Relación entre pre y
post cosecha de la palta
Mary Lu Arpaia
University of California, Riverside
Quality
Quality and
and the
the Farmer
Farmer
What
What is
is under
under your
your control?
control?
Mary Lu Arpaia (September 2004)
1
The
The continuum
continuum
The most important thing to remember is
that there is a continuum from the grower
to the consumer
The steps in the continuum
Grower – Packer – Distribution - Consumer
Quality
Quality
The inherent properties
or attributes of a
product which
determines its relative
degree of excellence
Mary Lu Arpaia (September 2004)
2
Avocado Quality Attributes
Can mean many things, depending at what
point one is assessing the fruit
How do you as a grower perceive
“quality”?
Appearance Factors
4 Fruit size and shape, peel texture
4 Freedom from defects such as insect
scarring, wind damage, limb rub
Avocado
Avocado Quality
Quality Attributes
Attributes
cont.
cont.
Past the grower – the Packinghouse
4 Appearance to maximize packout of #1
fruit
4 “History of the grove” – STRESS,
LOCATION
4 Picking conditions – HOT, DRY vs WET
4 Delay from harvest to packer
4 Time of season - MATURITY
Mary Lu Arpaia (September 2004)
3
Avocado
Avocado Quality
Quality Attributes
Attributes
cont.
cont.
Past the grower – Distribution
4 Source of fruit at certain times of the
year - MATURITY
4 Product Uniformity
4 Ability to take ethylene in a predictable
manner
4 Have some storage life to adapt to
marketing situations
Avocado
Avocado Quality
Quality Attributes
Attributes
cont.
cont.
Past the grower – Consumer
4 Source of fruit? California vs other???
4 Product Uniformity
4 Ability to predict when ready to eat
4 Freedom from defects
4 Eating quality
Mary Lu Arpaia (September 2004)
4
Problems that
that you
you can
can find
find at
at
Problems
the retail
retail level
level with
with avocados
avocados
the
Body Rot
Stem End Rot
Mary Lu Arpaia (September 2004)
5
Postharvest
Postharvest Diseases
Diseases
Anthracnose
Body Rot
Dothiorella
Stem End Rot
Alternaria
Stem End Rot
Internal Bruising
Seed
cavity
Air pocket
Different symptoms
of internal bruising
Bruising underneath Peel
Mary Lu Arpaia (September 2004)
Bruising underneath Peel
Extending into the flesh
6
Peeling ease ranging from
extremely difficult (left) to
very easy (right)
Shriveling
Flesh/Mesocarp Discoloration
Preharvest
Preharvest
factors
factors
influencing
influencing
fruit quality
quality
fruit
Mary Lu Arpaia (September 2004)
7
Preharvest
Preharvest Factors
Factors
•
•
•
•
Environmental
• PGRs
Rootstock/Scion
• Irrigation
Spacing and Pruning • Nutrition
Pest Management
These factors are interactive and influence each other
How
How preharvest
preharvest factors
factors may
may
influence
influence fruit
fruit quality
quality
• Development and maturation
• Physical effects on quality and
packout
• Susceptibility to physiological
and pathological breakdown
Mary Lu Arpaia (September 2004)
8
Climate
Climate and
and environment
environment
• Temperature
• Wind
• Rainfall
• Air quality
• Fruit position on tree
Beware of
discoloured
stems
Freeze Damage
Damage
Freeze
=
Cold
Stress
= Cold Stress
Can see
increased
decay and low
temperature
damage after
storage
Effects could
last for several
weeks/months
Mary Lu Arpaia (September 2004)
9
40
Unsound
Rainfall
%Unsound or Ra infal l (mm)
35
30
25
20
15
10
5
0
1/
/1
10
0/
/1
31
01
20
01
20
01
20
0/
/1
21
01
20
0/
/1
11
01
20
0/
/1
01
01
20
9/
/0
21
01
20
9/
/0
11
01
20
9/
/0
01
Date
More
More body
body rots
rots develop
develop when
when fruit
fruit are
are harvested
harvested
during
the
rainy
period
than
dry
summer
during the rainy period than dry summer months
months
Infected fruit (%)
40 Body Rots
Stem end rots
30
Winter
Summer
20
10
0
1
2
3
1
2
3
Avocado grove location
Mary Lu Arpaia (September 2004)
10
During
During rainy
rainy periods
periods (like
(like January),
January), Colletotrichum
Colletotrichum is
is
most
common.
During
dry
periods,
Colletotrichum
remains
most common. During dry periods, Colletotrichum remains
common
common but
but Dothiorella
Dothiorella and
and other
other fungi
fungi are
are found
found
Things
Things to
to ponder
ponder
• Should freeze damaged fruit go
into the market stream?
