Proceedings VI World Avocado Congress (Actas VI Congreso Mundial del Aguacate) 2007.
Viña Del Mar, Chile. 12 – 16 Nov. 2007. ISBN No 978-956-17-0413-8.
CORRELATION OF OIL CONTENT, DRY MATTER AND PULP MOISTURE
AS HARVEST INDICATORS IN HASS AVOCADO FRUITS (Persea
americana Mill) GROWN UNDER TWO CONDITIONS OF ORCHARDS IN
CHINCHA-PERÚ.
G. Parodi1, M. Sanchez 2 and W. Daga1
1
Instituto Nacional de Investigación y Extensión Agraria – INIEA. PNI-Frutales. Av. La Molina
1981. La Molina-Lima. Perú. Email: gparodi@inia.gob.pe, gparodi@lamolina.edu.pe,
wdaga@inia.gob.pe
2
Facultad de Agronomía. Universidad Nacional Agraria La Molina. Departamento de
Horticultura. Av. La Molina s/n Lima. Perú. Email: dhorticultura@lamolina.edu.pe
This work aimed at the determination of the correlation among oil content, dry
matter and pulp moisture in avocado fruits (Persea americana Mill) var. Hass)
grown in two locations: Alto Larán (La Calera farm) and El Carmen
(Copacabana farm), both in Chincha-Perú. Harvest started 208 days after main
flowering stage and lasted seven weeks. Results showed a positive correlation
between oil content and dry matter content of pulp in fruits from in Alto Laran (r
= 0.9583), which is shown by the regression equation y = 0.9908x – 10.43. In El
Carmen the correlation was also positive (r = 0.9544) and its equation was y =
0.9754x – 10.32. The oil and pulp moisture content had an inverse correlation in
Alto Laran (r = -0.9583) with a regression equation as y = -0.9908x + 88.65. In
El Carmen the negative correlation (r = -0.9544) was explained through the
regression equation y = -0.9754x + 87.22. The postharvest respiratory curve of
the avocado fruits showed a typically climacteric response, obtaining the
climacteric crisis 16 days after fruit harvested in Alto Laran and within 18 days
in those harvested in El Carmen.
Key words: maturity indices, harvest, postharvest, correlation
CORRELACIÓN DEL CONTENIDO DE ACEITE, MATERIA SECA Y
HUMEDAD DE PULPA COMO INDICADORES DE COSECHA EN FRUTOS
DE PALTO (Persea americana Mill) VAR. HASS CULTIVADA BAJO
CONDICIONES DE DOS LOCALIDADES EN CHINCHA-PERÚ.
G. Parodi1, M. Sanchez 2 y W. Daga1
1
Instituto Nacional de Investigación y Extensión Agraria – INIEA. PNI-Frutales. Av. La Molina
1981.
La
Molina-Lima.
Perú.
Correo
electrónico
gparodi@inia.gob.pe,
gparodi@lamolina.edu.pe, wdaga@inia.gob.pe
2
Facultad de Agronomía. Universidad Nacional Agraria La Molina. Departamento de
Horticultura. Av. La Molina s/n Lima. Perú. Correo electrónico: dhorticultura@lamolina.edu.pe
Se realizó un ensayo con el objetivo de determinar el grado de correlación
entre el contenido de aceite, materia seca y humedad de pulpa en frutos de
palta (Persea americana Mill) var. Hass cultivada en dos localidades, Alto Larán
(predio La Calera) y El Carmen (predio Copacabana) ubicados en ChinchaPerú. La cosecha de los frutos se inicio a los 208 días después de cuajada la
floración principal. La recolección de frutos se realizó durante siete semanas
consecutivas. Los resultados muestran una correlación positiva entre el
contenido de aceite y el de materia seca de la pulpa en los frutos provenientes
de la localidad Alto Larán (r = 0.9583), la cual se interpreta a través de la
ecuación de regresión: y = 0.9908x – 10.43; mientras que para los frutos
provenientes de la localidad El Carmen la correlación positiva (r = 0.9544) se
interpreta mediante la ecuación: y = 0.9754x – 10.32. El contenido de aceite y
humedad de pulpa mostraron una correlación inversa en la localidad Alto Larán
(r = -0.9583), y una ecuación de regresión de: y = -0.9908x + 88.65, mientras
que en la localidad de El Carmen la correlación inversa (r = -0.9544) se
interpretó a través de la ecuación: y = -0.9754x + 87.22. El ritmo respiratorio
poscosecha de los frutos mostró un comportamiento típicamente climatérico,
obteniéndose a los 16 días el instante de crisis climatérica en aquellos frutos
provenientes de la localidad Alto Larán, y a los 18 días en los recolectados en
la localidad de El Carmen.
