close

Вход

Забыли?

вход по аккаунту

?

691

код для вставкиСкачать
J Sci Food Agric 1996,71,345-350
Effect of Altitude on Fruit and Oil Quality
Characteristics of ‘Mastoides’ Olives
Yiasser Mohamed Mousa, Dimitrios Gerasopoulos*
Mediterranean Agronomic Institute of Chania, Horticulture and Technology Dept Macedonia Rd,
PO Box 85, Chania 73100, Greece
Ioannis Metzidakis
Subtropical Plants and Olive Trees Institute, Agrokepion Chania 73100, Greece
and Apostolos Kiritsakis
Technological Institute of Thessaloniki, Sindos 57400, Greece
(Received 24 April 1995; revised version received 25 September 1995; accepted 2 February 1996)
Abstract: Olive fruit of cv ‘Mastoides’ grown on two locations at altitudes of 100
and 800 m were harvested at three dates and used for determination of average
weight, fruit oil and moisture contents and the following oil quality characteristics: titratable acidity, peroxide value, K z s z .270 coefficients, total phenol,
tocopherol and chlorophyll content as well as fatty acid and phenol composition.
Towards maturation, fruit moisture content decreased but oil content increased.
Titratable acidity of oil of both altitudes was low, with higher the oil obtained
from fruits from 100 m. Oil peroxide value was higher in the oil of fruits from
800 m at all harvest times and it showed an increase towards maturation in both
locations. Total phenol content was higher in oil from 100 m elevation and
showed a gradual decrease towards maturation at both altitudes. The ratio
unsaturated saturated fatty acids was higher in oil of fruits from 800 m at the
first two harvest dates but did not differ significantly at the third harvest. Only
a-tocopherol was found in the oil from both elevations. Some phenolic compounds were detected in the first harvest but disappeared with fruit maturation,
while other compounds not detected in the first harvest appeared later. Elevation
influenced not only the phenol content but also its composition.
Key words: olive tree, cv ‘Mastoides’, olive oil quality, phenolic compounds, fatty
acids.
INTRODUCTION
1990; Kiritsakis 1991). The altitude at which the olive
trees are grown also affect the quality characteristics of
olive oil and mainly its composition. Olive oil from high
elevation has higher oxidative stability compared with
the oil from lower elevations (Osman et a1 1994). Within
the same growing area, as the temperature decreases
(higher elevation) the percentage of unsaturated fatty
acids increases (Kiritsakis and Markakis 1987).
The objective of this study was to investigate the
effect of altitude (100 and 800 m) on several quality
characteristics of olive oil.
Olive oil is one of the oldest known vegetable oils and it
plays a fundamental role in human nutrition around the
Mediterranean basin. Recent research has shown the
importance of olive oil quality and, mainly, composition
in lowering the frequencies of several human diseases
(Fontanaua 1988). The quality of olive oil is affected by
genetic, agronomic and environmental factors (Cimato
* To whom correspondence should be addressed.
345
J Sci Food Agric 0022-5142/96/$09.00
1996 SCI. Printed in Great Britain
346
Y M Mousa et a1
TABLE 1
Quality characteristics of olive oil extracted from Mastoides olives grown at 100 and 800 m
altitude locations, harvested at three different dates”
Parameters
Average weight
(g per 100 fruit)
Moisture content
FW)
Oil content
(g k g - ’ DM)
Titratable acidity
(g kg-’ oil)
Peroxide value
(meq 0, kg-’ oil)
(g kg-
K23z
Total phenols
(mg kg-’ oil)
Tocopherol content
(mg kg-’ oil)
Chlorophyll content
(mg kg-’ oil)
Elevation
Low
High
Low
High
Low
High
Low
High
Low
High
Low
High
Low
High
Low
High
Low
High
Low
High
Harvest date
14 Dec 1993
7 Feb 1994
1 April 194
Average
153.00 f
149.00 e
441.0 d
41 1.0 b
486.0 b
541.0 d
3.2 a
3.1 a
7.40 a
8.20 ab
1.43 a
1-68 d
0.149 a
0.156 d
398.03 a
262.20 b
135.10 a
101.60 ab
8.70 a
11.20 b
143.00 d
123.00 a
424.0 c
453.0 e
564.0 e
398.5 a
4.8 b
3.8 c
8.50 b
9.60 d
1.789 b
1.939 e
0.173 b
0.214 e
389.60 a
197.20 d
109.90 a
97.80 ab
8.20 c
9.50 d
127.00 a
139.00 c
387.0 a
425.0 c
502.0 c
584.0 f
10.6 e
5.3 d
11.10 c
13.00 e
1.99 c
2.37 f
0.196 c
0.249 f
188.17 c
98.40 e
88.80 b
86.60 b
6.20 e
6.80 f
141.00
137.00
417.3
429.6
517.3
507.8
6.2
4.0
9.00
10.26
1.739
1.996
0.172
0.206
325.26
185.90
111.26
95.33
7.70
9.16
Each value is a mean of three replications. Means with the same letter within each parameter
measured (in both low and high elevations) do not differ significantly with the multiple comparison Duncan test (at P = 0.05).
