Increased olive oil yield and quality in Montenegrin cv Zutica by Bactrocera oleae Gmel. (Diptera Tephritidae) control and improved harvest techniques


Lazović, B.; Adakalić, M.; Perović, T.; Hrnčić, S.; Pucci, C.; Terrosi, A.; Spanedda, A.F.

Comptes Rendus de la Réunion 30(9): 301-305

2007


The present inquiry represents the basis for wider research into the qualitative and quantitative characterization of the typical olive oil of Montenegro. In the considered biotope the 65% of plants is composed of cv Žutica. The key insect is B. oleae, which is, in some years, able to nullify quantitatively the entire production because of the olives dropping off the trees. However the entire production is usually harvested and the product is the clear oil, both because of the infestation and elevated temperature and the long storage periods of olive that cause a remarkable increase in degrees of acidity. The work, carried out in 2004, consisted of studying the inolation on weekly samples of healthy olives harvested from the canopy and processed for olive oil extraction after 24-48 hours. This has allowed us to identify that the right moment for harvest is the third week of October. Finally the qualitative Analysiss of the oil drawn from the plant are presented in comparison to the qualitative characteristics of the output usually obtained by Montenegrin olive-growers after different stock periods. The results obtained represent the first and basic stage for the realization of research projects aimed to improve the techniques of production and protection of oil yield.