• Should you be tempted to pick up
fruit from the ground?
• Should you pick after rain?
Mary Lu Arpaia (September 2004)
11
Rootstock and
and Variety
Variety Interactions
Interactions
Rootstock
Effect of avocado cultivar and clonal rootstock
on fruit quality following 28 days at 5.5C
100
% freedom from chilling injury
G755C
G6
80
Duke 7
60
40
20
0
Fuerte
Hass
Kohne and Kohne, 1992 (unpublished)
a
b
75
Rootstock and
and
Rootstock
Variety
Variety
Interactions
Interactions
SV
CV
CD
b
a
ns
b
b
50
b
a
Results from Australia
20 yr-old trees
a
25
0
1999
2000
1999
Diffuse
discolouration
Rootstocks affect
‘Hass’ avocado fruit
rots and
physiological
disorders
Marques, Hofman 2002
Mary Lu Arpaia (September 2004)
4 wks @ 5C
2000
Vascular
browning
Flesh volume (%)
Fruit acceptability (%)
100
40
b
SV
Seedling Velvick
CV
Clonal Velvick
Duke 7
D7
30
a
c
20
a
b
10
a
Non-stored
Stored
12
Rootstock and
and
Rootstock
Variety
Variety
Interactions
Interactions
Fruit skin
b
0.40
ab
Ca (g kg-1 DW)
ns
0.35
a
0.30
Fruit flesh
0.30
c
b
a
0.25
0.20
Seedling Velvick
Clonal Velvick
Clonal Duke 7
b
a
a
2000
1999
Year
Rootstock
Rootstock
influences
influences
Calcium levels
levels in
in
Calcium
the
fruit
the fruit
Effect of long-term irrigation regimes on the browning
potential of 'Fuerte' avocado after 30 days storage
1.4
PPO activity
1.2
1.0
0.8
0.6
0.4
0.2
0.0
35 kPa
55 kPa
80 kPa
Irrigation Regime
J.P. Bower, 1988
Irrigation effects
effects on
on fruit
fruit quality
quality
Irrigation
Increasedbrowning
browningpotential
potentialfollowing
following
Increased
storage
=
mesocarp
discoloration
storage = mesocarp discoloration
Mary Lu Arpaia (September 2004)
13
Effects of tree vigor on fruit quality
Individual tree yield records were maintained
Based on overall tree yield and storage
quality the following observations were
made:
In vigorous, low yielding trees all forms of
chilling injury were observed in higher
amounts following 28 days at 5.5C
Low yielding trees had lower pulp calcium,
zinc and manganese
D. Smith, 1992 (unpublished RSA)
Anthracnose (1-5)
Tree yield and fruit rots
(Australia)
Higher yield for
same size tree
may also reduce
postharvest
decay
r = 0.81**
4
3
2
40
80
120
160
200
240
Associated with
smaller fruit
and higher fruit
Calcium
-1
Fruit yield tree (kg)
Hofman, Vuthapanich, Whiley, Klieber, Simmons 2001
Mary Lu Arpaia (September 2004)
14
Avocado Seasonal Calcium Concentration
10
8
6
,
+
"
,
+
"
!
4
,
+
"
!
2
0
Tree
Tree vigor
vigor influences
influences
calcium
calcium levels
levels in
in the
the fruit
fruit
Fruit Ca (mg/kg DW)(X1000)
0
2
!
4
6
,
+
"
!
8
! Vigorous 'Fuerte'
" Non-Vig 'Fuerte'
+ Vigorous 'Hass'
, Non-Vig 'Hass'
Calcium
Calcium affects
affects the
the rate
rate
of
ripening
of ripening
,
+
"
!
,
+
"
!
,
+
"
!
,
"
+
!
,
"
+
!
,
"
+
!
,
"
+
!
,
"
+
!
,
"
+
!
10
12
14
16
18
20
22
24
26
Weeks after Fruit Set
Regression of Days to Fruit Ripening
and Calcium Concentration
G.W. Witney et al., 1990
y = 0.0056x + 4.856, r = 0.92**
16
Days to Ripen
!
14
12
10
8
6
!
