Cooling treatment of olive paste during the oil processing: Impact on the yield and extra virgin olive oil quality


Veneziani, G.; Esposto, S.; Taticchi, A.; Urbani, S.; Selvaggini, R.; Di Maio, I.; Sordini, B.; Servili, M.

Food Chemistry 221: 107-113

2017


In recent years, the temperature of processed olives in many olive-growing areas was often close to 30°C, due to the global warming and an early harvesting period. Consequently, the new trends in the extraction process have to include the opportunity to cool the olives or olive paste before processing to obtain high quality EVOO. A tubular thermal exchanger was used for a rapid cooling treatment (CT) of olive paste after crushing. The results did not show a significant difference in the oil yield or any modifications in the legal parameters. The cooling process determined a significant improvement of phenolic compounds in all the three Italian cultivar EVOOs analyzed, whereas the volatile compounds showed a variability largely affected by the genetic origin of the olives with C<sub>6</sub> aldehydes that seem to be more stable than C<sub>6</sub> alcohols and esters.

Food
Chemistry
221
(2017)
107-113
FOOD
CHEMISTRY
Contents
lists
available
at
ScienceDirect
Food
Chemistry
ELSEVIER
journal
homepage:
www.elsevier.com/locate/foodchem
Cooling
treatment
of
olive
paste
during
the
oil
processing:
Impact
CrossMark
on
the
yield
and
extra
virgin
olive
oil
quality
G.
Veneziani
,
S.
Esposto,
A.
Taticchi,
S.
Urbani,
R.
Selvaggini,
I.
Di
Maio,
B.
Sordini,
M.
Servili
Department
of
Agricultural,
Food
and
Environmental
Sciences,
University
of
Perugia,
Via
S.
Costanzo,
06126
Perugia,
Italy
ARTICLE INFO
ABSTRACT
Article
history:
Received
25
July
2016
Received
in
revised
form
10
October
2016
Accepted
16
October
2016
Available
online
17
October
2016
In
recent
years,
the
temperature
of
processed
olives
in
many
olive-growing
areas
was
often
close
to
30
°C,
due
to
the
global
warming
and
an
early
harvesting
period.
Consequently,
the
new
trends
in
the
extraction
process
have
to
include
the
opportunity
to
cool
the
olives
or
olive
paste
before
processing
to
obtain
high
quality
EVOO.
A
tubular
thermal
exchanger
was
used
for
a
rapid
cooling
treatment
(CT)
of
olive
paste
after
crushing.
The
results
did
not
show
a
significant
difference
in
the
oil
yield
or
any
modifications
in
the
legal
parameters.
The
cooling
process
determined
a
significant
improvement
of
phenolic
compounds
in
all
the
three
Italian
cultivar
EVOOs
analyzed,
whereas
the
volatile
compounds
showed
a
variability
largely
affected
by
the
genetic
origin
of
the
olives
with
C5
aldehydes
that
seem
to
be
more
stable
than
C5
alcohols
and
esters.
©
2016
Elsevier
Ltd.
All
rights
reserved.
Keywords:
Technological
innovation
Cooling
treatment
Heat
exchanger
Olive
oil
quality
Polyphenols
Volatile
compounds
I.
Introduction
The
continuous
changes
associated
with
the
evolution
of
the
olive
oil
sector
mainly
regard
the
technological
innovations
focusing
on
the
oil
yield
and
quality
improvement
of
the
product
(Abenoza
et
al.,
2013;
Bejaoui,
Beltran,
Aguilera,
&
Jimenez,
2016;
Clodoveo,
Durante,
&
La
Notte,
2013;
Esposto
et
al.,
2013;
Jimenez,
Beltran,
&
Uceda,
2007;
Leone,
Tamborrino,
Romaniello,
Zagaria,
&
Sabella,
2014;
Leone
et
al.,
2015;
Puertolas
&
Martinez
de
Maration,
2015;
Veneziani
et
al.,
2015).
This
is
evaluated
using
specific
markers,
such
as
phenolic
and
volatile
compounds
related
to
the
health
and
sensory
properties
of
extra
virgin
olive
oil
(EV00)
(El
Riachy,
Priego-Capote,
Leon,
Luis
Rallo,
&
Luque
de
Castro,
2011;
Garrido-Delgado,
Dobao-Prieto,
Arce,
&
Valcarcel,
2015;
Servili
et
al.,
2004;
Veneziani
et
al.,
2015;
Vitaglione
et
al.,
2015).
New
applications
in
the
EVO0
industry,
such
as
ultrasound,
a
microwave
assisted
system,
a
pulsed
electric
field
and
heat
exchanger,
were
aimed
to
define
a
positive
impact
on
the
working
efficiency
of
the
continuous
extraction
system.
In
several
cases,
these
were
associated
with
an
increase
in
polyphenols
and
volatile
compounds.
*
Corresponding
author.
E-mail
addresses:
(G.
Veneziani),
unipg.it
(S.
Esposto),
(A.
Taticchi),
(S.
Urbani),
(R.
Selvaggini),
(I.
Di
Maio),
(B.
Sordini),
(M.
Servili).
http://dx.doLorg/10.1016/j.foodchem.2016.10.067
0308-8146/©
2016
Elsevier
Ltd.
All
rights
reserved.
Tubular
heat
exchangers
applied
after
olive
crushing
were
introduced
into
the
mechanical
extraction
process
of
the
oil
thanks
to
their
capacity
to
establish
a
rapid,
continuous,
thermal
condi-
tioning
of
the
olive
paste
prior
to
malaxation
(Esposto
et
al.,
2013;
Leone
et
al.,
2015;
Veneziani
et
al.,
2015).