Integrated
Protection
of
Olive
Crops
10BCIwprs
Bull.
30(9),
2007
pp.
301-305
Increased
olive
oil
yield
and
quality
in
Montenegrin
cv
kutica
by
Bactrocera
oleae
Gmel.
(Diptera
Tephritidae)
control
and
improved
harvest
techniques
Biljana
Lazovie
1
,
Mirjana
Adakalie
1
,
Tatjana
Perovie
1
,
Snjeiana
Hrne'ie
2
,
Claudio
Pucci
3
,
Alessandra
Terrosi
3
,
Antonio
Franco
Spanedda
3
1
Biotechnical
Institute,
Center
for
Subtropical
Cultures,
BjeliR
bb,
85000
Bar,
Montenegro,
SCG
2
Biotechnical
Institute,
Center
for
Plant
Protection,
Kralja
Nikole
bb,
81000
Podgorica,
Montenegro,
SCG
University
degli
Studi
della
Tuscia-
Dipartimento
di
Protezione
delle
Piante,
Via
S.
Camillo
de
Lellis.
01100
Viterbo
-
Italy
Abstract:
The
present
inquiry
represents
the
basis
for
wider
research
into
the
qualitative
and
quantitative
characterization
of
the
typical
olive
oil
of
Montenegro.
In
the
considered
biotope
the
65%
of
plants
is
composed
of
cv
Zutica.
The
key
insect
is
B.
oleae,
which
is,
in
some
years,
able
to
nullify
quantitatively
the
entire
production
because
of
the
olives
dropping
off
the
trees.
However
the
entire
production
is
usually
harvested
and
the
product
is
the
clear
oil,
both
because
of
the
infestation
and
elevated
temperature
and
the
long
storage
periods
of
olive
that
cause
a
remarkable
increase
in
degrees
of
acidity.
The
work,
carried
out
in
2004,
consisted
of
studying
the
inolation
on
weekly
samples
of
healthy
olives
harvested
from
the
canopy
and
processed
for
olive
oil
extraction
after
24-48
hours.
This
has
allowed
us
to
identify
that
the
right
moment
for
harvest
is
the
third
week
of
October.
Finally
the
qualitative
Analysiss
of
the
oil
drawn
from
the
plant
are
presented
in
comparison
to
the
qualitative
characteristics
of
the
output
usually
obtained
by
Montenegrin
olive-growers
after
different
stock
periods.
The
results
obtained
represent
the
first
and
basic
stage
for
the
realization
of
research
projects
aimed
to
improve
the
techniques
of
production
and
protection
of
oil
yield.
Key
words:
inolation
of
fruits,
fruit
growth,
storage,
fatty
acid,
2utica
Introduction
2utica
is
the
most
important
olive
cultivar
in
Montenegro.
It
predominates
in
olive
assortment
with
65%,
while
in
the
areas
of
Bar
and
Ulcinj
it
is
present
with
98%.
It
is
an
old
variety
with
some
example
2000
years
old,
'Velja
maslina'
in
Ivanoviei
near
Budva.
Zutica
is
a
good
cultivar
for
oil
production,
which
is
of
about
21%
in
the
fruit.
It
is
also
used
for
conservation
in
traditional
ways
as
green
and
black.
The
name
of
the
cultivar
comes
from
its
colour,
which
before
maturing
is
yellow.
Sloppy
terrains
and
poor
soils
characterize
the
conditions
for
olive
growing
in
Montenegro.
Traditional
ways
of
growing,
with
high
trees
rarely
pruned
and
tree
structure
that
does
not
allow
regular
application
of
agricultural
treatments,
cause
big
problem
for
harvesting.
B.
oleae
is
another
problem
and
in
some
years
affects
production
because
of
the
fruit
dropping.
Picking
the
fruits
from
the
ground
forms
part
of
the
harvest.
Nets
are
rarely
used
and
fruits
fall,
because
of
damage
or
maturity,
on
the
ground,
from
where
they
are
occasionally
collected.
Those
conditions
with
elevated
temperature
and
the
olives'
long
storage
periods
cause
a
remarkable
increase
in
degrees
of
acidity.
301
302
However,
Montenegro
is
directed
to
EU,
with
efforts
to
accept
and
to
follow
EU
rules,
so
the
good
quality
olive
oil
production
would
also
be
very
important
for
olive
development
aspects
and
from
an
economical
point
of
view
as
well.
Investigations
of
this
kind
have
not
be
conducted
in
Montenegro
before.
Olive
oil
was
determined
only
with
aim
to
characterize
some
varieties
of
interest
(Miranovic,
1971, 1979,
1994;
Lazovic,
2001).
This
work
represents
the
basis
for
wider
research
to
take
place
on
quantitative
and
qualitative
characterization
of
the
typical
olive
oil
of
Montenegro.
Material
and
methods
The
experimental
field
is
situated
in
the
city
of
Bar
8
m
above
sea
level
and
500
m
distant
from
the
sea.
An
old
orchard,
of
area
10
x
8m,
was
regenerated
in
the
60s
by
decapitation
on
the
level
of
trunk
neck
and
1
m
of
height
respectively.
In
the
80s
this
orchard
was
split
into
2
parts
by
street
construction.
One
part
of
the
orchard,
with
48
trees,
is
in
use
by
the
Center
for
Subtropical
Cultures,
while
the
other
part
with
51
trees
is
in
possession
of
the
School
of
Agriculture.
In
the
first
part,
used
by
the
Center,
trees
were
7-8
m
in
height
and
18
trees
were
severely
pruned
in
2004,
to
the
height
of
about
4
m.
Fertilization
was
done
with
1
kg/tree
of
NPK
(8:16:24)
by
the
end
of
January,
and
twice
with
0,5
kg/tree
of
nitrogen
in
March
and
May.
In
another
part
of
orchard
(School
of
Agric.)
trees
were
8-10
m
in
height
and
44
trees
were
severely
pruned
in
2003,
with
about
5
m
of
height
in
experimental
year.
No
irrigation
was
applied
and
orchard
soil
cover
maintenance
was
made
by
regular
grass
cutting.
For
determining
oil
increment
dynamics,
samples
of
healthy
fruit,
about
200
g,
were
taken
from
8
trees
from
the
middle
portion
and
all
sides
of
the
crown.
After
measuring
fresh
weight,
samples
were
dried
on
105
°C
to
the
constant
weight,
grounded
and
oil
was
extracted
by
Foss
let
(Soxlet
method).
At
harvesting
time
(26.10.)
one
sample
of
about
6
kg
of
fruits
was
taken,
divided
into
4
portions
and
from
each
portion
oil
was
extracted
at
laboratory
olive
mill
with
one
week