0
500
1000
1500
2000
2500
Calcium (mg/kg DM)
Witney et al., 1990
Canopy Management/Pruning
May have
have an
an effect
effect on
on fruit
fruit quality
quality
May
Aim at
at fruit
fruit requirements
requirements not
not wood
wood
Aim
Mary Lu Arpaia (September 2004)
15
% of flesh affected
a
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
2001
2002
ab
b
Unpruned
Pruned after
harvest
Pruned again in
summer
Diffuse discoloration
Increased
Increased vegetative
vegetative
vigor
vigor from
from pruning
pruning can
can
result
in
increased
result in increased
decay
decay and
and physiological
physiological
disorders
disorders
% of flesh affected
4
a
3
a
ab
2
1
b
0
Unpruned
P runed aft er
harvest
P runed again
in summer
Leonardi, Whiley, Hofman
The relationship between subsoil (Ca+Mg)/K ratio
and the incidence of grey pulp in avocado
50
The role
role of
of
The
plant nutrition
nutrition
plant
% Grey Pulp
40
30
1990
r=-0.49
20
1989
r=-0.68
10
0
P runed in
summer +
Sunny
1.4
2.4
3.4
4.4
5.4
6.4
7.4
Subsoil (Ca+Mg)/K mg per kg
The influence of fruit calcium and zinc levels
on the incidence of pulp spot
DuPlessis and Koen, 1992
70
ppm
No Pulp Spot
60
Pulp Spot
50
40
30
20
10
0
Calcium (*)
Zinc (**)
Vorster and Bezuidenhout, 1988
Mary Lu Arpaia (September 2004)
16
HIGH
HIGH NITROGEN
NITROGEN
• EXCESSIVE VIGOUR
• LACK OF CALCIUM, BORON AND
CARBOHYDRATES TO FRUIT
• MAY RELATE TO CARBOHYDRATE
TRANSPORT
• ENZYME CO-FACTORS
• CELL FUNCTION
The influence of nitrogen nutrition on moderate/severe
chilling injury after 6 weeks at 5C.
80
60
% Moderate/Severe
"
"
"
"
"
40
"
"
"
"
"
20
0
1.77
"
"
"
2.08
2.28
2.46
2.65
2.86
3
Leaf Nitrogen (%)
The influence of nitrogen nutrition on the time
to eating ripeness.
Days to <1.5 lbf
The role
role of
of Nitrogen
Nitrogen
The
on ‘Hass’
‘Hass’ fruit
fruit quality
quality
on
8 %
%
%
%
6
&
4
2 '
0
1.77
%
%
%
%
%
%
0 wks
%
%
%
%
&
&
'
'
&
&
'
&
'
2.08
&
'
'
2.28
&
'
&
'
2.46
&
'
&
'
2.65
&
'
3 wks
&
6 wks
'
2.86
&
'
3
Leaf Nitrogen (%)
Mary Lu Arpaia (September 2004)
17
Diffuse discoloration (1-5)
r = 0 .8 3 * *
2
1
200
300
400
Calcium
Calcium fruit
fruit levels
levels
influences
influences susceptibility
susceptibility
to
to physiological
physiological problems
problems
and
and decay
decay
500
-1
C a lc iu m c o n c e n tra tio n (m g k g )
Anthracnose severity (1-5)
3
4
r = 0.88**
3
2
1
200
300
400
500
-1
Calcium concentration (mg kg )
Hofman, Vuthapanich, Whiley, Klieber, Simmons 2001
Flesh
Flesh minerals
minerals and
and diffuse
diffuse
discolouration
discolouration
Year
1994
1995
Holding
conditions
7°C, 3 wks
7°C, 5 wks
2°C, 5 wks
r value
Ca
Mg
-0.07
-0.13
0.30
0.31
-0.83 ** -0.75 **
K
0.55 *
0.06
0.51 *
Hofman, Vuthapanich, Whiley, Klieber, Simmons 2001
Mary Lu Arpaia (September 2004)
18
INTERNAL DISORDERS
• TRADITIONALLY CALCIUM
IMPLICATED
SUGGEST THAT
• MULTI-FACTOR PROBLEM
• CALCIUM NOT ALWAYS MAIN
FACTOR TO TREAT
SOLUTIONS
SOLUTIONS
• ENHANCE FRUIT SINK STRENGTH
FOR:
– CRITICAL ELEMENTS (VARIES WITH
SITE)
– CARBOHYDRATES
– CRITICAL STAGES IN FRUIT
DEVELOPMENT
Mary Lu Arpaia (September 2004)
19
PRE-HARVEST GROWING CONDITIONS
INTERACTION BETWEEN
* pre-harvest orchard temperatures
mainly external defects
* vegetative growth
external and internal defects
MASKING EFFECT
*
water stressed trees
Harvesting Operations
Operations
Harvesting
•
•
•
•
Minimum Maturity Standards
Harvesting Methods
Delay between field and packer
Harvesting conditions
Mary Lu Arpaia (September 2004)
20
Quality
Quality vs.
