Changes In Volatile Composition Of Virgin Olive - Bio

Changes In Volatile Composition Of Virgin Olive
Oils During Storage Regarding Different
Greek Olive Varieties
Kali Kotsiou, Konstantinos Gennatos, Maria Tasioula-Margari*
Department of Chemistry, Section of Industrial and Food Chemistry,
University of Ioannina, Ioannina 45110, Greece
Corfu, 21-22 February 2014
Introduction
Scientific findings suggest that olive oils have health
benefits that include:
 reduction of risk factors of coronary heart disease,
 prevention of certain cancers,
 immune and inflammatory responses.
Introduction Phenolic and Volatile compounds

Phenolic and volatile compounds are responsible for olive
oils’ sensory characteristics.
 Phenolic compounds  bitter, pungent sensations


Volatile compounds  “fruity” sensation
The occurrence and concentration of hydrophilic phenols
and volatile compounds in VOO
 is related to the activities of various endogenous
enzymes of olive fruit and
 is strongly affected by the extraction conditions.
Volatile Compounds Lipoxygenase pathway
(LA) linoleic acid, (LnA) linolenic acid, (LOX) lipoxygenase, (HPL) hydroperoxide
lyases, (ADH) alcohol dehydrogenase, (AAT) acetyl transferases
Angerosa et al., 2004
Volatile Compounds Development

Stage 1
 Olive
variety
 Fruit storage prior to oil extraction

Stage 2
 Extraction
duration)

(malaxation temperature and
Stage 3
 Olive
oil storage conditions (temperature,
light, headspace)
Objectives
1.
Study of volatile composition of virgin
olive oils of different varieties.
2.
Evaluation of the changes in the volatile
composition of virgin olive oils during
storage.
3.
Correlation to organoleptic assessment.
Olive oil samples
Regions and cultivars:
Zakinthos
Kefalonia
Corfu
– Koroneiki
– Koroneiki
– Lianolia
Preveza-
Lefkada
Lianolia
– Asprolia
Zakinthos
Kefalonia
– “Native”
– Thiaki
Harvesting periods:
(November to early January)
2007 – 2008
2011 – 2012
2012 – 2013
Storage conditions:
 glass bottles (headspace 1%)
 dark
 temperatures below 18 °C
Analytical determinations