Palabras claves: índices de madurez, recolección, poscosecha, correlación.
1. Introduction
The quality of the fruits is a combination of attributes which bring value to them
as food. Therefore, it is very important to sustain these attributes by conducting
a timely harvest at the optimum moment (Kader, 1992; Pantastico, 1985). In the
case of avocado, the time of harvest is very important to obtain a satisfactory
storage (Cajuste, 1992; Parodi and Lerner, 1995). Generally, it is difficult to
determine visually when an avocado fruit is ready to be picked off, due to the
fact that it does not show notable changes in its external appearance (Lee,
1981; Lewis, 1978; Pantastico, 1975). In reference to avocado harvest
indicators, perhaps the most important of them is the determination of oil (INIA,
1997), due to the direct relation among the maturity grade of fruit and the oil
accumulation and dry matter (Lee et al., 1983; Lewis, 1978). Nowadays, the oil
content as well as the dry matter content are used in almost all the regions of
the world that produce avocado, in order to determine a minimum maturity for
the fruit (Parodi, 1996). These indicators are also applied in the Peruvian case,
although there is not accurate information by valleys or zones regarding the
minimum level of oil that fruits require to start the harvest (Parodi, 1998).
Usually, the Peruvian central coast valleys start the Hass avocado harvest with
minimum oil content of 8 -9 % and dry matter content of 20-21% (Franciosi,
2003). Nevertheless, since there is a lack of accurate data, it was suggested
that values could be higher than the abovementioned (Parodi 1996). The
objective of this work was to research about Hass avocado fruits cultivated in
two locations of Chincha in order to determine not only the correlation degree of
oil content with dry matter and with pulp moisture for Hass, but also the
variation in these parameters during the period of harvest.
2. Materials and Methods
The test considers two locations: Alto Larán (Fundo La Calera at 201 m.a.s)
and El Carmen (Fundo Copacabana at 102 m.a.s), both situated in Chincha-Ica.
Just after set fruit, a total of 308 fruits resulting from the main flowering of
August-September were marked in each location. The harvest started 208 days
after set fruit (asf) is over, and 44 fruits were picked off once a week during 7
weeks in each location. These fruits were placed in a preconditioned
environment with a temperature which fluctuated between 20 and 24ºC, in order
to obtain its postharvest natural ripening. There were obtained 4 repetitions of 2
fruits from the 44 harvested fruits, which were used to estimate the harvest
indicators. The remaining 36 fruits were distributed in 9 samples composed by 2
repetitions of 2 fruits, which were used to determine the respiratory rhythm. The
model of simple linear correlation, which was applied as statistical test for the
experimental work, determined the relationships between oil content and dry
matter and between oil content and pulp moisture and obtained the association
intensity using the correlation coefficient. During the test period, the statistic
analysis of changes in harvest indicators was developed by one-way ANOVA
with a CDR arrangement that considered 7 treatments, where each week was
assumed as a treatment composed by 4 repetitions. Likewise, a Tukey’s Mean
Separation Test was performed with a significance level of 1%. The evaluations
performed were:
Respiration intensity: Expressed as ml CO2 kg-hr-1 liberated by the avocado
fruits inside a hermetically -sealed glass container. A MOCON gas analyzer
was applied during the test.
Dry matter and pulp moisture: Obtained by weight difference of 50 grams of fruit
pulp placed in a MEMMRET oven at 70ºC during 48 hours.
Oil content: Obtained by the method of extraction that employs a Soxhletdistiller. The official USDA procedure for determination the oil content of
vegetable organs was followed employing petroleum ether as solvent (Lee,
1981).
