DEGREENING AND CITRUS FRUIT QUALITY Fruit Crops

DEGREENING AND CITRUS
W. F.
Fruit
Crops
University
Citrus
Research
700
FRUIT QUALITY
Wardowski
Extension
of
Specialist
Floridat
IFAS
and Education
Experiment
Lake Alfred,
Station
FL
Center
Road
33850
2
DEGRERNING AND CITRUS
Table
of
Contents
Introduction
Degreening
Keeping
Conditions
Records
and Measuring
Lemons
Ethrel
(Ethephon)
Color
Wound Healing
Dehydration
and Humidification
Decay
Fi~ure8
References
and
Tables
FRUIT QUALITY
Conditions
3
Introduction
The need for
climate.
Citrus
different
from
Florida
and
subtropical
humid
fruits
those
Mexico
It
is
different
fruit
or
high
Citrus
2:reen
to
the
have
the
attempting
color
in
scarred
(thus
the
content.
citrus
fruit
from
why California
and why Florida
grows
markets
about
have
with
distinct
degreening),
different
thin
the
climates
mainly
15% fresh
the
a tendency
Understanding
a crop
grown
and market
fruit
for
and
in
Figure
citrus
subtroplcs
for
China,
grown
in
in
produce
need
juice
fruit
shown
differences
peel,
very
humid
of
are
the
and hi~h
between
predominately
to
grown
are
by
Brazil,
characteristics
understand
and
influenced
climates.
climates
fruits
greatly
climates
desert
desert
bef6re
understand
market
arid
climates
su.~ar.
differences
to
in
to
even
arid
Some of
is
semitropical
considered
blemished
or
fruit
in
in
important
juice.
pale
peel.
grown
are
and
characteristics:
for
citrus
grown
climates.
subtropic
(l3).
In
degreening
the
makes
it
easy
fresh
fruit
85% processed
citrus
Degreening is a very
great
deal,
more
detailed
the
recommended
research
quality
in
decay.
These
several
effects
conditions-
is
from
In nature, citrus
is
ways:
degreening
removed
complex
the
conditions
color,
vary
Degreening
to
allow
(10).
Although
may change
completed.
will
peel
sub.1ect
Degreening
wound
with
healing,
the
the
future
can affect
fruit
and
condition,
a process
by which
yellow
orange
or
as
fruit
dehydration,
variety,
is
in
we know a
and
green
color
degreens when the weather is cool enough.
color
to
In
show.
4
packin~hou8est
degreening
season,
fruit
season
Althou~h
than
with
is
degreening
lemons)
is
easily
the
ethylene
end
aid
of
of
the
(27).
Apparently,
proportion
of
a to ethylene
conditions
are
(23,
28,
30)
for
Ethylene:
5 ppm
Air
10 cfm
Circulation:
Fresh
Air:
These
conditions
seem simple.
and maintained.
as more
to be 5 to
accurately
maintain
5 ppm.
ethylene
Although
ethylene
burn")
10 ppm
at
the end of
is
more
(20).
Florida
citrus
levels
(17).
18).
Florida
field
pallet
box
one
change
air
per
they
was done
level
has
levels
as 20.000
capacity
have
for
the
fast
of
narrowed
or
are not easily
and as
The ability
boXt
hour
recommendations
ethylene
as high
humidity
per
ethylene
levels
high
per
However,
research
The optimum
determined
("gas
much more
(28-290C)
100 cfm
Degreening
detailed
improved.
and decay,
the
simple:
90-96% relative
an exact
in
b which
degreenln~
in
is
chlorophyll
Humidity:
methods
gas
early
season
82-8S0F
years
ethylene
degreened
Temperature:
achieved
injury
the
Conditions
Ideal
(except
at
a larger
chlorophyll
with
citrus
regreens
degreen
there
Degreening
accomplished
which
to
resistant
the
is
rooms.
difficult
the
it
evolved
over
equipment
and
degreening
citrus
the
to
recommendation
increase
ppm will
packers
was
respiration
not
cause pee
to
5
The
addition
Department
this
rule
This
is
is
that
recommended,
not
little
the
large
numbers
kept
for
is
part
is
Florida
The
reason
for
at 85 0 F.
fastest
Bulletin
by Grierson
keeping
with
for
and any
other
and
keeping
the
or
air
change
per
hour.
air
change
per
hour
low
as
/2
in
use
in
Spain
to
(personal
Most
result
because
tomato
degreening
a carbon
may be in
rooms
is
communication,
Florida
in
In
dioxide
dual
are
build
purpose
traditionally
Conditions
is
an important,
blank
spaces
level
date,
room
each
each
keepin~
4).
