From Progress in
New Crops, Proceedings of the Third National Symposium NEW CROPS: New
Opportunities, New Technologies
by Joan Tous and Louise Ferguson
Olive
The cultivated olive (Olea
europaea,
Oleaceae) is a long-lived, evergreen tree native to the Mediterranean
basin. It is valued for its fruit and oil. Mediterranean countries
account for around 95% of the world's olive cultivation (8,702,000 ha).
In the Mediterranean 90% of the olive trees are grown for the oil.
World olive oil production is currently increasing; the commercial crop
during 1990-1994 was 1,796,900 t (IOOC 1994), with the European
Community (EC) producing around 1,337,000 t (Spain 40%, Italy 33%, and
Greece 22%), Tunisia 194,000 t and Turkey 61,500 t of oil. World table
olive production in 1990-1994 was 954,500 t (IOOC 1994). Spain is the
world's largest producer (23%) and exporter of table olives, follow by
Turkey (12%), U.S. (11.4%), Morocco (8.5 %), Syria (7.5%), and Greece
(7.3%). In Australia, Chile, China, Mexico, New Zealand, and South
Africa, olives are considered a new crop.
The olive
oil and
table olive industries play an important role in the agricultural and
processing sectors of the major olive producing countries. Most olive
oil is consumed within the Mediterranean countries; only 18% of
production enters world trade. On average from 1988 through 1991 the
world olive oil marketed represented 6% of the quantity and 23% of the
value of the world trade in fluid edible oils (UNCTD 1993). To a large
extent olive oil does not compete with other vegetable oils but
occupies a specialty niche market.
The olive tree
has a wide
range of adaptability. It requires a mild climate with warm summers and
cold winters. The tree requires substantial chilling for good fruiting
(Martin et al. 1994), but is injured when temperatures fall below
-10deg.C. Olive is considered a drought-resistant species because it
thrives in areas where water stress is frequent: Mediterranean
climates. It has been postulated that the minimum water requirement for
olive is 2,000 m3/ha year, mainly during flowering and fruit setting in
late spring, and again in the summer as the fruit increases in size
(Tous 1990; Bongi and Palliotti 1994). Olive trees will grow on poor
soils and rocky hillsides, but deep soils produce the best quality
fruit. They tolerate saline or alkaline soils and those with a high
lime content. Their root system is relatively shallow, and will not
tolerate waterlogged soils.
Olives are wind
pollinated, thus
flowering during rain, high temperatures and dry wind conditions are
deleterious to good fruit set (Griggs et al. 1975). Mature olive trees
produce huge numbers of flowers, but the fruit set is normally below 5%
(Lavee 1986; Martin et al. 1994). Most olive cultivars will set some
fruit in a monocultivar culture. However, they benefit greatly from
cross-pollination (Lavee 1986). Olives are picked late in autumn or
winter, as the oil content and fruit characteristics change with
ripening. Olive cultivars usually fall into one of two commercial uses
(Jacoboni and Fontanazza 1981; Barranco and Rallo 1984; Tous and Romero
1993): "Oil" and "Table." "Oil" cultivars predominate. The most famous
are: 'Picual', 'Arbequina', 'Cornicabra', 'Hojiblanca', and 'Empeltre'
in Spain; 'Frantoio', 'Moraiolo', 'Leccino', and 'Pendolino' in Italy;
'Koroneiki' in Greece; 'Chemlali' in Tunisia; 'Ayvalik' in Turkey;
'Mission' in California and Australia, etc. The "table olive" cultivars
include 'Manzanilla' and 'Gordal' (syn. 'Sevillano' in California and
'Queen' in Australia) from Spain; 'Kalamata' from Greece; 'Ascolano'
from Italy; 'Barouni' from Tunisia, etc. Alternate bearing is a problem
with some cultivars.
Tree management of this crop
has undergone
many changes in recent decades including increased planting densities
(100 to 300 trees/ha), new methods of propagation, improved cultural
practices and mechanical harvesting, are some examples. Growth
regulators, such as naphthaleneacetic acid (NAA), are used for fruit
thinning to increase the fruit size and control the alternate bearing
in some table olive orchards (Lavee 1986; Martin et al. 1994). Olives
are propagated primarily by cuttings, truncheons or by budding seedling
rootstocks. The trees propagated by rooting semi-hardwood cuttings come
into bearing within three to four years after planting. The type of
harvest depends upon fruit use. Oil olives are harvested by hand or by
mechanically shaking the tree. Those for pickling must still be
harvested by hand as the fruit bruises easily. The major pest problems
are the following: olive fly (Dacus
oleae, mainly in the Mediterranean basin), black scale (Saissetia oleae),
olive leaf spot (Spilocaea
oleaginea), olive knot (Pseudomonas savastanoi),
and Verticillium dahliae.
