Olive olives

General information on olives

Olives are a typical food of the Mediterranean Diet and their consumption occurs by eating both the whole fruit and the condiment oil obtained from it.

The subspecies and the varieties of Olea europaea L. (olive) present on the world and Italian territory are numerous and produce olives that differ in: shape, size, color, season of maturation and type of destination for consumption.

The olives reach maturation in different periods depending on the variety, the early ones are ready for harvesting in October, while the late ones are extended until December or January; with maturation, the olives increase their percentage of lipids and reduce the water content; therefore, if the drupes are destined to the squeezing for the oil, it is FUNDAMENTAL to identify the right moment of the harvest (respecting the climatic variables, the techniques and timing of collection and conservation, etc.). For information on olive harvesting, see the dedicated article.

Curiosity: while in the autochthonous areas it constitutes a primary source of sustenance, in other geographical areas where it has been introduced, the olive tree is not equally appreciated; in Australia, for example, Olea europaea L. is a real weed.

Pasta alla Puttanesca

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Black olives are a characteristic ingredient of pasta alla puttanesca

Olive tree, the olive tree

Olives are the fruits (drupes) of the Species Olea europaea L., Genea Olea and family Oleaceae (also called olive ). It is a native evergreen tree of the Mediterranean basin, of Africa and Asia, which over the centuries has also been exported elsewhere; has specific characteristics based on the variety, but the latter are more or less common to:

1. Short and stocky stem that does not exceed 8-15m in height (except for Pisciottana, typical of the Campania region, which exceeds 15m in height).
2. Leaves green or silvery, elongated and between 1 and 3 cm long
3. White flowers
4. Fruit consisting of small drupes commonly known as olives; these are green in an unripe state but, as ripeness occurs, they darken tending to purple to become totally black.

WARNING! The black table olives present on the market boast such a dark color that they seem almost INNATURAL; indeed the appearance does not deceive! These are artificially colored drupes using chemical substances such as ferrous sulfate (the salt of hydrogen sulphide).

Parasites of olives and olives

The most harmful multicellular parasite for olives is the Dacus oleae, which lays the eggs in the drupes just before ripening making them inedible; on the other hand, the Black scale bug (a cochineal) and the Curculio nucum ( also called the curculus ) are also harmful. These organisms can be fought both with pesticides and with integrated or biological control.

The Olea europaea L. can suffer the negative effect of some fungi, among which we remember the Oleaginum cycloconium, while in the group of bacteria the most harmful is the Pseudomonas savastanoi pv. Oleae .

Olive subspecies

As we have said, there are numerous subspecies and varieties of O. Europea L. and, for disclosure correctness, below we will list only the most known subspecies; on the contrary, we will omit the distinction of small varieties. Obviously, all these varieties produce olives with slightly different morphological-chromatic characteristics.

The most common subspecies are:

• Olea europaea subspecies europaea, typical of the Mediterranean basin
• Olea europaea cuspidata subspecies, typical of South Africa, eastern Africa, Arabia and southwestern China
• Olea europaea guanchica subspecies, typical of the Canary Islands
• Olea europaea subspecies cerasiformis, typical of Madeira
• Olea europaea subspecies maroccana, typical of Morocco
• Olea europaea subspecies leperrinei, typical of Algeria, Sudan and Nigeria.

Olive tree structure

The olives have the typical structure of the drupe, therefore they are composed of:

1. Petiole with which the olive remains bound to the plant until the fall / harvest
2. External epicarp (the peel, outside of which there is a protective wax that hinders dehydration of the fruit)
3. Intermediate mesocarp (the pulp of the olives containing the lipid vacuoles in turn protected by some enzymes)
4. Endocarpus or hazel, that is the means of proliferation of the European Oleacea L .; this, in turn, has a well-defined stratification:
1. Woody and wrinkled external coating (visible portion of the endocarp)
2. Seed "properly so called" which contains other triglycerides, which can be extracted in the production of oil; however, the dressing fat obtained from the seeds is not qualitatively comparable to the product obtained from the pressing of the mesocarp. The seed is also known as olive almond and is composed of:

• Endosperm (outermost)
• Episperm (intermediate)
• Embryo (more internal).

The yield of olives for oil production is on average around:

• 60-70kg of must, composed of 1/3 of oil and 2/3 of vegetation water
• 30-40 kg of pomace

from which 17-18 liters of oil (about 20%) will be extracted indiscriminately. NB . As well as the percentages shown in the figure, the yield of the olives varies significantly in relation to the different qualities of O.europea L. and the production season.

Composition of ripe olives

Element / molecule	Quantity
water	40.0 to 50.0%
Oil	15.0 to 36.0%
Nitrogen substances	1.5-2.0%
Non-nitrogenous compounds	18.0 to 24.0%
fibers	5.0-8.0%
Ashes	1.0-2.0%

Looking at the olive composition table, we can notice a certain range in the percentages of the molecules / elements; this variability is due to various factors such as: the European O. L. variety, the level of ripeness of the olives, the endemic and annual climate, the composition of the soil and the cultivation techniques. In particular, there are notable differences between the varieties of olives chosen for the oil (more fat) and those for the production of olives are table (richer in water).