This
heating
treat-
ment
can
reduce
malaxation
times,
increase
the
phenolic
concen-
trations
and
modify
the
aromatic
fractions
of
oils,
according
to
the
genetic
origins
of
the
olives
processed
(
ieneziani
et
al.,
2015).
An
important
factor,
related
to
the
use
of
thermal
conditioning
of
olive
paste,
regards
the
increasingly
widespread
need
to
adapt
to
the
new
agronomic
practices,
such
as
early
harvesting,
during
which
the
oil
is
often
extracted
from
olives
that
could
reach
tem-
peratures
over
30
°C
during
crushing,
with
a
negative
impact
on
EVO0
quality.
The
new
challenge
of
the
olive
oil
sector,
therefore,
concerns
the
problem
of
global
warming
and
the
consequent
rise
in
temperature
not
only
in
the
entire
Mediterranean
area,
but
also
in
other
olive-
growing
areas,
such
as
South
America,
South
Africa
and
Australia.
High
temperatures
during
the
harvesting
period
may,
therefore,
determine
the
transformation
of
olives
characterised
by
tempera-
tures
which
are
too
high
for
EVO0
to
achieve
adequate
amounts
of
phenolic
and
volatile
compounds,
responsible
for
the
health
and
sensory
properties
of
the
product.
The
climatic
changes,
combined
with
the
new
trends
to
anticipate
the
olive
harvesting
period,
lead
to
the
need
to
thermally
control
the
olive
paste,
not
merely
for
heating,
but
most
of
all
to
determine
a
cooling
treat-
ment.
The
rapid
cooling
of
the
olive
paste
using
a
tubular
heat
108
G.
Veneziani
et
all
Food
Chemistry
221
(2017)
107-113
exchanger
represents
an
innovative
technology,
which
was
intro-
duced
for
the
first
time
in
the
mechanical
extraction
process
of
olive
oil,
and
which
will
be
essential
whenever
the
thermal
condi-
tion
of
pastes
before
the
malaxation
process
is
above
the
optimal
temperature
to
extract
a
high
quality
EVOO.
Nowadays
however,
there
are
no
studies
regarding
the
lowering
of
olive
paste
temper-
ature,
which
could
be
compared
to
the
use
of
cold,
climatic
cham-
bers
to
store
the
olives
(Luaces,
Perez,
&
Sanz,
2005,
2006)
or
to
the
use
of
dry
ice,
both
of
which
practices
are
not
easily
adaptable
to
an
industrial
oil
transformation
process.
The
use
of
heat
exchangers
to
cool
the
olive
paste
will
make
the
extraction
plants
more
adaptable
to
different
variables
and
changes
(cultivars,
new
agronomic
practices,
degree
of
ripening,
climatic,
seasonal
pattern,
etc.)
and
maintain
a
high
quality
standard
of
EV00.
The
aim
of
the
study
regarded
the
introduction
of
a
new
techno-
logical
evolution
in
the
mechanical
extraction
process
of
oil,
based
on
cooling
the
olive
paste
and
its
impact
on
the
oil
yield,
the
legal
quality
parameters
and
the
phenolic
and
volatile
composition
of
EWO.
2.
Materials
and
methods
2.1.
Chemicals
Hydroxytyrosol
(3,4-DHPEA)
and
tyrosol
(p-HPEA)
were
sup-
plied
respectively
by
Fluka
(Milan,
Italy)
and
Cabru
s.a.s.
(Arcore,
Milan,
Italy)
whereas
the
dialdehydic
forms
of
elenolic
acid
linked
to
3,4-DHPEA
and
p-HPEA
(3,4-DHPEA-EDA
and
p-HPEA-EDA),
the
isomer
of
oleuropein
aglycon
(3,4-DHPEA-EA)
and
lignans
((+)-1-
acetoxypinoresinol
and
(+)-pinoresinol)
were
obtained
as
described
by
Montedoro
et
al.
(1993)
and
Servili,
Baldioli,
Selvaggini,
Macchioni,
and
Montedoro
(1999).
All
the
analytical
standards
of
volatile
compounds
Fluka
and
Aldrich
were
purchased
from
Sigma-Aldrich
(Milan,
Italy).
2.2.
Mechanical
EVO0
extraction
process
EVOOs
were
extracted
from
olives
of
the
Coratina,
Peranzana,
and
Ottobratica
cultivars.
Ottobratica
olives
were
harvested
in
Calabria
region
(Reggio
Calabria)
whereas
the
growing
area
of
Coratina
and
Peranzana
cultivars
was
Apulia
region,
in
the
pro-
vince
of
Bari
and
in
the
province
of
Foggia,
respectively.
The
olives
of
all
cultivars
were
harvested
during
the
period
between
the
end
of
September
and
the
last
week
in
October
2014,
and
the
ripening
stage
of
these
olives,
evaluated
on
the
basis
of
the
pigmentation
index
according
to
the
method
of
Pannelli,
Servili,
Selvaggini,
Baldioli,
and
Montedoro
(1994),
were
similar
among
the
cultivars
used
and
corresponded
to
0.95,
0.90
and
0.98
for
Peranzana,
Coratina
and
Ottobratica,
respectively.
The
olives
were
processed
within
48
h
after
harvesting,
with
an
average
temperature
of
the
olives
before
processing
of
approximately
27
°C.
Approximately
150
kg
of
each
olive
cultivar
was
processed
in
triplicate,
using
an
industrial
plant
TEM
200
system
(Toscana
Enologica
Mori,
Tavarnelle
Val
di
Pesa,
Florence,
Italy)
described
by
Veneziani
et
al.
(2015).