fruit
be several
day.
work
shift.
boring
The
task.
wet
top
of
variety,
important
to
your
varieties
A separate
One person
team.
but
temperature,
number,
would
section.
for
(Figure
information
leaving
during
record
one
Exceptions
and Measuring
room
is
no ventilation
a place
each
of
2).
classic
Valencia).
rooms
or
arriving
record
(Figure
as
(6).
modern rooms there
for
85 0 F by
to
citrus
a 1960
enough
and ethylene
have
number,
tight
a form
temperature,
is
Hermanos,
record
have
lot
(6
degreening
Routine
should
in
exchange
rate
sealed
Records
to
20-31
Florida
3)
air
coloring
with
best
this
Pascual
slower
Keeping
fresh
and Israel
tomato/citrus
built
(Figure
and
Sanchez,
up and
of
limited
(12).
(27)
are
is
Chapter
degreening
suRgested
Australia
heat
Rules,
illustrated
Our
rooms
artificial
of Citrus
and Newhall
I.
of
should
Usually
page
It
is
bulb
the
form
grower
or
records.
With
and lot
needs
to
be
be made responsible
the night
watchman
6
Wet and dry
position
used
of
to
strong
measure
the
wet
the
lower
bulb
air
the
air
high
humidity
checked
The
relative
5)
flow)
fresh
air
as
changing
on the
will
there
are
fans
or
motors,
to
pressure
Velometers
accordingly.
cooling
systems.
Center,
and
the
water
bulb
set
at
no chan~es
the
the
the
fresh
fan
and
air
the
air
one
at
the
Citrus
conditioni~
the
at 85 0 Fa
0
time
and a false
can
be
operated
fan
the
is
room
as expanding
will
the
remain
throu~h
room,
constant.
an outside
opening
flow
Research
contractors
Too
movement
battery
vent
from
to 2 F
readin~s
(sling
air
be
(23,30,31).
unit
the
can
difference
evaporation
such
fresh
(14)
evaporation
~reater
are used to measure air
We have
larger
less
usually
etc.,
of
the
psychrometer
measure
side
minute
Water
psychrometer
a portable
as
used
per
be allowed
and dry
a sling
lo~
--
should
in
The wet
or
feet
placed
When degreening
result
with
500
readin~
that
is
is
low
all
exchan~e
the
A velometer
is
(hygrometers)
and humidity.
a lower
readin~.
air
over
humidity.
movement
and
movement
in
occasionally
provides
units
temperature
(Fip;ure
little
thermometer
reslllts
the
difference
built
bulb
is
vent
adjusted
in heating
and
and
Education
are
ikely
to
use
them.
Lemons
Lemons
degreening
ethylene
conditions
have
already
conditions.
at
60oF
resulted
for
been
mentioned
Lemons
up to
traditionally
3 weeks
in excessive
(26).
decay.
as an exception
were
Normal
to
cured
citrus
Ethephon (Ethrel
normal
with
"zero'
degreening
was shown
7
to
reduce
the
decay
(29).
levels
of
degreening
time
Finally,
the use of
ethylene
(0.5
to
the 2 to 3 weeks time
Ethrel
for
lemons
with
reasonable
predegreening
1 ppm)
was shown
to 2 to J days
safety
fungicides
to
from
and
be effective.
reducing
(1
(Ethephon)
Ethrel
is
a chemical
can be applied
about
the
12.000
known
same effect
ppm)
to
be f()re
and
or after
over
low amounts of ethylene
harvest.
ti~8
degreening
(11.
releases
a wide
immersion
enhance
grapefruit
which
range
(1
of
Ethrel
of
to
was reported
(16.
lemons
to
concentrations
10 minutes)
and
have
(1000
to
Ethrel
11).
29) oranges
(11)
is
and
16).
Color
Maturity
growers
color
standards
develop
break.
attempts
to
define
of
it
color
color
is
that
approximates
the
determined
standard
degreening
is
to
show.
to
rule.
when
break.
break
is
color
color
is
Although
numbers for
remove
the
green
called
they
Department
has adequate
interpretation
somethin~
blindness
The Florida
determination
degreened
color
include
of
try
in
presently:
color
color
Rule
and
important.
break.
bravely
the practical
the
fruit
for
this
be
liberal
~thod
are
The obvious
the
can
this
there
and allow
adequate
20-34
Florida
The reason
subjective,
break.
determine
when
break.
is
to
Citrus
However,
it
color
no simply
reason
yellow
or
for
orange
8
Varietal
color
varieties
orange
holdin~
citrus
was
and red
at
on chlorophyll
achieved
at
slov
for
reported
pigments
various
to
77
0
that
various
for
can be increased
F and
carotenoid
com8ercial
and
(31)
temperatures
59
Washing reduces
days.
too
dependent
Wheaton and Stewart
pigments.
color
is
10
synthesis
certain
after
and ethylene
1 to
carotenoid
ppm
harvest
levels.