3. Results and Discussion
Correlation between oil concentration versus dry matter and pulp moisturet:
The obtained results in terms of oil content expressed as a function of dry
matter content (Fig.1) showed a higher positive correlation; it means that, in the
case of avocado fruits, the dry matter content increases as the oil content
increases. Alto Larán showed a correlation coefficient (r) of 0.9583, while El
Carmen obtained r = 0.9544. The high degree of correlation between these two
components has been mentioned before by other researchers (Lee et al., 1983;
Ranney, 1991). On the other hand, it was obtained a high inverse correlation
between oil and moisture contents of avocado fruits (Fig. 2). It means that there
is an increase of oil content with a reduction of the moisture content. In this
case, Alto Larán showed a correlation coefficient (r) of -0.9583, while El Carmen
obtained r = - 0.9544. The relation degrees obtained between oil and dry matter
contents or between oil content and percentage of pulp moisture are interesting
due to the fact that oil percentage in avocado fruits results feasible to estimate
by these two components. In this case, there is the possibility to estimate oil
content using as references the dry matter or the moisture content and applying
the equations resulted of a simple linear regression, which are practical and
easy to follow (Lee, 1981).
15.00
17.00
16.00
Contenido de aceite (%)
Oil content (%)
y = 0.9754x - 10.318
R2 = 0.9139
y = 0.9908x - 10.43
R 2 = 0.9183
14.00
El Ca rm e n
15.00
13.00
Alto Larán
14.00
12.00
13.00
11.00
12.00
11.00
21.00
22.00
23.00 24.00 25.00
Materia seca (% )
Dry matter (%)
26.00
27.00
10.00
20.00
22.00
24.00
Materia s eca (% )
Dry m atter
Figure 1: Oil content in avocado fruits (Persea americana Mill) var. Hass in
function of the dry matter content.
1 5 .0 0
17.00
1 4 .0 0
y = -0.9908x + 88.65
R 2 = 0.9183
y = -0 .9 7 5 4 x + 8 7 .2 2 2
R 2 = 0 .9 1 3 9
15.00
Oil content (%)
Contenido de aceite (%)
16.00
1 3 .0 0
A lto L a rá n
El C a rm e n
14.00
1 2 .0 0
13.00
1 1 .0 0
12.00
11.00
73.0 0 74.00 7 5.00 76.00 77 .00 78.00 79.00
C o n te n id o d e H u m e d a d (% )
H u m id ity c o n te n t (% )
1 0 .0 0
7 4 .0 0 7 5 .0 0 7 6 .0 0 7 7 .0 0 7 8 .0 0 7 9 .0 0 8 0 .0 0
Co n te n id o d e Hu me d a d ( % )
Hu mid ity c o n te n t
Figure 2: Oil content in avocado fruits (Persea americana Mill) var. Hass in
function of the pulp moisture.
26.00
Respiration intensity: The behavior of typically climacteric respiration
presents a particular evolution of the fruits depending on their location of origin
(Fig.3). The fruits produced in Alto Larán show their moment of climacteric crisis
16 days after harvest, except in the third week when the climacteric crisis
110,0
Respiracion en ml CO2/kg-hr
Respiration ml CO2/kg-hr
100,0
Alto Larán
90,0
80,0
70,0
60,0
50,0
40,0
30,0
20,0
0
2
4
6
8
10
12
14
16
18
Días después de cosecha
Days after harvest
110,0
100,0
El Carmen
Respiracion en ml CO2/kg-hr
Respiratory ml CO2/kg-hr
90,0
80,0
70,0
60,0
50,0
40,0
30,0
20,0
0
2
4
6
8
10
Días después de cosecha
Days after harvest
Cosecha de 208 días/Harvest of 208 days
Cosecha de 222 días/Harvest of 222 days
12
14
16
18
Cosecha de 215 días/Harvest of 215 days
Cosecha de 229 días/Harvest of 229 days
Cosecha de 236 días/Harvest of 236 days
Figure 3: Respiratory curve of avocado fruits (Persea americana Mill) var. Hass
harvesting by seven weeks in Alto Larán and El Carmen.
occurred on day 18, with maximum values between 93.4 and 105.0 ml CO2 kgh-1. Nevertheless, the fruits obtained from El Carmen reached the moment of
climacteric crisis on day 18, except in the cases of the third and fourth weeks
when the climacteric crisis occurred on day 16, with maximum values between
81.4 and 107.1 ml CO2 kg-h-1. Generally, the registered levels of respiratory
intensity fall within the ranges considered for Hass avocado fruits (Briceño
1994; Eaks 1978). However, it is important to remark that fruits produced in Alto
Larán tend to soften faster than those obtained at El Carmen, due to the set of
external conditions or management conditions under which plantations produce
in each location. This aspect determines the particular behavior during the
postharvest maturity process of avocado fruits (Kader, 1992; Pantastico, 1975).