The
control
trials
were
carried
out
with
an
EVO-Line
heat
exchanger
(Alfa
Laval
S.p.A.),
placed
before
the
malaxer
(Veneziani
et
al.,
2015)
and
used
for
the
heating
or
cooling
treatment
of
the
olive
paste
at
25
°C
or
30
°C
in
relation
to
the
inlet
temperatures
of
the
olives.
The
pastes
of
experimental
tests
were
instantaneously
cooled,
using
the
same
heat
exchanger
capable
of
determining
a
flash
CT
at
15
°C.
The
heated
or
cooled
olive
pastes
were
then
malaxed
for
30
min
at
25
°C
or
30
°C
and
the
oil
was
extracted
by
centrifugation.
Another
trial
was
carried
out
using
dry
ice
(70
kg/ton
of
olives)
during
the
crushing
step
only
for
the
cv.
Ottobratica,
in
order
to
determine
a
rapid
cooling
treatment
of
the
olive
paste
at
15
°C.
This
also
used
dry
ice
(CT-DI)
to
control
the
thermal
increase
during
this
first
extraction
phase
and
the
results
were
compared
with
the
oil
extracted
with
a
cooling
treatment
and
applied
only
post crushing
using
the
EVO-Line
heat
exchanger
at
25
°C
of
malaxation.
2.3.
EVO0
analyses
2.3.1.
Legal
quality
parameters
The
free
acidity,
peroxide
value,
and
the
UV
absorption
charac-
teristics
(
K232,
K270
and
AK)
of
oils
were
evaluated
in
accordance
with
the
European
Official
Methods
(E.U.
Off.
J.
Eur.
Communities,
2003).
2.3.2.
Moisture
content
The
determination
of
pomace
moisture
content
was
performed
with
a
drying
chamber
Binder
ED
56
(Binder,
Tuttlingen,
Germany),
about
200
g
of
pomace
was
dried
at
105
°C
for
24
h.
2.3.3.
Oil
content
The
pomace
oil
content
was
analyzed
with
Foss-Let
15310
(A/S
N.
Foss
Electric
Denmark),
22.5
g
of
dried
pomaces
were
mixed
(Homogenizer,
A/S
N.
Foss
Electric
Denmark)
with
120
mL
of
tetra-
chloroethylene
and
anhydrous
sodium
sulphate
for
2
min,
and
then
estimated.
2.3.4.
Phenolic
compounds
The
HPLC
analysis
of
phenolic
compounds
of
EVOOs
was
carried
out
using
Agilent
Technologies
system,
model
1100
(vacuum
degasser,
quaternary
pump,
autosampler,
thermostatted
column
compartment,
diode
array detector
(DAD),
fluorescence
detector
(FLD))
controlled
by
ChemStation
(Agilent
Technologies,
Palo
Alto,
CA,
USA)
to
evaluate
the
chromatographic
data
as
described
by
Selvaggini
et
al.
(2006).
Phenolic
compounds
were
evaluated
using
a
Spherisorb
ODS-1
250
mm
x
4.6
mm
column
with
a
particle
size
of
5µm
(Waters,
Milford,
MA,
USA).
The
mobile
phase
consisted
of
0.2%
acetic
acid
(pH
3.1)
in
water
(solvent
A)/
methanol
(solvent
B)
at
a
flow
rate
of
1
mL/min.
The
gradient
changed
as
follows:
95%
A
for
2
min,
75%
A
in
8
min,
60%
Ain
10
min,
50%
A
in
16
min,
and
0%
A
in
14
min
and
was
maintained
for
10
min.,
the
total
running
time
was
73
min.
All
phenolic
compounds
were
detected
by
DAD
at
278
nm
with
the
only
exception
of
lignans
detected
by
FLD,
acti-
vated
at
an
excitation
wavelength
of
280
nm
and
emission
at
339
nm
(Servili,
Baldioli,
Selvaggini,
Miniati,
et
al.,
1999).
2.3.5.
Volatile
compounds
The
evaluation
and
quantification
of
volatile
compounds
in
EVOOs
were
done
by
headspace,
solid-phase
microextraction,
followed
by
gas
chromatography-mass
spectrometry
(HS-SPME/
GC-MS),
according
to
Servili,
Selvaggini,
Taticchi,
and
Montedoro
(2001)
with
few
modifications
as
explained
below.
Six
grams
of
oil
with
the
addition
of
50
tiL
of
a
standard
methanolic
solution,
con-
sisting
of
butanal,
isobutyl
acetate
and
1-nonanol,
were
mixed
for
1
min.
The
SPME
operations,
automated
by
means
of
the
Varian
CP
8410
Autoinjector
(Varian,
Walnut
Creek,
CA),
were
applied
expos-
ing
the
SPME
fiber
(a
50/30
p.m,
1
cm-long,
DVB/Carboxen/PDMS,
Stableflex;
Supelco,
Inc.,
Bellefonte,
PA)
to
the
vapour
phase
of
the
sample,
held
at
35
°C,
for
30
min.
The
fiber
was
then
inserted
into
the
gas
chromatograph
(GC)
injector,
set
in
splitless
mode,
using
a
splitless
inlet
liner
of
0.75
mm
ID
for
thermal
desorption,
and
left
for
10
min.
A
Varian
4000
GC-MS
equipped
with
a
1079
split/
splitless
injector
(Varian,
Walnut
Creek,
CA)
was
used.
A
fused-
silica
capillary
column
was
employed
(DB-Wax-ETR,
50
m,
0.32
mm
ID,
1µm
film
thickness;
J&W
Scientific,
Folsom,
CA).
