.600 Browning Browning (A420) 0.400
0.200
0.000 0 2 4 6 8 24 contact time (hrs) inverse relationship of caftaric acid and GRP in the presence of SO2 25.0 CHA 25/3/04
20.0
15.0
GRP GRP (mg/L) 10.0
5.0
0.0 0.0 5.0 10.0 15.0 20.0 25.0 30.0
no SO2 caftaric acid (mg/L) Goodfellow 2016 B 2016 2017 gallic acid 4.9 1.7 0.8 catechin 0.8 <0.2 <0.2 astilbin 4.5 1.9 0.7 tannin 19.7 13.8 11.3 GRP 5 4.1 2.9 caftaric acid 8.5 6.8 6.3 caffeic acid 14.1 5.1 5 quercetin glycosides 1.3 0.5 0.4 quercetin 0.8 0.8 <0.2 Winery X 2016 2017 gallic acid 2.8 1.1 catechin <0.2 <0.2 astilbin 0.5 1 tannin 15.4 11.8 GRP 10.1 7.6 caftaric acid 4.8 18.2 caffeic acid 2 5.4 quercetin glycosides <0.2 <0.2 quercetin 0.2 0.4 Chehalem 2017 Oxidative Reductive Hard Press Free Run gallic acid 1.4 0.7 0.7 1 catechin <0.2 <0.2 0.5 <0.2 astilbin 0.8 0.9 1 0.5 tannin 11.6 10.6 12.2 9.1 GRP 2.6 5.6 6.4 6.5 caftaric acid 6.6 10.1 15.6 10.8 caffeic acid 4.4 3.2 3.7 2.4 quercetin glycosides 0.2 0.7 0.7 <0.2 quercetin 0.2 0.2 0.2 <0.2 THANKS www.etslabs.com // facebook.com/etslabs
Dr. Steve Price (541) 908-4279 [email protected] [email protected]
February 2018// Portland, OR