EXPERIMENTAL
Six trees, of cv ‘Mastoides’ grown in locations at 100 m
(low) and 800 m (high) altitude in Chania Greece were
selected (two trees were considered as one replication)
and approximately 2 kg of olives per replication (14
Dec 1993, Feb and 1 April 1994) was harvested at
random at three harvest dates. The fruit were cleaned
from leaves and other debris, washed with tap water
and divided into two subsamples.
Fruit of the first subsample, were weighed and the
average weight per 100 fruit was recorded. The fruit
were then crushed and 50 g of the paste dried in a ventilated oven at 80°C. The dried matter was weighed, the
moisture content recorded and the total oil extracted
using a Soxhlet apparatus with benzene as solvent. The
oil content was calculated as g kg-’ dry matter.
Fruit of the second subsample (1 kg) were cleaned
and then crushed. The paste obtained was malaxed for
30 min at 32°C and then given an initial centrifugation
at 7000 x g for 20 min. The liquid phase of the paste
was then collected and the oil was recovered by a
second centrifugation at 6000 x g for 20 min. The oil
obtained was then stored in 50 ml Teflon-lined, screw-
capped test tubes at -20°C
quality characteristics.
until analysed for oil
Analysis of oil quality characteristics
Titratable acidity, peroxide value (PV), chlorophyll
content and UV absorbance at 232 ( K 2 J and 270 nm
( K 2 , 0 ) were determined according to American Oil
Chemist’s Society methods (1978). Extraction of polar
fraction was performed according to Vasquez Roncero
(1978) as modified by Tsimidou et a1 (1992) using caffeic
acid as a standard.
Phenol analysis
Identification of phenol composition was achieved by
using reversed-phase HPLC, (Tsimidou et al 1992). Phenolic compounds were separated and determined using
a Hewlett Packard 1090 series 11, HPLC system
equipped with a diode-array detector, a Lichrospher
347
Effect of altitude on olive qua1,ity
TABLE 2
Composition of phenolic compounds (% total pc) of olive oil extracted from Mastoides olives grown at altitudes of 100 and 800 m
and harvested at three different dates
~~
Compound
Retention
Time
(min)
6.05
9.33
16.76
21.00
2 1.47
25.12
27.26
29.36
33.18
34.15
36.20
36.75
37.15
37.42
37.50
37.60
37.80
38.29
38.46
39.99
41.15
4 1.40
42.38
42.81
42.96
43.60
44.10
44.23
44.94
45.50
45.90
46.42
47.30
57.50
Gallic acid
Protocatechnic acid
Tyrosol
Unknown
Vanillic acid
Syringic acid
p-coumaric acid
Ferulic acid
o-coumaric acid
Unb
Un
Un
Un
Un
Un
Un
Un
Un
Un
Un
Un
Low
High
Low
High
Low
High
-
0.13 f 0.10
0.63 +_ 0.1
0.73 f 0.03
-
-
-
-
2.08 f 0.20
1.87 +_ 0.15
0.23 +_ 0.08
3.47 f 0.19
2.69 f 1.27
3.40 f 1.24
20.70 f 4.15