The
column
was
operated
with
helium
at
a
constant
flow
rate
of
1.7
mL/min,
maintained
by
an
electronic
flow
controller
(EFC).
The
GC
oven
heating
programme
was
performed
as
described
by
G.
Veneziani
et
al]
Food
Chemistry
221
(2017)
107-113
109
Table
1
Evaluation
of
moisture
and
oil
content
of
olive
pomace
obtained
at
different
operative
conditions.
Malaxation
temperature
25
°C
30
°C
Control
CT
Control
b
CT
cv.
Coratina
Moisture
content
(%)
63.9
(0.7)a
65.5
(1.2)a
64.1
(0.5)a
63.6
(0.5)a
Oil
content
(%
d.w.)
cv.
Ottobratica
93
(0.5)a
10.1
(0.2)a
93
(1.1)a
10.2
(1.1)a
Moisture
content
(%)
63.4
(0.3)ab
61.4
(1.7)a
65.0
(1.2)b
633
(0.4)ab
Oil
content
(%
d.w.)
cv.
Peranzana
12.8
(0.5)a
113
(0.8)ab
12.1
(0.8)ab
11.0
(0.1)b
Moisture
content
(%)
643
(0.2)ab
64.7
(0.8)a
643
(0.4)ab
61.1
(0.6)b
Oil
content
(%
d.w.)
10.6
(03)a
9.8
(0.4)a
10.4
(2.5)a
11.5
(0.7)a
d.w.
=
dry
weight.
a
Data
are
the
mean
of
three
independent
experiments
analyzed
twice,
and
the
standard
deviation
is
reported
in
brackets.
Values
with
the
same
letters
in
each
row
(a-b)
are
not
significantly
different
(p
<
0.05).
b
cr
=
cooling
treatment.
Table
2
Evaluation
of
phenolic
compounds
(mg/kg)
of
EVOOs
Control
and
CT
extracted
at
different
operative
conditions.
Malaxation
temperature
25
°C
30
°C
Control
CT
Control
b
CT
cv.
Coratina
3,4-DHPEA
5.1
(0.1)a
10.9
(0.03)b
5.1
(0.1)a
73
(0.2)c
p-HPEA
10.0
(0.2)a
23.6
(0.1)b
5.6
(0.7)c
7.8
(0.4)d
3,4-DHPEA-EDA
505.8
(1.8)a
5173
(2.9)b
730.4
(3.2)c
741.4
(4.2)d
p-HPEA-EDA
123.7
(0.5)a
127.5
(0.1)b
136.9
(1.9)c
138.0
(1.4)c
3,4-DHPEA-EA
2353
(0.4)a
240.7
(0.2)a
355.4
(4.5)b
368.1
(8.0)c
Ligstroside
aglycon
22.7
(0.01)a
30.8
(1.0)b
25.1
(0.5)c
27.4
(03)d
(+)-1-Acetoxypinoresinol
44.5
(0.002)ab
43.4
(0.4)a
46.5
(0.8)ab
47.7
(0.6)b
(+)-Pinoresinol
23.8
(0.005)a
22.8
(0.1)b
22.7
(03)b
21.1
(0.1)c
Total
phenols
cv.
Ottobratica
970.8
(1.9)a
1016.9
(3.1)b
1327.8
(6.0)c
1358.9
(9.2)d
3,4-DHPEA
21.5
(0.1)a
20.6
(0.03)b
23.1
(0.02)c
163
(0.2)d
p-HPEA
17.1
(0.04)a
16.7
(0.02)b
13.1
(0.1)c
143
(0.2)d
3,4-DHPEA-EDA
205.0
(0.7)a
251.1
(0.6)b
297.2
(0.2)c
324.8
(8.1)d
p-HPEA-EDA
463
(0.1)a
48.2
(0.01)b
50.4
(0.1)c
553
(0.9)d
3,4-DHPEA-EA
78.0
(0.1)a
80.2
(0.1)b
94.0
(0.5)c
100.1
(1.1)d
Ligstroside
aglycon
73
(0.003)a
7.6
(0.03)b
9.7
(0.1)c
8.4
(0.1)d
(+)-1-Acetoxypinoresinol
21.5
(0.05)a
23.8
(0.1)b
23.5
(0.1)c
26.0
(0.2)d
(+)-Pinoresinol
39.5
(0.1)a
40.4
(0.1)b
36.5
(0.1)c
41.6
(0.5)d
Total
phenols
cv.
Peranzana
436.2
(0.8)a
488.5
(0.6)b
547.5
(0.6)c
586.9
(83)d
3,4-DHPEA
13
(0.1)a
3.8
(0.2)b
3.6
(0.4)bc
3.1
(0.04)c
p-HPEA
4.9
(0.2)a
8.8
(0.1)b
6.5
(0.1)c
6.4
(0.1)c
3,4-DHPEA-EDA
255.6
(1.6)a
405.6
(9.6)b
320.2
(4.4)c
467.7
(83)d
p-HPEA-EDA
40.0
(0.2)a
74.5
(1.1)b
45.4
(0.2)c
75.5
(0.6)b
3,4-DHPEA-EA
38.8
(0.1)a
72.6
(0.9)b
43.8
(1.4)c
86.9
(1.4)d
Ligstroside
aglycon
2.7
(0.04)a
9.7
(0.1)b
3.7
(0.04)a
10.5
(0.2)b
(+)-1-Acetoxypinoresinol
17.6
(0.04)a
16.8
(0.1)a
18.5
(0.2)ab
21.9
(3.0)b
(+)-Pinoresinol
15.5
(0.007)a
15.2
(0.5)ab
14.8
(0.2)b
19.9
(03)c
Total
phenols
376.4
(1.6)a
606.9
(9.7)b
456.5
(7.5)c
691.9
(9.0)d
a
Data
are
the
mean
of
three
independent
experiments
analyzed
twice,
and
the
standard
deviation
is
reported
in
brackets.
