Effect of Foliar Nitrogen and Sulfur
Applications on Aroma Profile of Vitis
vinifera L. cv. Petit Manseng using Modified
Quantitative Descriptive Analysis
Molly Kelly, Bruce Zoecklein
Virginia Polytechnic Institute and State University
Food Science and Technology
Enology Grape Chemistry Group
•
• Vitis vinifera
Petit Manseng
• Ripens late
• Loose clusters,
minimal rot
• High acid and sugar
• Originally grown in Jurancon
region of France
• Some aroma precursors
similar to those found in
Sauvignon blanc
Study Objectives
• Impact of various vineyard nitrogen and sulfur
applications on yield components and grape
composition
• Influence of vineyard nitrogen and sulfur
fertilization on concentration of free and bound
volatiles in Petit Manseng by acid or enzyme
hydrolysis
• Do vineyard nitrogen and sulfur treatments impact
wine aroma and flavor in this variety and develop
descriptive terms for Petit Manseng wines
Materials and Methods
• Two year study/RCBD
• Vineyard description: P. Manseng on 101-14
rootstock in Dobson, NC, elev. 2,000 ft. Planted
2008 on VSP. Soil was a Clifford sandy clay loam
• Petiole samples at bloom
• Vegetative measurements to determine impact of
vegetative growth
– Pruning weights, cluster weights, point quadrat analysis
(as described by Smart and Robinson 1991)
Materials and Methods
• Juice analysis: ammonia, urea and arginine
were determined enzymatically (Megazyme,
Bray, Ireland) and NOPA was determined
spectrophotometrically
• Electronic nose, (ENose ®, Smiths Detection,
Watford, England) was used to measure
volatile compounds emitted by clusters in the
field and berries in the lab (as described by
Devarajan et al. 2011)
Materials and Methods
• Isolation of glycosides (as described by Günata
et al. 1985)
• Fractionation of free and bound fractions (as
described by Günata et al. 1985)
• Hydrolysis of glycosides using acid/enzyme
hydrolysis (as described by Günata et al. 1985
and Sefton et al. 1993)
• GC-MS for grapes and wines (as described by
Whiton and Zoecklein 2000)
Materials and Methods
• Production of treatment wines using standard winemaking
practices
• Descriptive analysis: Lexicon development with subsequent
intensity training used a combination of the Spectrum™
Descriptive Analysis method and Quantitative Descriptive
Analysis method™
• A 15 cm unstructured line scale was used for intensity rating
• Eleven aroma attributes, ten flavor-by-mouth attributes, two
texture attributes and aftertaste attributes were assessed
Vineyard Nitrogen and Sulfur
Applications
• Four different treatments, six repetitions
– Treatment 1: control
– Treatment 2: soil N @ 30 kg/ha after flowering
– Treatment 3: foliar N @ 15 kg/ha (2 apps prior to
veraison)
– Treatment 4: foliar N and S @ 15 kg/ha and 5 kg/ha
– What impact, if any, will these applications have on
Petit Manseng vine growth/vigor, aroma/flavor
compounds and wine sensory analysis?
Point Quadrat Analysis 2012
Trt 1: control
Trt 2: soil N
Trt 3: foliar N
Trt 4: foliar N + S
Effect of soil and foliar N and S on juice nitrogen
levels (2011)
a
b
b
b
c
c
a
b
c
c
c
c
b
a
Grape Derived Free and
Bound Aroma/Flavor
Free
GrapeDerived
Volatiles
Bound Components
Glycosides
S-cysteine
conjugates
Maturity
Processing
Aging
Aromas/flavors
monoterpenes
Floral
Spice
Floral,
fruity, sweet
Boxwood
norisoprenoids
thiols
esters
Green, grass
Banana,
pineapple
fatty acids
higher
alcohols/aldehydes
Volatile differences in field cluster samples
using electronic nose (2012)
Trt 1: control
Trt 2: soil N
Trt. 2
Trt. 3
Trt 3: foliar N
Trt 4: foliar N + S
Trt. 1
Trt. 4
Volatile differences in lab berry samples
using electronic nose (2012)
Trt 1: control
Trt 2: soil N
Trt 3: foliar N
Trt. 4
Trt. 1
Trt. 3
Trt 4: foliar
N+S
Trt. 2
Effect of soil and foliar N and S on free
aroma/flavor compounds in fruit 2011 (µg/L)
Compound
Control
Soil N
0.83b
Foliar N
Pvalue
0.20b
SIG
2-ethyl-1hexanol
3.24a
n-butanol
2.94e4 a * 3.03e4 a * nd
nd
NS
phenethyl
alcohol
228.10a
3.33b
nd
SIG
Isovaleric acid
6.07e3 a * nd
nd
3.06e3 a *
NS
decanal
3.23a
0.83b
nd
0.20b
SIG
γbutyrolactone
2.71e4 a
2.00e4 ab 1.42e4 c
1.49e4 bc
SIG
nd
nd
Foliar N +S