The best
ethylene
(15)
by
in
3 to
8
and the proceR8
s
application.
Wound Healing
Very
high
humidities
development
during
lignification
portion
of
the
healing
peel).
96% have
This
of
small
Wound healing
Severe
oleocellosls
been
shown
to
was explained
injuries
in
occurs
only
(oil
spotting)
is
harvested
reduce
(2.
the
at
8O1d
7) as
flavedo
hiRh
{colored
relative
wss not
overcome
looses
8Oisture
by
healing.
Dehydration
and
From
the
no chance
to
degreening
breakdown
the
90 to
degreening.
~ound
humiditieswound
of
result
conditions
achieve.
(sometimes
Hu8idification
instant
citrus
replenish
fruit
the
supply.
are needed to reduce
of
oranges
of
(22)
earlier
is
High
moisture
relative
~isture
usually
first
loss.
Of the
humidity
is
Stem-end
seen
above,
high
Humidity
can
be added
by stea8
which
by high
pressure
water.
needed).
humidities
108..
listed
not
it
the
in
five
the
during
rind
markets,
but
degreening
MOst difficult
also
with
adds
and by air
to
heat
81st
is
9
systeas
(24).
Air
Florida
citrua
degreening
used 8ucessfully
have
mist
in
a relatively
citrus
(12)
the
8Odern
movement
in
drys
fruit
wet
season,
dry
deRreening
wooden
pallet
of
humidity.
the
to
has
wet
in
can
that
the
been
Sanchez),
but
tried
in
not
of
moisture
pallet
from
he helpful
in
high
in
air
quickly
the
boxes
Florida
be put
the
circulation
At
in
have
should
room.
absorb
to
been
fruit
air
wettinR
proven
I.
because
Hi~h
used
nozzles
not
important
huaddity
so
season
that
9).
boxes
atomizin~
and have
no longer
(8.
common type
communication,
cost
rooms
8Ost
Sonic
The idea
is
adda
room
beginning
initial
and
the
(personal
rooms.
rooms
are
rOO88.
Spain
hi~h
degreening
degreening
systems
start
of
the
the
at
the
some cases.
Decay
The 8OSt
concise
statement
regardln~
decay was by Andy HcCornack, "Ethylene
state8ent
to
the
says
it
Larger
all.
same amount
of
the
effect
increases
of
will
increase
or longer
certain
on
That
decay."
amounts of ethylene.
ethylene
degreening
kinds
of
exposure
decay
in
citrus.
Ste.-end
rot
natalensis,
is
Anthracnose
infection
is
occurs
increased
The effect
(3,21).
disease
which
is
of
also
related
in
by exposing
the season,
the
fruit
excessive
ethylene
is
increased
by ethylene
common on Robinson
is
early
to peel
tangerines
color
(4,
and
5).
Diplodia
0
to ethylene
shown
during
the
Yellow
in
st 85 F
Table
degreening.
severity
fruit
of
'n1is
the
are easily
~
10
infected
while
relationship
groups
dark
is
will
Table 1.
orange
fruit
so consistent
frequently
Effects
that
sort
of
on decay
two
are
more resistant.
color
sortin~
anthracnose
into
concentrations
4 weeks
after
of
picking
color
tangerines
three
into
levels
ethylene
of
during
(adopted
z
TreatlEnt
This
from
-~C-
severity.
degreening
21).
ValenciaY
Hamlin
three
TemplesYx
~
.--% decay w
Not
Degreened
a
6.5 a
59.9 a
4 ppm Ethylene
23.6 ab
11.1 a
60.5 a
50 ppm Ethylene
32.5
21.1 b
81.3 b
z
Average
Y Average
x
w
17.0
of
of
b
3 expe~iments.
4 experiments.
Freeze i n.iured.
Data
followed
by
probability
level
Washin~
(19.25)
before
and
degreening
offset
the
by
A more
of
longer
and
detailed
E. Brown 1s found
rot
(15)
in
in
each
column
do not
differ
at
a
5%.
degreening
stem-end
process
same letter
has
(25).
so
been
This
that
the
poorer
degreening.
discussion
of
the decay
reported
process
advantage
stem-end
control
rot
section
to
also
of
slows
reducing
and
of
reduce
anthracnose
the
decay
anthracnose
these
is
by G.
proceedings
1
l.eferencea
1.