Values
with
the
same
letters
in
each
row
(a-d)
are
not
significantly
different
(p
<
0.05).
b
cr
=
cooling
treatment.
Veneziani
et
al.
(2015).
The
total
analysis
time
was
80
min.
The
mass
spectra
and
retention
times
of
each
volatile
compounds
were
com-
pared
with
the
authentic
reference
compounds.
The
results
of
the
peak
areas
were
calculated
on
the
basis
of
the
relative
calibration
curve
for
each
compound
and
expressed
in
µg/kg
of
oil
(Servili
et
al.,
2001).
2.4.
Statistical
analysis
The
statistically
significant
differences
of
data
were
calculated
by
one-way
ANOVA
using
SigmaPlot
software
package
12.3
(Systat
Software
Inc.,
San
Jose,
CA,
USA).
3.
Results
and
discussion
The
first
parameter
analyzed
to
evaluate
the
impact
of
the
introduction
of
CT
of
olive
pastes
into
the
oil
extraction
process
was
oil
yield.
This
did
not
show
significant
modifications
according
to
the
results
related
to
the
oil
content
of
pomaces
reported
in
Table
1.
In
fact,
the
slight
variations
in
the
residual
pomace
oil
shown
between
the
different
tests
cannot
be
attributable
to
the
cooling
treatment
of
olive
paste.
The
legal
quality
parameters
of
EVOO,
such
as
free
acidity,
per-
oxide
values,
K232,
1
(270
and
AK,
were
not
affected
by
the
CT
of
olive
pastes
(data
not
shown).
110
G.
Veneziani
et
all
Food
Chemistry
221
(2017)
107-113
Table
3
Evaluation
of
volatile
compounds
(µg/kg)
of
EVOOs
Control
and
Cr
extracted
at
different
operative
conditions.
Malaxation
temperature
25
°C
30
°C
Control
CT
Control
CT
cv.
Coratina
Aldehydes
(E)-2-Pentenal
132
(1)a
103
(11)b
132
(3)a
109
(3)b
Hexanal
1228
(7)a
1229
(57)a
1297
(8)ab
1351
(38)b
(E)-2-Hexenal
153429
(3211)ab
156300
(283)a
148179
(2000)b
154000
(3960)ab
(E,E)-2,4-Hexadienal
2139
(149)a
2049
(2)a
2428
(25)b
1955
(36)a
2,4-Hexadienal
(i)
1327
(123)ab
1318
(7)a
1497
(34)b
1285
(26)a
Alcohols
1-Penten-3-ol
1019
(50)a
883
(54)b
1056
(29)a
965
(18)c
(E)-2-Penten-l-ol
938
(35)ab
835
(9)a
1023
(12)b
873
(2)a
1-Hexanol
2492
(30)a
3858
(100)b
1075
(33)c
4633
(88)d
(Z)-3-Hexen-l-ol
890
(3)a
876
(2)a
824
(13)b
434
(14)c
(E)-2-Hexen-l-ol
2760
(100)a
3160
(6)b
2810
(33)a
3570
(64)c
Esters
Hexyl
acetate
143
(6)a
79
(2)b
97
(8)c
41
(4)d
(Z)-3-Hexenyl
acetate
cv.
Ottobratica
71
(6)a
36
(3)b
72
(1)a
28
(2)b
Aldehydes
(E)-2-Pentenal
100
(3)a
106
(1)b
106
(1)b
99
(1)a
Hexanal
687
(1)a
650
(9)b
572
(4)c
741
(5)d
(E)-2-Hexenal
100237
(858)a
113545
(716)b
104685
(746)c
105013
(446)c
(E,E)-2,4-Hexadienal
1532
(32)a
1609
(1)b
1603
(26)b
1595
(22)ab
2,4-Hexadienal
(i)
959
(7)a
1016
(2)b
1011
(9)b
1001
(26)b
Alcohols
1-Penten-3-ol
528
(14)a
536
(4)a
557
(21)a
531
(8)a
(E)-2-Penten-l-ol
434
(14)a
425
(6)a
446
(13)a
423
(6)a
1-Hexanol
5190
(10)a
1978
(21)b
3762
(53)c
2856
(20)d
(Z)-3-Hexen-l-ol
1893
(5)a
1534
(4)b
2247
(60)c
1749
(32)d
(E)-2-Hexen-l-ol
5995
(69)a
3076
(21)b
4590
(33)c
4258
(42)d
Esters
Hexyl
acetate
94
(1)a
132
(4)b
128
(1)b
197
(6)c
(Z)-3-Hexenyl
acetate
cv.
Peranzana
210
(1)a
282
(10)b
305
(26)b
446
(13)c
Aldehydes
(E)-2-Pentenal
218
(3)a
217
(5)a
219
(6)a
138
(2)b
Hexanal
1433
(6)ab
1439
(81)ab
1371
(10)b
1536
(81)b
(E)-2-Hexenal
138950
(7990)a
141265
(498)a
115443
(7414)b
116060
(503)b
(E,E)-2,4-Hexadienal
2613
(168)a
2575
(22)ab
2791
(36)a
2348
(61)b
2,4-hexadienal
(i)
1632
(170)a
1765
(6)a
1700
(65)a
1357
(32)b
Alcohols
1-Penten-3-ol
786
(4)a
779
(11)a
832
(29)b
762
(4)a
(E)-2-Penten-l-ol
766
(1)a
864
(26)b
790
(12)c
780
(4)d
1-Hexanol
1023
(34)a
1135
(8)b
2082
(4)c
1579
(17)d
(Z)-3-Hexen-l-ol
1005
(11)a
1060
(18)b
1170
(1)c
753
(16)d
(E)-2-Hexen-l-ol
1678
(49)a
1375
(39)b
2981
(33)c
1785
(2)d
Esters
Hexyl
acetate
952
(13)a
2616
(131)b
1132
(40)a
1856
(81)c
(Z)-3-Hexenyl
acetate
1083
(37)a
1793
(106)b
1294
(42)c
1372
(74)c
'
Data
are
the
mean
of
three
independent
experiments
analyzed
twice,
and
the
standard
deviation
is
reported
in
brackets.