• different letters within rows indicate significant differences at p<0.05
•nd=none detected
• * indicates OAV>1
Effect of soil and foliar applications of N and S
on acid hydrolysis products in fruit 2011 (µg/L)
Compound
Control
Soil N
Foliar N
Foliar
N+S
P value
1-octen-3-ol
107.43a
139.20a
145.50a
202.52a *
NS
2-ethyl-1hexanol
16.11a
8.39ab
4.22b
9.13ab
SIG
n-hexanol
5.16b
9.17b
9.54b
28.69a
SIG
phenethyl alcohol 1.49e3 a *
nd
543.00a
1.14e3 a
NS
hexyl acetate
394.30b
838.40b
1.92e3a
2.23e3a
SIG
2-ethylhexanoic
acid
80.47a
28.29b
35.96b
51.26ab
SIG
decanal
16.11a
8.39ab
4.22b
9.13ab
SIG
γ-butyrolactone
1.92e4 a *
9.91e3a *
1.11e4 a *
8.55e3 a *
NS
• different letters within rows indicate significant differences at p<0.05
•nd=none detected, * indicates OAV>1
Effect of soil and foliar applications of N and S
on enzyme hydrolysis products in fruit 2011 (µg/L)
Compound
Control
Soil N
Foliar N
Foliar
N+S
P value
1-octen-3-ol
154.18a
136.49ab
31.61b
65.27ab
SIG
n-butanol
3.22e4 a *
nd
nd
1.84e4 a * NS
hexyl acetate
227.70b *
345.90b * 626.80ab *
1.78e3 a * SIG
decanoic acid
0.44b
1.33a
0.14b
0.22b
SIG
myristic acid
423.60a
467.30a
116.50b
133.0b
SIG
trans-2-cis-6nonadienal
nd
6.87a
0.59b
nd
SIG
• different letters within rows indicate significant differences at p<0.05
•nd=none detected
• * indicates OAV>1
Descriptive Analysis
•52 descriptive terms generated in 4 classes
•Aroma
•Flavor-by-mouth
•Texture/mouthfeel
•Aftertaste
•24 attributes evaluated by 8 trained panelists
•15 cm line scale with anchors “low” to
“extreme”
Mean Wine Aroma Intensities 2011
peach
aroma*
6
Trt 1: control
Trt 2: soil N
lime aroma
5
pear aroma*
4
lemon aroma
honeysuckle
aroma*
3
2
1
Trt 3: foliar N
Trt 4: foliar
N+S
0
pineapple
aroma*
floral aroma
grapefruit
aroma*
green apple
aroma*
melon
aroma*
honey
aroma*
Trt 1
Trt 2
Trt 3
Trt 4
* Values are
significantly
different at
p<0.05
Mean Wine Flavor Intensities 2011
honeysuckle
flavor
honey flavor
Trt 1: control
Trt 2: soil N
pear flavor*
6
5
4
3
sweet flavor*
sour flavor*
2
Trt 3: foliar N
orange flavor
Trt 4: foliar N+S
aftertaste*
viscosity*
astringency*
1
0
bitter flavor*
grapefruit*
Trt 1
Trt 2
Trt 3
Trt 4
pineapple*
apple*
* Values are
significantly different
at p<0.05
Possible Effects of soil and foliar N and S on
wine aroma and flavor compounds in 2011
Compound Control
Soil N
Decanoic
acid
8.40e3
±1.34a
8.03e3
±1.19a
Ethyl
octanoate
*5.96e4
±0.31a
*6.32e4
±0.35a
* Indicates OAV>1
Foliar Foliar Descriptors
N
N +S
6.82e3 *3.42e4 Citrus
±0.92a ±2.30a (pineapple,
grapefruit)
*6.39e4 *2.30e5 Fruity
±0.28a ±1.69a (pineapple,
grapefruit)
PCA Aroma compounds 2011
Conclusions
• Treatment effects observed in:
– Free volatile compounds
– Bound components
– Wine sensory attributes
• Significant differences in concentrations of free and bound terpenes,
higher alcohols and esters in P.Manseng juice
• Acid hydrolysis released more terpenes with soil N, foliar N and foliar
N+S applications vs enzymatic hydrolysis
• Ester content increased in soil N, foliar N and foliar N+S treatments in
both acid hydrolysates and enzyme hydrolysates
• Practices to release glycosidically bound compounds may be needed
for full expression of aroma and flavor potential
Practical Benefits
 Optimization of fertilization practices to produce Petit
Manseng wines with increased aromatics/flavors
Optimize winemaking techniques to release glycosidically
bound aroma and flavor compounds
Vineyard nitrogen and nitrogen plus sulfur may be a means
to alter the aroma and flavor profile of Petit Manseng
Descriptive terms generated could be used to standardize
future sensory analysis of this variety
Acknowledgements
Denise Gardner, Enology Extension Specialist, Penn State
Gill Giese, Vineyard manager & winemaker Shelton Vineyards, NC
Mary Simmons, winemaker Mt. Vale Winery, VA
Dr. Clyde Colwell, owner Carolina Heritage Winery, NC
Pat Colwell, owner Carolina Heritage Winery, NC
Dick Connell, owner Blue Zephyr Vineyards, NC
Christina Connell, owner Blue Zephyr Vineyards, NC
Ethan Brown, winemaker Olde Mill Winery, NC
Heather Pena
Kathleen Demers
Virginia Vineyard Association
Virginia Wine Board
North Carolina Winegrowers Assn.
Questions?