0.23 f 0.12
10.32 f 0.78
13.25 f 0.98
1.10 +_ 0.43
1.96 f 0.05
8.68 f 2.12
11.22 f 2.25
4.31 f 0.89
5.35 f 1.05
3.24 f 0.65
0.79 f 0.09
1.77 f 0.28
2.26 f 0.18
2.10 f 1.4
2.23 _+ 0.16
0.97 f 0.06
6.66 & 1.68
0.80 0.14
3.96 f 1.02
0.90 _+ 0.19
-
1.58 +_ 0.35
5.80 f 0.92
-
2.13 f 0.86
-
5.54 f 1.3
12.00 +_ 1.65
0.24 f 0.16
17.83 f 0.89
13.20 f 1.42
1.87 f 0.69
0.70 f 0.02
2.20 f 0.01
5.47 f 0.31
13.43 f 1.24
2.07 f 0.23
Un
-
3.43 f 1
4.83 f 0.31
1.40 f 0.3 1
0.93 f 0.08
2.80 f 0.41
0.43 f 0.08
1.53 f 0.28
0.57 f 0-35
Un
Un
Un
Un
Un
Un
Un
Un
Un
Un
1 April 1994
7 Feb 1994
14 Dec 1993
Un
Un
Total
a
Harvest date
name
-
1.13 f 0.17
0.90 f 0
1.00 f 0.33
0.06 f 0.02
7.40 f 1.21
27.63 f 3.15
-
10.96 f 0.20
17.93 f 4.81
-
8.28 f 1.41
12.53 f 0.49
2.23 f 2.3
0.17
4.40 f 0.63
2.40 f 0.31
-
0.70 f 0.46
0.53 f 0.17
-
-
0.93 f 0.11
2.00 1.2
1.63 f 0.26
*
-
-
10.50 f 2
8.53 f 1.51
31.65 f 1.23
3.53 f 0.49
2.80 & 0.84
1.47 f 0.26
1.00
1.65 f 0.24
4.43 k 0.58
8.33 f 1.63
3.10 & 0.31
-
2.67 f 0.52
5.87 k 1.21
0.47 f 0.03
4.43 +_ 0.86
-
-
0.23 f 0.26
-
0.17 f 0.02
3.17 f 0.55
1.67 k 0.34
-
100
100
100
-
1.13 0.56
0.79 f 0.05
1.41 f 0.53
-
19.01 1.05
0.64 0.26
0.80 f 0.57
2.00 f 0.58
1.79 f 0.12
3.10 f 0.57
8.13 f 1.23
7.16 f 1.68
3.93 & 0.26
0.96 f 0.08
3.83 & 0.78
2.76 & 0.16
1.16 f 0.07
2.57 0.25
8.73 f 1.49
2.83 f 0.67
6.13 f 1.24
1.63 0.06
1.80 f 0.48
100
100
-
-
1.63 f 0.95
0.82 f 0.06
-
8.23 f 2.05
4.09 f 0.24
12.69 f 1.37
-
6.57 f 0.76
-
-
2.06 f 0.46
14.32 f 2.64
18.49 f 3.12
14.22 f 1.57
9.06 f 0.96
2.97 f 0.67
-
0.44 f 0.20
-
2.50 f 0.26
0.37 0.02
0.33 f 0.08
1.22 f 0.26
-
-
100
Each value is a mean of three replications and is followed by SD.
Unidentified compounds.
100 RP-18 column (250 x 4 mm id) and a Lichrospher
(5 pm,100 rp, 4 x 4) guard column at 37°C. The elution
solvents were acetic acid (20 ml litre-') and absolute
methanol at a flow rate of 1 rnl min-' in a gradient.
a Hewlett Packard 5890 series I1 gas chromatograph
equipped with a flame ionisation detector and a
capillary column
(HP-FFAP, 50 mm x 0-2 mm
id x 0.33 pm film thickness), at column, injector and
detector temperatures of 225, 250 and 280"C, respectively.
Fatty acid analysis
Tocopherol analysis
Fatty acids were derivatised according to the American
Oil Chemist's Society method (1978) and determined on
Tocopherol was identified and quantified according to
Tonolo and Marzo (1989) using a Hewlett Packard
348
Y M Mousa et a1
1090 series I1 HPLC equipped with a diode array detector (280 nm) on RP-18 column, with methanol/water
(96/4 v/v) for mobile phase.
Statistical analysis
The mean separation was calculated using Duncan's
test utilising procedures within the SAS system.