Values
with
the
same
letters
in
each
row
(a-d)
are
not
significantly
different
(p
<
0.05).
b
Cr
=
cooling
treatment.
As
reported
in
Table
2,
the
rapid
cooling
of
the
olive
paste
at
15
°C,
which
determined
a
thermal
reduction
of
approximately
12
°C
for
all
the
cultivars
analyzed,
was
able
to
produce
a
signifi-
cant
increase
of
phenolic
concentration
in
the
EVOOs
extracted
at
different
temperatures
of
malaxation
in
all
three
Italian
cultivars
studied.
These
results
can
be
due
to
the
inhibitory
effect
of
polyphenoloxidase
(PPO)
as
a
result
of
the
cooling
of
the
pastes.
In
fact,
the
PPO
shows
the
optimal
temperature
of
activity
at
approximately
50
°C,
whereas
it
has
a
greatly
reduced
level
of
enzymatic
activities
at
temperatures
below
20
°C,
as
described
by
Taticchi
et
al.
(2013).
These
results
confirmed
what
had
previously
been
observed
by
Garcia-Rodriguez,
Romero-Segura,
Sanz,
and
Perez
(2015),
as
regards
the
increase
of
phenolic
concentration
in
EVO0
obtained
by
a
partial
inhibition
of
PPO
during
crushing.
However,
the
quantitative
modifications
of
phenolic
amount
due
to
the
CT
application
were
strictly
affected
by
the
genetic
origins
of
the
olives.
Variability
ranged
between
the
minimum
increase
of
2.3%
for
cv.
Coratina
malaxed
at
30
°C
and
the
maximum,
corre-
sponding
to
61.2%
for
the
oil
of
cv.
Peranzana
extracted
at
25
°C
of
malaxation.
The
oils
of
cv.
Coratina,
characterised
by
a
high
con-
centration
of
polyphenols,
showed
the
lowest
quantitative
and
qualitative
variability
as
a
result
of
the
rapid
cooling
treatment
of
olive
paste,
with
a
rare
slight
increase
of
over
10
mg/kg
of
EVO0
for
each
phenolic
compound.
The
cv.
Ottobratica
showed
an
increase,
mainly
due
to
3,4-DHPEA-EDA,
of
12%
and
7.2%
of
total
phenols
for
the
oil
malaxed
at
25
°C
and
30
°C,
respectively.
G.
Veneziani
et
al]
Food
Chemistry
221
(2017)
107-113
111
More
significant
variations
of
phenolic
fraction
were
found
in
CT
oils
of
cv.
Peranzana,
characterised
by
a
higher
concentration
of
3,4-DHPEA-EDA,
p-HPEA-EDA
and
3,4-DHPEA-EA,
able
to
guar-
antee
increases
of
above
50%
of
the
total
phenols
in
all
CT
oils
extracted.
As
reported
in
other
studies,
the
lignans,
(+)-1-
acetoxypinoresinol
and
(+)-pinoresinol,
showed
the
lowest
vari-
ability
between
phenolic
compounds
under
the
different
operating
extraction
conditions
for
all
the
cultivars
analyzed
(Selvaggini
et
al.,
2014;
Veneziani
et
al.,
2015),
even
though
higher
percentage
increases
were
found
in
Ottobratica
and
Peranzana
oils
extracted
at
30
°
C:
12.6%
and
25.5%
of
the
sum
of
lignans,
respectively.
The
genetic
origin
of
olives
affects
the
phenolic
concentration
of
fruit
but,
at
the
same
time,
shows
an
important
impact
on
the
absolute
activity
of
PPO
as
reported
in
various
papers
(Alagna
et
al.,
2012;
Garcia-Rodriguez,
Romero-Segura,
Sanz,
Sanchez-Ortiz,
&
Perez,
2011;
Garcia-Rodriguez
et
al.,
2015;
Goupy,
Fleuriet,
Amiot,
&
Macheix,
1991;
Migliorini
et
al.,
2012;
Sciancalepore,
1985;
Sciancalepore
&
Longone,
1984).
The
low
PPO
activity
of
cv.
Cora-
tina
could
explain
the
lower
impact
of
the
CT
process
in
the
pheno-
lic
concentration
of
oil
extracted
from
this
cultivar,
compared
to
the
others
(Goupy
et
al.,
1991;
Taticchi
et
al.,
2013).
The
CT
was
also
studied
in
an
attempt
to
control
the
lipoxyge-
nase
(LOX)
pathway.
In
fact,
as
described
in
other
previous
works
(Garrido-Delgado
et
al.,
2015;
Selvaggini
et
al.,
2014;
Taticchi,
Esposto,
&
Servili,
2014),
the
high
temperatures
(over
30
°
C)
reduce
the
formation
of
C6
aldehydes
and
esters
responsible,
respectively,
for
fresh
cut
grass
and
fruity
sensory
notes,
whereas
they
appear
to
increase
the
alcohol
production
responsible
for
ripe
fruitiness.