vs. Maturity
Maturity
Immature
6 Poor quality when ripe
6 More shriveling and physical damage
Mature
6 Good quality when ripe
6 Longest postharvest life
Overmature
6 Poor flavor
6 More Physiological disorders, decay
Immature Fruit
Quality Problems
Mary Lu Arpaia (September 2004)
21
Physiological disorders accentuated
with low maturity fruit
External Chilling Injury
Flesh Discoloration
Fruit quality to consumers is
limited by harvest maturity:
– Immature – watery, shriveling, inconsistent ripening,
physiological disorders, susceptible to decay
– Overmature – can be dry, rancid, seed germinating
and more susceptible to decay
Mary Lu Arpaia (September 2004)
22
Checkerboarding = Ripening Variability
Difficult to predict time of
ripeness
Great variation in the days to
ripe within a package even
with ethylene treatment
RESULT:
Lack of ripe uniformity
means more loss at point of
purchase
Poor RIPE Skin Colouration
Mary Lu Arpaia (September 2004)
23
Stringiness
TASTE
TASTE
California 2002-03 results
with Ventura Co. Hass fruit
2002 - 2003 Hass Maturity Project (Preliminary Results)
ALL DATA
Hedonic score vs. Dry weight
9.0
8.5
8.0
7.5
Like moderately
Average Hedonic Score
7.0
6.5
Like slightly
6.0
Clearly at lower
DW values,
acceptability of
fruit is marginal
5.5
Neither like or dislike
5.0
4.5
Dislike slightly
4.0
3.5
Dislike moderately
3.0
2.5
y = 0.1874x + 1.6404
2
R = 0.6052
2.0
1.5
Data suggest
that for a score
of 6 the CA dry
matter will be
approximately
23%
1.0
12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38
Percent Dry Weight
Mary Lu Arpaia (September 2004)
24
Discrete patches
(chilling damage)
Skin spotting
(Nodule damage)
Physical
Physical damage
damage and
and chilling
chilling
25
Discrete patches (% area)
Skin spotting (% nodules)
% damage
20
15
10
5
g
in
ac
k
Af
te
rp
rb
ru
sh
in
g
he
d
At
s
Af
te
ld
fie
In
H
an
d
ha
r
ve
st
ed
0
Mary Lu Arpaia (September 2004)
25
Physical
Physical damage
damage and
and chilling
chilling
The
The importance
importance of
of temperature
temperature
management
management when
when harvesting
harvesting
Mary Lu Arpaia (September 2004)
26
Protecting the fruit after harvest from high
temperature has implications in the market place
Temperature (F)
105
95
During the course of the day, fruit
in the TOP 12” of the bin with no
protection can reach
temperatures in EXCESS of 100
F whereas covered bins or those
held in the shade can maintain
temperatures close to ambient
85
75
TOP
65
55
1100
1130
1200
1230
1300
1330
1400
1430
1500
1530
Time
Air
Uncovered
Space
Temperature (F)
105
BOTTOM
95
Fruit at the BOTTOM of the bin
stay cool during the day
85
75
65
55
1100
1130
1200
1230
1300
1330
1400
1430
1500
1530
Time
Air
Uncovered
Space
Source: Arpaia, M. L., 1994; ‘Hass’ fruit
harvested from Riverside county.
What is the outcome of high temperatures in
the field after harvest?
% Decay
40
% Moderate/Severe Discoloration
40
30
30
20
20
10
10
0
0
Uncovered
Space
Blanket
Uncovered
BOTTOM
TOP
Space
Blanket
Uncovered
Space
Blanket
BOTTOM
Uncovered
Space
Blanket
TOP
Fruit from the BOTTOM of the bin (lower temperatures) had lower decay and less
chilling injury after storage at 41F and ripening.
However, fruit from the TOP of the bin, which were warmer, had higher levels of
both decay and chilling injury. This is especially true for the fruit which came from
the uncovered bins.
Source: Arpaia, M. L., 1994; storage was for 6 weeks at 41F.
Mary Lu Arpaia (September 2004)
27
Considerations
Considerations in
in the
the grove
grove
• Keep fruit in a cool place, out of the sun
• Work with packinghouse to minimize delays
from time of harvest to cooling
• Avoid picking when temperatures are high
especially with late season fruit
• Avoid picking during or shortly after a rain
event – more decay
• Worker Safety; HAACP considerations for
the future
Limitations to
to avocado
avocado
Limitations
postharvest handling
handling
postharvest
9 Fruit maturity and quality at time of
ripeness
– Immature – watery; inconsistent ripening
– Overmature – can be dry; seed germination and
more susceptible to decay
9 Time after harvest and how fruit are
managed
– Increased risk of physiological disorders
• Stage of ripeness
– Ripe for tonight
– More difficult to handle “ripe” fruit
Mary Lu Arpaia (September 2004)
28