RESULTS AND DISCUSSION
The average fruit weight of both altitudes showed a
decrease (by YO) from the first to the last sampling
(Table 1). Fruit of cv Mastoides at maturity become
easily detached and drop to the ground. Sampling of
olives was performed directly from the tree indicating
that these fruit were of delayed maturity and therefore
of lower weight compared with the fruit that dropped
by wind action.
Fruits from the low altitude showed a gradual
decrease in the moisture content (Table 1). However,
fruits from the high altitude showed a change in the
moisture content which may be related to the weather
relative humidity, rainfall and the oil content of the
fruit. Olive oil content followed a sequential fixed
pattern, progressively increasing towards maturation in
parallel with fruit development at both altitudes (Table
1). Similar results were reported by Fernandez Diez
(1971). Donaire et al (1975), reported that there is a
change in olive moisture content as oil content progressively increases during fruit maturation.
Titratable acidity of olive oil obtained from fruit of
both elevations increased during fruit maturation (Table
1). This was probably due to increasing activity of
endogenous lipases with the development of maturity
(Kiritsakis and Markakis 1984; Kiritsakis and Tsipeli
1992). Osman et a1 (1994) reported that oil from lower
elevation contained larger amounts of free fatty acids
than that from higher elevation. Although oil acidity
increased progressively, at the end of the experiment it
was lower than the limits set by International Olive Oil
Council (1991) for the grade extra virgin.
The observed increase in K 2 3 2 and K270of oil
extracted from fruits of both altitudes with fruit maturation paralleled the decrease in total phenols and
tocopherols (Table 1). Similarly, at all harvest times, oil
from 100m had lower K coeffxients than that from
800 m (Table 1). It seems that natural antioxidants
probably delayed the formation of hydroperoxides by
scavenging the free radicals (Dugan 1961; La Notte and
Romito 1972) even when the oil is in the fruit. Although
there was a continuous increase in K coef!icients with
the harvest time (Table l), at the end of the experiment
the values were lower compared with the ones set by the
International Olive Oil Council (1991) for characterising good olive quality.
The peroxide value of olive oil extracted from fruit
grown at low elevation was lower compared with that
at high elevation (Table 1). Oil PV progressively
increased from the first to the last harvest at both attitudes by approximately 33%. Kiritsakis and Markakis
(1984) also reported that oxidation is initiated in the
fruit and increases slowly during fruit maturation. This
increase may be related to lipoxygenases which exist in
the fruit (Naudet 1965). P V correlated with phenol
content (r = 0.9) at both elevations (Osman et a1 1994).
Phenol content was 398 and 262 mg kg-' at the first
harvest and decreased considerably (by 52 and 66%)
with fruit maturity (Table 1) for the low and high elevations, respectively (Chimi et al 1988; Maestro Duran
1990, Osman et al 1994).
Several phenolic compounds were present in olive oil
samples obtained from both elevations (Table 2),
however, only the following nine were identified : gallic
acid, protocatechuic acid, tyrosol, vanillic acid, syringic
acid, p-coumaric acid, ferulic acid and o-coumaric
acid (Fig. 1). Olive oil of fruits collected from low
altitude contained initially only four compounds
(protocatechuic acid, tyrosol, vanillic acid and ocoumaric acid). At the second harvest protocatechuic
acid disappeared while at the third harvest syringic acid,
p-coumaric acid and ferulic acid appeared. Gallic acid
f
c
l
a
m
Retention time, (min)
x)
10
50
L
w
Fig 1. Chromatogram of phenolic compounds of oil extracted
from Mastoides olives grown at 100 m altitude locations.
349
EfSect of altitude on olive qualiry
Table 3 shows the changes in fatty acid composition
of olive oil from the fruit of low and high elevations
during fruit maturation. Palmitic acid decreased while
linoleic acid increased between the first and third harvests. The ratio unsaturated/saturated fatty acids for oil
from the low elevation was 5-8, 6.32 and 7-09 for the
first, second and third harvest, respectively. This ratio
was even higher for the high elevation (Table 3). The
higher ratio for the oil from the high elevation is probably related to the fact that low temperature favours the
oil unsaturation. Similar results were reported by
Osman et a1 (1994). The higher level of unsaturated
fatty acids in the oil from the higher altitude, compared
with the lower altitude may accelerate the oxidative
deterioration (Kiritsakis 1991).
was detected only in the oil from high altitude at the
first harvest indicating the influence of altitude and
maturity on the formation of the phenolic compounds.