The
rapid,
olive
paste
cooling
showed
quantitative
and
qualitative
modifications
of
volatile
compounds
of
EVOOs,
which
appear
to
be
strongly
connected
to
the
olive
cultivars
and
the
effects
on
the
activity
level
of
the
different
enzymes
belonging
to
the
LOX
pathway.
A
variation
in
the
aldehyde
concentration
in
the
EVOOs,
obtained
from
the
cv.
Coratina,
was
not
detected,
whereas
alcohols
increased
in
the
CT
oils
malaxed
at
25
°
C
and
30
°
C,
compared
to
the
control,
with
an
increase
of
18.7%
and
54.3%
of
the
sum
of
sat-
urated
and
unsaturated
alcohols,
respectively.
The
percentage
increases
for
both
temperatures
of
malaxation
were
mainly
due
to
a
rise
in
1-hexanol
and
(E)-2-hexen-1
-ol,
probably
due
to
a
dif-
ferentiated
effect
of
the
cooling
process
on
the
thermal
stability
and
relative
activity
of
Coratina
enzymes
involved
in
the
release
of
these
volatile
compounds,
that
could
have
a
specific
response
to
the
rapid
reduction
of
temperature
at
15
°
C.
The
generally
very
low
concentration
of
esters
in
this
cultivar
was
reduced
in
both
EVOOs
malaxed
at
25
°
C
and
30
°
C
following
the
CT
of
the
olive
paste
(Table
3).
This
behaviour
could
be
due
to
a
block
of
the
lipoxygenase
pathway,
characterised
by
a
strong
inhibition
of
alco-
hol
acetyltransferase
activity
of
cv.
Coratina
at
a
low
temperature,
obtained
by
the
rapid
cooling
conditioning
of
the
olive
paste.
Insignificant
differences
in
the
aldehyde
concentration
was
also
observed
for
the
cv.
Ottobratica,
whereas
the
alcohols
showed
a
considerable
reduction
at
both
temperatures
tested:
46.2%
and
15.4%
of
the
sum
of
saturated
and
unsaturated
alcohols,
Table
4
Evaluation
of
phenolic
compounds
(mg/kg)
of
EVOOs
Control,
CT
and
CT-DI
of
cv.
Ottobratica
malaxed
at
25
°C.'
Control
Cr
cr-DI
3,4-DHPEA
20.9
(0.2)a
22.8
(0.1)b
26.9
(03)c
p-HPEA
17.8
(0.05)a
18.6
(0.2)b
19.9
(0.4)c
3,4-DHPEA-EDA
199.7
(1.8)a
244.1
(2.5)b
2283
(4.4)c
p-HPEA-EDA
47.8
(0.2)a
48.1
(0.9)a
47.2
(2.4)a
3,4-DHPEA-EA
76.7
(1.1)a
84.2
(1.0)a
95.9
(4.8)b
Ligstroside
aglycon
7.6
(0.09)a
7.8
(0.1)a
7.7
(0.4)a
(+)-1-Acetoxypinoresinol
22.1
(0.2)a
22.9
(0.9)ab
24.7
(1.2)b
(+)-Pinoresinol
39.7
(1.1)a
42.2
(1.4)a
43.4
(2.2)a
Total
phenols
4323
(2.4)a
490.7
(33)b
494.1
(7.4)b
Data
are
the
mean
of
three
independent
experiments
analyzed
twice,
and
the
standard
deviation
is
reported
in
brackets.
Values
with
the
same
letters
in
each
row
(a-c)
are
not
significantly
different
(p
<
0.05).
b
cr
=
cooling
treatment.
c
cr-DI
=
cooling
tretment
-
dry
ice.
Table
5
Evaluation
of
volatile
composition
(µg/kg)
of
EVOOs
Control,
CT
and
CT-DI
of
cv.
Ottobratica
malaxed
at
25
°C.
Control
CT
CT-DI
Aldehydes
(E)-2-Pentenal
98
(5)a
110
(1)b
90
(1)c
Hexanal
674
(3)a
668
(5)a
693
(1)b
(E)-2-Hexenal
100577
(1222)a
109890
(2455)b
106111
(3377)ab
(E,E)-2,4-Hexadienal
1499
(19)a
1555
(1)b
1919
(6)c
2,4-hexadienal
(i)
964
(32)a
975
(25)a
925
(50)a
Alcohols
1-Penten-3-ol
532
(22)a
529
(17)a
537
(6)a
(E)-2-Penten-l-ol
429
(9)a
439
(12)a
397
(14)b
1-Hexanol
5063
(28)a
2058
(34)b
2924
(12)c
(Z)-3-Hexen-l-ol
1854
(9)a
1462
(9)b
1398
(1)c
(E)-2-Hexen-l-ol
5979
(84)a
2897
(63)b
4563
(52)c
Esters
Hexyl
acetate
89
(3)a
119
(7)b
129
(1)c
(Z)-3-Hexenyl
acetate
207
(2)a
269
(3)b
244
(2)c
Data
are
the
mean
of
three
independent
experiments
analyzed
twice,
and
the
standard
deviation
is
reported
in
brackets.
Values
with
the
same
letters
in
each
row
(a-c)
are
not
significantly
different
(p
<
0.05).
b
c'
=
cooling
treatment.
c
cr-DI
=
cooling
tretment
-
dry
ice.
112
G.
Veneziani
et
al./
Food
Chemistry
221
(2017)
107-113
respectively,
for
the
CT
oils
extracted
at
25
°C
and
30
°C
compared
to
the
control
samples.