Barmore,
C. R., T. A. Wheaton and A. A. McCornack.
Ethylene
degreenJng
of
'Bearss'
1976
HortScience
le80ns.
11(6):588-590.
2.
Brown.
Phytopathology
oranges.
3.
4.
Development
1973.
G. Eldon.
fruit
increased
Proc.
Fla.
Brown,
G. Eldon
ethylene,
Hort.
color,
mold
in
de~reened
rot,
a decay
treateent
of
and
citrus
its
control
Soc. 99:105-108.
and
tangerines
stem-end
degreening
and Charles
fruit
'Robinson'
Diplodia
by ethylene
State
green
63(9):1104-1107
1986.
Brown. G. E.
of
to
1976.
R. Barmore.
fungicides
The effect
on susceptibility
Proc.
anthracnose.
Pla.
of
of
State
Kort.
89:198-200
5.
Brown,
G. Eldon
ethylene
of
and Charles
susceptibility
Phytopathology
6.
7.
tangerines
The degreening
of
Div.
of
Center.
Ismail,
H. A. and G. E. Brown. 1975.
healing
of
Sci.
W.
Grierson,
W.
to
of
anthracno8e.
in
Israel.
The
Publications.
72 pages.
Valencia
Hort.
fruit
Scientific
Volcani
Grierson,
128.
citrus
Publication
Packinghouse
9.
Robinson
Special
Soc.
8.
of
'Dte effect
67(1):120-123.
1979.
Cohen E.
1977.
R. Barmore.
orange
peel
under
Phenolic
high
content
humidity.
during
J.
!mer.
60:248-251.
1966.
Newsletter
1972.
Packinghouse
Pallet
box
degreening
rooms.
Univ.
of
Fla.
No. 5:1-5.
Continuous
Newsletter
vs.
No.
batch
45:1-4
degreening.
Univ.
of
12
Grierson,
W., E. Cohen and H. Kitagawa.
Fresh
Citrus
eds.
Avi
for
Co..
postharvest
degreening
Sci.
Grierson,
Univ.
fruits.
Grierson.
W. and
fruits,
S. Nagy and W. Grierson
CT.
253-274.
1972.
and M. F. Oberbacher.
of
In
Degreening.
oranges
Ethephon
J. Aller.
and grapefruit.
97(4):541-544
W. and W. F.
citrus
Westport,
W., F. H. Ismail
Soc. Rort.
13.
W. F. Wardowski,
Fruits.
Publishing
Grierson,
1986.
juices
S.
Fla.
V.
1960.
Newhall.
Agr.
Ting.
Expt.
Sta.
1978.
and beverages.
Degreening
Bull.
Quality
Proc.
Int.
of
Florida
620.
80 pages.
standards
for
Soc.
Citriculture
Humidity
in
citrus
1:21-27.
14.
5.
Grierson,
horticulture.
RortScience
Jahn. Otto L.
1975.
chlorophyll
Soc.
16.
10(4):356-360.
Effect
and carotenoid
Hart.
Sci.
and
of washing
changes
'Haalin'
during
orange
on
J. ADler
degeening.
100(5):586-588.
Jahn. Otto L.
ethephon
1975.
W. and W. F. Wardowskl.
1976.
Degreening
J.
te8perature.
of waxed citrus
Aaer.
Soc.
fruit
Hort.
with
Sci
101(5):597-599.
Jahn,
of
o. L.,
citrus
Otto
Degreening
te.perature.
Amer.
fruits
J.
ethylene.
Jahn,
W. G. Chace and R. H. Cubbedge.
Soc.
in
Amer.
L.,
response
Soc. Kort.
W. G. Chace,
response
of
ethylene
Hort.
Sci.
to
varying
Sci.
Jr.
'Hamlin'
levels
of
Degreening
oxygen
and
94(2):123-125.
1973.
and R. H. Cubbedge.
oranges
concentration.
98(2):177-181.
1969.
in
relation
and fruit
to
aaturity.
J.
13
19.
o. L.t R. H. Cubbedge and
Jahnt
washing
sequence
citrus
20.
fruits.
on the degreening
Proc.
Fla.
State
Jabot o. L. and R. Young.
and
the
a/b
J. J. S800t.
ratio
response
Hort.
duriDR
color
Effect
of
ethylene
Proc
Fla.
State
Effect.
and decay of
Soc.
Changes
1976.
1970.
of
SO8e
83:217-221.
in
chlorophyll
develop8ent.
J.
a.
A8er.