of
distance.
In
extracted
oil
free
acid,
peroxides
and
humidity
were
determined.
All
Analysiss
were
conducted
at
laboratories
of
the
Center
for
Subtropical
Cultures
in
Bar
Montenegro
and
at
the
University
of
Tuscia
in
Viterbo,
Italy.
Results
and
discussion
Fruits
of
cv
Zutica
were
characterized
as
small
(Miranovic,
1971,
1979)
to
the
middle
size
(Lazovic,
2001)
and
this
what
was
confirmed
with
those
investigations.
Fruit
growth
dynamics
presented
on
Figure
1,
shows
permanent
increment
tendency.
The
most
intensive
growth
was
in
more
than
one-month
period,
from
the
middle
of
September
to
last
week
of
October.
Average
fruit
volume
rose
for
1.5
g,
corresponding
to
about
40.98
%
of
their
weight
in
the
observed
period.
Average
fruit
ripening
of
cv
Zutica
is
in
the
beginning
of
November
(Lazovic,
2000),
and
from
the
Figure
1.
could
be
seen
that
fruit
volume
was
reaching
its
maximum
at
the
same
period
when
harvesting
was
done.
Proof
for
the
right
time
of
harvesting
we
also
achieved
by
following
the
increment
of
oil
dynamics
in
the
fruit
of
cv
Zutica,
presented
on
Figure
2.
Cv
Zutica
is
characterized
with
high
content
of
oil
in
the
fruit
of
about
21%
of
fresh
olives
(Miranovic,
1971, 1979,
1994;
Lazovic,
2001).
Oil
content
presented
on
dry
mass
showed
permanent
increment
during
two
months
of
observation.
Very
intensive
oil
increment
was
found
in
the
period
from
the
end
of
August,
later
than
in
findings
of
Tombesi
(1994),
to
the
middle
of
October.
The
most
intensive
oil
accumulation
was
during
20
days
of
September
.•-•
.,•--/
a a a
a)
a)
a)
Cl) Cl)
Cl)
z_r
,
02
Cal
Cal
measuring
dates
'
C)
O
6
of
of
4
.,-
.
4
et
Cal
o
il
con
ten
t
in
dry
mass
(
%)
60
50
40
30
20
10
0
303
and
in
first
half
of
October,
when
oil
quantity
increased
by
about
12%
per
period.
From
the
middle
of
October
there
was
very
low
increment
or
almost
stagnation
in
oil
accumulation.
Cv
Zutica
reached
its
maximum
of
fruit
inoliation
by
the
end
of
October
which
is
more
than
one
month
earlier
in
comparison
to
the
most
important Italian
olive
oil
varieties
(Cimato
et
al.,
1996),
but
in
accordance
with
the
results
of
the
maximal
oil
content
regarding
to
the
proper
harvesting
time
in
order
to
anticipate
olive
fly
attack
during
autumn
(Iarmotta
et
al.,
1996).
However,
this
experiment
should
be
followed
during
a
longer
period
of
time
and
in
different
areas
where
cv
Zutica
is
grown
to
conclude
that
the
early
maximal
inolation
is
the
property
of
the
cultivar.
4
3,5
im
3
c
.c
.
2
'
5
,
2)
2
,...
1,5
4--
1
0,5
0
24-Aug
7-Sep
21-Sep
5-Oct
measuring
dates
19-Oct
2-Nov
Figure
1.
Average
value
of
fruit
growth
dynamic
in
cv
Zutica
in
2004.
Figure
2.
Oil
content
increment
dynamic
in
fruits
of
cv
Zutica
in
2004.
Analysis
of
oil
extracted
from
collected
fruits.
Quality
parameters
in
olive
oil
extracted
in
one
week
periods,
from
fruit
collected
from
the
ground
are
presented
in
Figures
3
and
4.
Acidity
is
alteration
caused
by
olive
oil
hydrolysis
due
to
microbic,
enzymatic
or
microbic-hydric
action.
Microbes
growing
in
the
fruit
after
insect
attacks,
enzymatic
activities
such
of
lipase,
or
microbes
developing
in
presence
of
water
are
the
main
factors
for
increasing
acidity
(Michelakis,
1992).
Infestation
by
the
olive
fly
(B.
oleae)
is
a
major
cause
of
the
high
free
fatty
acids
(FFA)
content
in
olives.
Falling
from
the
trees
causes
bruises
of
the
olives,
which
together
with
long
storage
times
results
in
lipolysis
increasing
FFA
content
in
the
produced
oil
(Mulk
et
al.
2003).
304
14,00
12,00
c
10,00
c
o
0
8,00
to
7
5
a
6,00
R
z
>,
4,00
CU
F
i
2,00
0,00
27-Oct
3-Nov
10-Nov
measuring
dates
17-Nov
Figure
3.
Free
fatty
acid
content
in
oil
depends
on
the
length
of
time
the
fruits
are
stored
before
processing.
Our
results
confirm
previous
opinion
that
low
oil
quality
is
also
connected
with
the
technique
of
collecting
fruits
by
picking
from
the
ground.
Figure
3.
shows
increase
of
acidity
(expressed
as
oleic
acid
gr/100
g
of
oil),
with
time
of
storage.
Oil
obtained
from
fruits
one
day
after
collecting
had
acidity
less
than
2%,
while
after
one
week
it
was
about
6%,
results
obtained
by
analysing
oil
from
the
mills
in
Montenegro.
Our
results
differ
from
those
that
Conti
(1996)
obtained
from
the
fruits
after
2
weeks
of
storage,
where
the
higher
content
of
FFA
was
only
in
fruits
with
80%
of
infestation,
of
3,62,
while
in
our
samples
after
two
weeks
FFA
content
was
about
8.
Humidity
in
oils
(Figure
4)
obtained
from
those
samples
had
also
increasing
tendency
depending
on
the
fruit
storage
period.
0,40
0,35
.....
0,30
e
0,25
g
0,20
E
=
0,15
.c
0,10
0,05
0,00
27-Oct
3-Nov
10-Nov
17-Nov
measuring
dates
Figure
4.
Humidity
in
the
oil
of
cv
2utica
related
to
the
fruit
storage
period.
In
conclusion
it
can
be
said
that
for
improving
yield
and
olive
oil
quality
in
Montenegro
there
is
the
necessity
for
permanent
investigation
of
the
olive
oil
accumulation
in
the
fruit
regarding
proper
harvesting
times,
as
well
as
it
should
be
monitored
more
closely
qualitative
characteristics
of
olive
oil
in
the
relation
olive
fly
control,
harvesting
technique
and
stocking
period.
305
Aknowledgement
Those
investigations
and
Analysiss
were
conducted
thank
to
Prof.
Pucci
from
University
of
Study
of
Tuscia
who
helped
from
the
initiation
of
the
trial.
Thanks
also
to
his
collaborators
for
their
kind hospitality
in
the
laboratory
for
oil
Analysiss.
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