Quality indices
 Peroxide value
 Spectroscopic indices (K232, K270)
 Free acidity
Fatty Acids
 GC – FID
Phenolic compounds
 Folin – Ciocalteau
 HPLC – UV
Volatile compounds
 GC-MS
Organoleptic assessment
Initial quality characteristics
Peroxide Value
Koroneiki
Koroneiki
“Native”
“Thiaki”
Lianolia
Lianolia
Asprolia
Zakynthos
Kefalonia
Zakynthos
Kefalonia
Corfu
Preveza
Lefkada
(n=8)
(n=7)
(n=6)
(n=5)
(n=7)
(n=5)
(n=6)
8.77±0.74
8.77±1.23
9.17±0.51
8.00±0.59
7.59+0.57
7.80±0.50
9.16±0.90
0.23±0.09
0.19±0.07
0.30±0.08
0.14±0.02
0.31±0.14
0.25±0.10
0.40±0.21
K270
0.11±0.01
0.10±0.00
0.11±0.00
0.09±0.01
0.14±0.04
0.12±0.01
0.11±0.01
K232
1.31±0.06
1.33±0.06
1.42±0.08
1.25±0.03
1.69±0.12
1.61±0.14
1.44±0.05
C16:0
12.25±0.98
13.43±0.54
13.75±0.64
12.36±1.14
14.85±0.91
11.88±0.29
C16:1
0.98±0.13
1.12±0.12
1.30±0.16
1.06±0.22
1.37±0.27
1.41±0.1
0.88±0.10
C 18:0
2.87±0.20
2.80±0.07
2.64±0.06
2.73±0.32
1.98±0.19
2.01±0.14
2.87±0.26
C 18:1
74.31±1.44
72.50±1.18
71.5±2.00
73.27±3.35
70.36±2.18
69.25±1.74
71.95±0.74
C 18:2
7.41±0.90
7.79±0.89
8.81±1.45
8.35±2.48
9.79±1.5
9.72±1.02
10.18±0.37
C 18:3
0.78±0.08
0.79±0.11
0.71±0.07
0.61±0.08
0.81±0.05
0.82±0.06
0.64±0.05
186±60
141±27
206±80
113±20
114±30
139±25
230±25
[meq/Kg]
Free acidity (expressed
as % of oleic acid)
Fatty acids (%)
14.12±1.2
Total phenolic
compounds (expressed
as mg gallic acid/Kg)
Volatile compounds determination
 Solid-phase microextraction (SPME):
 fiber: 30/50 μm DVB/CAR/PDMS (Supelco, Bellafonte, USA)
 40°C for 45 min
 internal Standard: 4-methyl-2-pentanol
 Analytical determination:
 GC-2010 Plus chromatograph equipped with GCMS-QP2010
mass spectrometer (Shimadzu) or
 HP 6890 chromatograph (Hewlett Packard,Wilmington, DE,
USA) equipped with an HP 5973 mass selective detector
(Wilmington, DE, USA).
 Column: DB-5MS, 60m × 0,32mm × 1μm (J & W Scientific,
Folsom, USA).
Volatile compounds
RT
Compound
RT
Compound
RT
Compound
RT
Compound
2.510
Ethanol
12.006
2-Pentanol, 4-methyl- (IS)
20.352
3-Ethyl-1,5-octadiene
26.679
Octanal
3.293
1,3-Pentadiene
12.453
1-Pentanol
20.610
Heptanal
26.666
3-Hexen-1-ol, acetate, (Z)-
3.458
1,3-Pentadiene, (E)
12.470
Toluene
21.120
2,4-Hexadienal, (E,E)-
27.055
Acetic acid, hexyl ester
6.827
Butanal, 3-methyl-
12.590
2-Penten-1-ol, (Z)-
22.711
3-Ethyl-1,5-octadiene
27.221
2,4-Heptadienal, (E,E)-
7.209
Butanal, 2-methyl-
14.290
3-hexanal, (Z)-
23.160
3-Ethyl-1,5-octadiene
28.365
D-Limonene
7.969
1-Penten-3-ol
14.403
Hexanal
23.981
2-Heptenal, (Z)-
29.146
beta-Ocimene
8.072
1-Penten-3-one
17.433
3-Hexen-1-ol, (E)-
25.540
5-Hepten-2-one, 6-methyl-
30.404
1-Octanol
8.578
3-Pentanone
17.651
2-Hexenal, (E)-
25.844
2-Octanone
32.394
Nonanal
8.684
Pentanal
17.715
3-Hexen-1-ol, (Z)
25.849
beta-Myrcene
33.008
Phenylethyl Alcohol
10.659
1-Butanol, 3-methyl-
18.317
2-Hexen-1-ol, (E)-
25.987
2,6-Octadiene, 4-methyl-
37.613
Unknown
10.853
1-Butanol, 2-methyl-
18.519
1-Hexanol
26.200
1,6-Heptadiene, 3,5-dimethyl-
46.263
alpha-Copaene
11.800
2-Pentenal, (E)-
20.100
3-Ethyl-1,5-octadiene
26.257
1,6-Heptadiene, 2,5-dimethyl-
49.532
alpha-Farnesene
Volatile Compounds in Greek VOO varieties and
their relationship to sensory characteristics
Koroneiki
Rich in: (E)-2-hexenal,
(Z)-3-hexenal
(Z)-3-Hexenyl acetate,
hexyl acetate
Described as:
“fruity”, “freshly cut grass”, “green
leaves”,
medium bitter and pungent
Lianolia
Rich mainly in (E)-2-hexenal
Described as:
“fruity” (apple), “flowers and
herbs”, “chamomile”
medium bitter and pungent
Fruity:4.5-5.5, bitter: 3, pungent: 4
Evolution of total C6 lipoxygenase
pathway products during storage
40,00
35,00
mg/Kg
30,00
25,00
20,00
15,00
10,00
0
Zakynthos- Koroneiki
Preveza - Lianolia
6
Storage (months)
Kefalonia - Koroneiki
Corfu -Lianolia
12
Kefalonia - Thiaki
Lefkada- Asprolia
18
Zakynthos - Native
 An increase was observed during the first 6 months of storage followed by
small a decrease later on.
 The increase was more evident in the samples from Asprolia and Lianolia
variety.
C6 lipoxygenase pathway products:
Linolenic acid: (Z)-3-hexenal, (E)-2-hexenal, (E)-2-hexen-1-ol, (Z)-3-hexen-1-ol and (Z)-3-hexenyl acetate
Linoleic acid: hexanal, hexan-1-ol and hexyl acetate
Evolution of the main aldehydes, which are
responsible for the off-flavors, during storage
140
120
% change
100
80
60
40
20
0
6
12
Storage (months)
Zakynthos- Koroneiki
Kefalonia - Koroneiki
Kefalonia - Thiaki
Preveza - Lianolia
Corfu -Lianolia
Lefkada- Asprolia
18
Zakynthos - Native
 Pentanal, hexanal, heptanal, 2-heptenal and nonanal are the main
compounds which are responsible for ‘rancid” defect.
 Up to 12 months the increase rate was similar for all the studies
varieties.
 At 18 months of storage, the increase of the above compounds was
more evident in the samples from Asprolia and Lianolia variety.
Conclusions
Up to 12 months of storage, the same
formation rate of volatile compounds,
responsible for off-flavors, was observed for
all olive varieties.
Olive oils from more polyunsaturated
varieties, which are also poor in phenolic
compounds may not be able to maintain
their sensory characteristics during the
permitted 18 months period of storage.
THANK YOU
FOR YOUR ATTENTION

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