Protocatechuic acid was found only at the first harvest
at both altitudes. These results indicate the both gallic
and protocatechuic acids are easily degraded during
maturation compared with other compounds.
Tocopherol content of oil from the low altitude was
higher (by 35%), compared with the higher one (Table
1). For both locations tocopherol content decreased
with fruit maturity from 135 to 88 mg kg-' (low
elevation) and from 101 to 86 mg kg-' (high elevation).
In oil from both altitudes only a-tocopherol was
detected which is the main tojcopherol present in olive
oil (Boatella 1975; Andrikopoulos et al 1989). The antioxidative role of tocopherols in delaying deterioration
of the oil from oxidation well known (Maestro Duran
1990).
Chlorophyll in oil from both elevations decreased
during fruit maturation (Table 1). The loss of chlorophylls paralleled the formation of other pigments,
such as anthocyanins, responsible for the purple colour
of the olives, or the products of oxidation of phenolic
compounds (oluropein), responsible for the blue colour
(Vaughn et al 1961; Fedeli 1977). In all harvest dates,
oil from the high altitude had higher chlorophyll
content compared with the low altitude, which may be
due to the fact that olives grown in the high altitude
reach maturity more slowly. This may also indicate the
chlorophyll content contributed to the photooxidative
deterioration of oil thus increasing PV (Interesse et al
1971; Carlsson el a1 1976)
CONCLUSIONS
Oil, moisture content and average fruit weight differed
significantly for the olives of the same cultivar grown at
two different altitudes. Titratable acidity for the oil of
both elevations was low and showed a progressive
increase towards fruit maturity. K coefficients of the oil
from the two elevations differed significantly. The
amount of total phenols and individual phenols were
significantly affected by elevation. The proportion of
unsaturated fatty acids was greater in the oil from the
high elevation. In conclusion, altitude appears to have a
significant effect on the quality characteristics and the
chemical composition of olive oil.
TABLE 3
Fatty acid composition of oil extracted from Mastoides olives grown at 100 and 800 m altitude locations, harvested at three
different dates"
Fatty acids
Harvest date
(% total F A )
14 Dec 1993
Palmiitc 16 : 0)
Palmitoleic acid (16 : 1)
Stearic acid (18 : 0)
Oleic acid (18 : 1)
Linoleic acid (118 : 2)
Linolenic acid (18 : 3)
Arachidic acid (20 : 0)
Saturated FAb
Unsaturated FAb
R US FA'
7 Feb 1994
1 April 1994
Average
100 m
800 rn
100 m
800 m
100 m
800 m
100 m
800 m
10.80 a
0.56 a
2.79 a
78.70 a
4.53 a
0.56 a
0.49 a
14.60 a
84.70 a
5.80 a
9.65 b
0.46 b
2.77 a
79.77 a
4.98 a
0.48 ab
0.45 a
13.50 b
86.23 b
6.38 b
9.60 b
0.47 b
2.87 a
80.10 b
4.19 a
0.55 a
0.49 a
13.60 cb
86.00 cb
6.32 cb
8.71 c
0.40 b
2.96 ab
81.65 c
5.04 b
0.44 b
0.46 a
12.7 d
87.18 d
6.83 d
8.20 d
0.31 cb
3.09 b
80.40 b
5.18 bc
0.47 a b
0.49 a
12.31 e
87.5 e
7.09 e
8.00 d
0.39 b
3.18 bc
81.80 c
5.24 c
0.50 a b
0.49 a
12.33 e
87.59 e
7.1 e
9.50
0.45
2.90
79.76
4.60
0.52
0.49
13.50
86.06
6.40
8.76
0.42
2.90
81.10
5.08
0.47
0.46
12.84
87.00
6.77
Means with Ithe same letter within each row are not significantly different with multiple comparison Duncan test
( P = 0.05).
Fatty acids.
' Ratio of unsaturated to saturated fatty acids.
Y M Mousa e t a1
ACKNOWLEDGEMENT
The authors extent their gratitude to Mr Ch Petrakis
and G Naxakis for their valuable laboratory assistance.