Olives
are nutritious (Table 2),
the oil component includes unsaturated fatty acid (70% to 80% oleic
acid and 7% to 12% linoleic acid), and small amounts of polyphenols,
tocopherols, sterols, and many aromatic compounds (Mataix and Martinez
1988; Tous and Romero 1993).
Olive oil and table
olive
industries play an important role in the agricultural and processing
sectors of the major olive producing countries of the Mediterranean
basin. World olive oil production and exports are projected to increase
slightly in the next few years, while table olive production will
remain stable. While Italian olive oil production is expected to
stabilize or decrease, Spain, Tunisia, Morocco, and other countries
(Argentina, Australia) are expected to achieve substantial increases in
this crop (UNCTD 1993). In addition to culinary uses, olive oil, an
unsaturated fat, has recently become more valued for its health
benefits. Mainly for this reason, through the last decade the olive oil
consumption has increased in several non-Mediterranean countries (USA,
Australia, Japan, etc.).
Table
2. Nutritional composition of Mediterranean crops (per 100 g of edible
portion). Source: Goulart (1980); Sawaya et al. (1983); Fernandez Diez
(1983); IBPGR (1986); Morton (1987); Cantwell (1994).
| Crop/Product |
Olive (ripe
pulp) |
Mandlarin |
Fig, fresh |
Fig, dried |
Persimmon |
Pomegranate
(pulp) |
Pistachio
nut |
Carob flour
| Cactus pear
(fruit pulp) |
Loquat |
| Water
(%) |
70.8 |
87.0 |
78.0 |
23.0 |
79.0 |
82.3 |
5.3 |
11.2 |
85.0 |
86.5 |
| Cal. |
163 |
45 |
80 |
274 |
77 |
65 |
594 |
180 |
38 |
168
|
| Protein
(g) |
1.2 |
0.8 |
1.3 |
4.3
| 0.7 |
0.9 |
19.3 |
4.5 |
0.5 |
1.4
|
| Fat
(g) |
18.6 |
0.1 |
0.3 |
1.3 |
0.4 |
0.3 |
54.0 |
1.4 |
0.1 |
0.7 |
| Carbohydrates |
| Total
(g) |
-- |
13.0 |
20.3 |
69.0 |
19.6 |
16.4 |
19.0 |
80.7 |
11.0 |
43.3
|
| Fiber
(g) |
1.7 |
0.5 |
2.0 |
5.6
|
1.2 |
0.3 |
2.2 |
7.7 |
1.8
| 0.9 |
| Ash
(g) |
2.1 |
0.3 |
0.6 |
126 |
-- |
0.5
| 2.7 |
2.2 |
1.6 |
--
|
| Minerals |
| Ca
(mg) |
79 |
30
| 50 |
77 |
6 |
3 |
131 |
352 |
60 |
70 |
| P
(mg) |
19 |
23 |
22 |
3.0
| 26 |
8 |
500 |
81 |
34 |
126 |
| Fe
(mg) |
0.9 |
0.4 |
0.6
| 34 |
0.3 |
0.7 |
7.3 |
5.0 |
0.8 |
1.4 |
| Na
(mg) |
760 |
5 |
2 |
640 |
6 |
3 |
-- |
-- |
0.8 |
-- |
| K
(mg) |
48 |
140 |
194 |
100 |
174 |
259 |
972 |
950 |
161 |
348
|
| Vitamins |
| A
(IU) |
200 |
30 |
80 |
0.10 |
2710 |
Tr |
230 |
50 |
40 |
2340 |
| Thiamine
(mg) |
0.01 |
0.08 |
0.06 |
0.10 |
0.03 |
0.02 |
0.70 |
0.03
| 0.01 |
--
|
| Riboflavin
(mg) |
0.18 |
0.03 |
0.05 |
0.10 |
0.02 |
0.03 |
0.20 |
0.05 |
0.02 |
-- |
| Niacin
(mg) |
0.1
| 0.2 |
0.4 |
0.7 |
0.2 |
0.3 |
1.4 |
2.5 |
0.3 |
-- |
| Ascorbic
acid (mg) |
3 |
45 |
2 |
0 |
15 |
4 |
0 |
-- |
30 |
3 |
Last update August 22, 1997 aw
|
|