As
regards
the
concentration
of
esters,
a
sig-
nificant
variation
was
found
in
the
CT
oils,
characterised
by
an
increase
in
the
sum
of
esters
of
36.1%
for
the
oil
extracted
at
25
°C
and
48.5%
for
the
other
oil
extracted
at
the
highest
tempera-
ture
of
malaxation
(Table
3).
As
regards
the
cv.
Peranzana,
the
data
showed
an
overall
reduction
in
alcohols,
which
was
more
evident
for
the
CT
oil
extracted
at
30
°C,
with
a
42.6%
decrease
in
the
sum
of
saturated
and
unsaturated
alcohols.
A
high
variability
was
also
observed
for
esters,
particularly
abundant
in
this
Apulian
cul-
tivar
(Leone
et
al.,
2015;
Selvaggini
et
al.,
2014;
Servili
et
al.,
2015;
Veneziani
et
al.,
2015),
with
an
increase
of
116.6%
and
33.1%,
respectively,
for
the
sample
obtained
at
the
lowest
and
at
the
high-
est
temperatures
tested.
The
Peranzana
oils
also
showed
no
signif-
icant
modification
in
the
sum
of
saturated
and
unsaturated
aldehydes
compared
to
the
control
samples
(Table
3).
The
techno-
logical
innovation
introduced
in
the
mechanical
extraction
process
of
the
oil
revealed
different
results
of
volatile
composition.
It
high-
lighted
a
large
cultivar-dependency,
even
though
the
rapid
cooling
conditioning
of
olive
paste
showed
a
low
variability
in
the
sum
of
saturated
and
unsaturated
aldehydes
of
all
EVOOs
extracted
from
the
three
Italian
olive
cultivars,
with
a
range
between
-0.1%
and
+3.7%.
The
cv.
Coratina
malaxed
at
30
°C
had
the
maximum
value
and
the
cv.
Peranzana
showed
the
minimum
value,
when
the
oil
was
also
extracted
at
30
°C
of
malaxation.
The
only
exception
was
represented
by
the
oil
extracted
at
25
°C
from
olives
of
cv.
Ottobratica,
which
showed
an
increase
of
12.9%,
due
to
a
higher
value
of
(E)-2-hexenal.
The
experiments
performed
using
dry
ice
to
cool
the
olives
directly
during
crushing
(CT-DI)
was
carried
out
to
compare
the
impact
of
cooling
treatment
on
the
quality
of
EVO0
during
and
post
crushing.
Table
4
shows
how
the
phenolic
fraction
of
CT-DI
oil
maintained
the
same
increasing
trend
of
the
CT
test
compared
to
the
control,
and
did
not
show
significant
percentage
variations
compared
to
CT
oil.
The
volatile
composition
of
CT-DI
oil
showed
similar
changes
than
CT
sample
compared
to
control
oil
(Table
5),
even
though
the
increase
in
the
sum
of
saturated
and
unsaturated
aldehydes
was
more
limited
in
CT-DI
oil
than
CT
oil,
due
to
the
lower
amount
of (E)-2-hexenal.
On
the
contrary,
higher
values
of
1-hexanol
and
(E)-2-hexen-1
-ol
were
responsible
for
a
more
lim-
ited
reduction
in
the
sum
of
saturated
and
unsaturated
alcohols
of
CT-DI
oil
compared
to
the
control
sample.
The
cooling
treatment
is
a
thermal
conditioning
widely
used
in
the
food
and
agro
industry,
but
this
was
the
first
time
it
had
been
applied
to
the
mechanical
extraction
process
of
olive
oil.
For
decades
the
researchers
have,
in
fact
focused
their
technological
studies
on
the
heating
of
olive
paste
to
improve
the
oil
yield
and
the
quality
of
the
product.
Nevertheless,
the
rapid
cooling
of
olive
paste
at
15
°C
showed
very
interesting
results,
with
a
positive
impact
on
EVO0
quality,
mainly
related
to
the
phenolic
composi-
tion.
The
CT
determined
an
increase
in
phenolic
fractions
for
all
the
cultivars
and
at
both
temperatures
of
malaxation
tested,
even
though
the
percentage
increase
is,
however,
linked
to
the
different
cultivar
studied.
The
major
amounts
of
phenolic
compounds
are
due
to
a
thermal
inhibition
of
the
main
enzymes
responsible
for
a
process
of
degradation
during
the
first
phase
of
olive
oil
produc-
tion.
Even
in
this
experiment,
the
volatile
composition,
highlighted
a
strictly
cultivar-dependent
variability
(Esposto
et
al.,
2013;
Inarejos-Garcia,
Fregapane,
&
Desamparados
Salvador,
2011;
Issaoui
et
al.,
2015;
Veneziani
et
al.,
2015;),
with
specific
responses
of
the
enzymes
of
the
LOX
pathway
of
each
different
cultivar
(Chiappetta,
Benincasa,
&
Muzzalupo,
2015;
Padilla,
Hernandez,
Sanz,
&
Martinez-Rivas,
2009,
2012;
Padilla,
Martinez-Rivas,
Perez,
&
Sanz,
2012;
Patui
et
al.,
2010;
Sanchez-Ortiz,
Romero-
Segura,
Sanz,
&
Perez,
2012)
to
the
rapid
cooling
treatment
of
olive
paste.
Acknowledgements
This
study
was
kindly
supported
by
Alfa
Laval
SpA
(Tavarnelle
Val
di
Pesa,
Florence,
Italy)
and
Ministero
dell'Istruzione,
dell'Universita
e
della
Ricerca
(MIUR),
Italy
(Project
CLUSTER
CL.A.N.-Agrifood
AREA1-
Nutrizione
e
Salute
Pros.IT
(CTN01_00230_413096)).
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