Soc.
b
Hort.
Sci.l0l(4):416-418.
21.
22.
KcCornack,
A. A.
1971.
of
citrus
fruit.
Florida
McCornackt
A. A. and W. Grieraon.
control
rind
of
Service,
23.
Univ.
McCornack,
citrus
fruit:
Raynor.
of
25.
and W. F.
J.
and
27.
J.
and C.
F.
by
Hort.
during
Extension
Degreening
Proc.
Int.
Cold
water
degreening.
Proc.
Melvin.
1912.
of
ti8e
of
washing
Decay
Florida
Soc.
mist
Fla.
State
citrus
hoc
Soc. 85:235-238.
in
Florida.
184.
Tugwell,
8. L. and K. J.
degreening
degreened
and TBZ application.
D. P. H. and W. F. Wardowski.
utilization
Horticulture
1977.
1979.
Wardowski.
Bulletin
and
for
92:189-192.
State
TUcker,
measures
286
and physiology.
citrus
as affected
Fla.
26.
of
Soc.
fruit
Practical
84:270-272.
:211-215.
Art
Smoot.
on decay
Soc.
Agricultllral
oraltges.
Circular
procedures
humidification
Hort.
FL.
of
Hort.
1965.
A. A. and W. F. Wardowski.
Cltrlculture
24.
breakdown
degreening
IFAS,
1973.
Unive
of
Le~n
Flae,
production
Extension
23 pages.
of
Notes.
fruit.
1987.
Gillespie.
Dept.
14 pages
of
Agriculture,
Controlled
ripening
South Australia
14
28.
29.
Wardowski,
W. F.
Newsletter
No.
Wardowski,
W. F.,
1974.
CurinR
Hort.
30.
Univ.
Degreening.
of
Fla.
Packinghouse
141:2-3.
of
C.
R.
Florida
Barmore,
T.
lemons
with
S.
Smith
ethephon.
and
C. W. DuBois.
Proc.
Fla.
State
Soc. 87:216-218
W. F. and A. A. McCornack.
Wardowski,
Recommendations
Extension
Service
Wardowski,
Fla.
1985.
for
degreening
Circular
Florida
Degreening
room
Packinghouse
Newsletter
No. 103:3
Wheaton,
T. A. and Ivan
Stewart.
ethylene
concentrations
for
pigments
in
J.
fresh
citrus
fruit.
IFAS
389
W. F.
citrus.
1972,1979.
Amer.
humidity
1973.
postharvest
Soc.
Hort.
measurement.
Oniy.
Optimum temperature
development
Sci.
of
of
and
carotenoid
98(4):337-340.
15
Figure1.
Effects of climatic
(adopted fran 13).
extremes on citrus
fruit
quality
16
Department
of
Chapter
20-31
Citrus
Page 1
CHAPTER 20-31
COLCltIR» ROOHHETHmS Arm PRAcrICES
20-31.001
20-31.002
20-31.003
20-31.001
Certain
Heating Prohibited
Air Circulation
Maximum T.mperature
Certain
Heatina
Prmibited:
No kerosene
or other
ti.-operated
inside,
or within
15 feet
of,
any color
citrus
fruits
are being
degreened.
gas-generating
ins-room
or
heater
enclosure
shall
where
Specific Authority: 601.10(1),(7), F.S. LawImplemented: 601.10(7), F.S. History: Foo.er1y
105-1.13(1)1 R8Y18ed1/1/751 Previously numbered 20-31.01.
20-31.003
MaxiTe..rature:
tainirigc1tru8
fruit
that
the temperature
when the added heat
humidity.
11\e temperature
of the
co10rlng-ro~
or
enc108ure
conin the proces8
of being
degreened.
aha11 be so controlled
shall
not exceed
8S8F. due to application
of heat.
except
comes from
steam re1ea8ed
into
the atmosphere
to increase
Specific
Authority:
601.10(1),(7),
F.S.
Law Imp1~ed:
10S-1.13(3);
Revised 1/1/7S; Prev1ous1y numbered 20-31.03.
Figure 2.
Florida
Department
of
Citrus
Rules
601.10(7),
pertaining
to
F.S.
History:
degreening.
Fo~r1y
17
Figure 3.
Effect of temperature
oranges (12).
on rate
of degreening
of Hamlin
19
WET / DRY BULB SPREAD
Figure
5.
Temperature
0
at 80
500 to
readings
0
to 90 F (26.7
1000 feet
per
0
for
wet
and
0
dry
to 32.2 C) dry
minute
air
flow
JWR
bulb
thermometers
bulb
over
readings
the wet
and
bulb
(31).