REFERENCES
American Oil Chemist's Society 1978 OSficial and Tentatiue
Methods. American Oil Chemist's Society, Champaign, IL,
USA.
Andrikopoulos K N, Hassapidou N M, Manoukas A G 1989
The tocopherol content of Greek olive oils. J Sci Food
Agric 46 503-509.
Boatella R 1975 Analysis of the tocopherols of vegetable oils
by gas phase chromatography. J Ann Chromatogr 27 163167.
Carlsson D J, Suprunchuk T, Wiles H M 1976 Photooxidation of unsaturated oils. Effect of single oxygen quenchers. J
Amer Oil Chem SOC53 656-695.
Chimi H, Sadik A, La Tutour A, Rahmani M 1988 Cotribution a I'etude comparative des pouvoirs antioxidants dans
I'huile d'olive du tyrosol de I'hydrotyrosol, de I'acide
cafeique, de l'oleuropeine et du BHT. Rev Fr Crops Gras 35
339-344.
Cimato A 1990 Effect of agronomic factors on virgin olive oil
quality. Oliuae 31 20-31.
Donaire J P, Sanchez J, Lopez Gorge J, Recalde L 1975 Metabolic changes in fruit and leaf during ripening in the olive.
Phytochemistry 14 1167-1 169.
Dugan L R 1961 Development and inhibition of oxidative
rancidity of foods. Food Techno1 15 10-15.
Fedeli E 1977 Lipids of olives. Prog Chem Fats Lip 15 57-62.
Fernandez-Diez M J 1971 The olive. In: The Biochemistry of
Fruits and their Products (Vol 2), ed Humle A C . Academic
Press, London, UK, pp 255-431.
Fontanazza G 1988 Growing for better quality oil. Olioae 24
12-18.
Interesse F S, Ruggier P, Vitagliano M 1971 Autoxidation of
olive oil: influence of chlorophyll pigment. Indust Agrar 9
318-324.
International Olive Oil Council 1991 Norme Comercial Internationale Applicable aux Huiles d'Olive et aux Huiles de
Grignons d'Oliue (COI/T. 15 INC no 1, rev 2). IOOC Publications, Madrid, pp 14.
Kiritsakis A 1991 Olive Oil. American Oil Chemist's Society,
Champaign, IL, USA.
Kiritsakis A, Markakis P 1984 Effect of olive collection
regime on olive oil quality. J Sci Food Agric 35 677-681.
Kiritsakis A, Markakis P 1987 Olive oil, a review. Adu Food
Res 31 453-482.
Kiritsakis A, Tsipeli A 1992 Hydrolysis and oxidation of olive
oil during the time that olive fruit remain on the tree. Riu
Ira1 Sost Gras 69 16-19.
La Notte E, Romito N 1972 Autoxidation of olive oil: effect of
polyphenols. Oleic Inter 53 111-123.
Maestro Duran A 1990 Relationship between the composition
and ripening of the olive and quality of the oil. Acta Hort
286 453-456.
Naudet M 1965 Dosage des acids oxies dans les huile d'olive.
Inform Oleic Inter 31 119-127.
Osman M, Metzidakis I, Gerasopoulos D, Kiritsakis A 1994
Qualitative changes in olive oil collected from trees grown
at two altitudes. Riu Ital Sost Gras LXXl 187-190.
Tonolo G, Marzo S 1989 Determinazione della vitamina E
aggiunta e dei tocoferoli naturali negli olia di semi dietetici
via HPLC. Riu ltal Sost Gras LXVI 3-6.
Tsimidou M, Papadopoulos G, Boskou D 1992 Determination of phenolic compounds in virgin olive oil by
RP-HPLC with emphasis on UV detection. Food Chem 44
33-60.
Vaughn R M, Simpson K C, Chicester C 0 1961 Compounds
responsible for the colour of black ripe olives. J Food Sci 7
26-27.
Vazquez Roncero A 1978 Les poly phenols de I'huile d'olive et
leur influence sur les characteristiques de l'huile. Reu Fr
Crops Gras 25 25-26.
Документ
Категория
Без категории
Просмотров
4
Размер файла
459 Кб
Теги
691
1/--страниц
Пожаловаться на содержимое документа