Changes in the oil content, dry matter and pulp moisture:
The oil and dry matter contents and the pulp moisture for each evaluated location
showed statistical differences regarding the harvest moments. The obtained
results of oil contents showed that it increased while the harvest of fruits was
performed each time later (Fig.4). Under Alto Larán conditions the highest
results of oil content were obtained at 243 asf (14.63%) and 250 asf (15.85%),
while The Carmen showed the highest values of oil content at 243 asf (12.58%)
and 250 asf (13.44%). The variation in oil content was 3.82% from the first to the
last moment of harvest at Alto Larán, while the same indicator was 2.38% at El
Carmen. It means that fruits produced in Alto Larán showed values of oil content
somewhat higher than those obtained at El Carmen. Likewise, the dry matter
content also increased as the harvests were performed each time later (Fig 5).
The picked fruits from Alto Larán reported increases since the harvest that was
performed at 222 asf; later these values stood until a level of 243 asf and at the
end they reached a level of 250 asf. El Carmen response was similar to the one
obtained at Alto Larán: an increase in dry matter of fruits was observed since the
level of 222 asf, then it stood until a level of 243 asf and it showed again a light
increase at 250 asf. However, El Carmen always showed values of dry matter
content lower than those obtained from Alto Larán at any of the harvest
moments. In terms of moisture content of the pulp, it showed a downward trend
during the harvest period. The fruits obtained from Alto Larán showed at 222 asf
a first remarkable change in their moisture content, which didn’t report great
differences until a level of 243 asf and then decrease again at 250 asf. El
Carmen showed a similar trend but with lower values of moisture content in fruits.
The trends observed in terms of oil and dry matter and moisture contents of the
pulp are related to those reported by other authors (Cajuste, 1992; Lee et al.,
1983; Lewis, 1978; Ranney, 1991). Likewise, the increases of oil and dry matter
contents as well as the steady decrease of moisture content in Hass avocado
fruits, while the harvests for both locations are performed each time later, clearly
show the fruit capability of Hass avocado tree to accumulate oils while it remains
on tree (Parodi 1996).
17.00
15.00
15,85
d
Contenido de aceite (%)
Oil content (%)
16.00
Alto Larán
15.00
Tukey P<
0.01
14.00
El Carmen
14,63
cd
14.00
12,03
a
11,87 11,92
bc
bc
12.00
13,19
ab
13.00
12,58
cd
13.00
14,10
bc
13,98
bc
13,44
d
11.00
12,24
a
12.00
11,25 11,33
ab
ab
10,61
a
10.00
11.00
9.00
10.00
208
215
222
229
236
243
8.00
250
208 215 222 229 236 243 250
Días despues de cuajado
Days after fruit set
Días después de cuajado
Days after fruit set
Figure 4: Oil content changes in avocado fruits(Persea americana Mill) var.
Hass to differents harvest moments.
27.00
26,10
c
Alto Larán
Contenido de materia seca (%)
Dry matter content (%)
26.00
Tukey P <0.01
24,48
b
25.00
24,63
b
24,98
b
25,28
bc
25.00
24.00
22,33
a
23,65
cd
24.00
23.00
23.00
24,25
d
El Car m e n
22,83
a
22.00
22,25
ab
22,28
b
215
2 22
22,45
b
22,90
bc
21,38
a
2 1.00
22.00
20.00
21.00
19.00
20.00
208
215
222
229
236
Días despues de cuajado
Days after fruit set
243
250
20 8
2 29
236
243
Días des pues de c uajado
Day s af ter f ruit s et
250
Figure 5: Dry Matter changes in avocado fruits (Persea americana Mill) var.
Hass to differents harvest moments.
Contenido de humedad (%)
Humidity content (%)
79.00
78.00
80.00
77,68
77,18
a
a
Tukey P<0.01
79.00
77,75
ab
Alto Larán
77.00
75,53
b
76.00
78,63
a
75,38
b
78.00
75,03 74,98
b
bc
75.00
77,73
b
77,55
b
El Carmen
77,10
bc
77.00
73,90
c
76,35
cd
76.00
75,75
d
74.00
75.00
73.00
74.00
72.00
73.00
71.00
208
215
222
229
236
Días despues de cuajado
Days after fruit set
243
250
208
215
222
229
236
243
250
Días despues de cuajado
Days after fruit set
Figure 6: Pulp moisture changes in avocado fruits (Persea americana Mill) var.
Hass to differents harvest moments.
4.Conclusions
•
•
•
•
•
The oil and dry matter contents showed a positive correlation at Alto
Larán (r =0.9583) and at El Carmen (r =0.9544).
The oil content and the fruit moisture had a high inverse correlation at
Alto Larán (r = - 0.9583) and at El Carmen (r = - 0.9544).
The fruits produced in Alto Larán had a climacteric crisis 16 days after
harvest, while at El Carmen the climacteric crisis was on day 18.
The percentages of oil and dry matter showed an upward trend, while the
harvests were performed each time later.
The moisture content showed a progressive downward trend, while the
harvests were done each time later.
5. References
• Briceño, L. 1994. Utilización de envases flexibles para el
almacenamiento refrigerado de la Palta (Persea americana Mill) Var.
Hass en atmósfera modificada autogenerada. Tesis Mag. Sc.
Tecnología de los Alimentos. Universidad Nacional Agraria La
Molina. Escuela de Postgrado. Lima-Perú. 160p.
• Cajuste, J. 1992. Efecto del grado de madurez en la frigoconservación
de aguacate (Persea americana Mill) cv. Hass. Tesis Maestría en
•
•
•
•
•
•
•
•
•
•
•
•
Ciencias. Colegio de Postgraduados. Programa de fruticultura.
Montecillo – México. 183p.
Eaks, I. 1978. Ripening, Respiration, and Ethylene Production of “Hass
Avocado Fruits at 20° to 40°C. J. Amer. Soc. Hort. Sci. 103: 576.
Franciosi, R. 2003. El Palto. Producción, cosecha y post-cosecha.
Ediciones Cimagraf. Lima – Perú. 225p.
INIA, CONAFRUT.
1997.
El cultivo del Palto. Aspectos de la
producción, manejo post-cosecha y comercialización. Boletín
Técnico Nº 9. 47p.
Kader A, 1992. Indices de Madurez, Factores de Calidad, Normalización
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Postcosecha de Productos Hortícolas . Yahia, E y Higuera, I.
Editores. Edit Limusa- Mexico 303 pp.
Lee, S. 1981. A review and background of the avocado maturity
standard. California Avocado Soc. Yearbook. 65. p 101 – 109.
Lee , S.K. , R.E Young , P.M. Schiffman, and C.W. Coogins, Jr. 1983.
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weigth. J. Amer. Soc. Hort. Sci. 108:390-394
Lewis, C. E. 1978. The maturity of avocados: a general review. J. Sci.
Food Agric. 29. p 857-866.
Pantastico, B. 1975. Postharvest Physiology. Harding and Utilization of
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Parodi, G. 1996. Manejo de Cosecha y Postcosecha del Palto. Curso
Teórico Práctico sobre Fisiología, Manejo de Cosecha y Postcosecha
en Frutas y Hortalizas. Facultad de Agronomía.Dpto HorticulturaUNALM. s/n
Parodi, G. 1998. Aspectos Sobre Manejo en Cosecha y Post Cosecha
del Palto. I Seminario Taller Internacional. Producción, Manejo Post
Cosecha y Comercialización de Frutas y Hortalizas. UNALM - Lima.
Parodi, G. y Lerner, M. 1995. Ensayo sobre Almacenamiento en Frío de
Palto “Hass”. Proc. Interamer. Soc. Trop. Hort. 39: 86-93
Ranney, C. 1991 Relations between physiological maturity and percent
dry matter of avocados. California Avocado Society Yearbook. 75: 7185.