Table of content A-Z

 

olive

 

Botanical name: Olea europaea


Olive

 

 

It is not exactly clear whether the olive tree stems from the Mediterranean region, as is widely supposed. It is also possible that it reached there from Central Asia. It is certain, however, that the olive tree has been one of the most important plants around the entire Mediterranean for about five centuries.

The olive tree is repeatedly mentioned in the Bible. The Romans used the fruits of the tree to extract oil, and the winners of the Olympic Games were honoured at the beginning with a wreath made of olive tree twigs; later this changed to a wreath made of laurel, or bay leaves.

Today, olives are still cultivated in the Mediterranean area, where they play an important role in the diet. Approximately half of all olive trees planted worldwide grow there.

 

Availability

Numerous different varieties are known, and they differ above all in flavour. They are harvested between November and January. In Germany pickled olives and olive oil are available all year round.

 

Appearance, taste, characteristics

Botanically speaking, the olive is a drupe, or stone fruit. When unripe it is green, and as it ripens it turns first purple and then black. The fruits are oval and about 2-3 cm long.

The flavour differs with the variety: olives can taste sweetish, sour, bitter or salty. In general, the green, unripe fruits taste bitter because of their oleuropein content and are cured with lye, brine, salt, or fresh water to minimize this bitter-tasting compound. The ripe olives can be pickled right away.

 

The greater part of the harvest is not sold fresh but is used for the extraction of olive oil.

In the various producing countries different varieties are cultivated. The most important of these are:

* Italy: Coratina, Ogliorola and Taggiasca

* France: Cailletier, Tanche

* Greece: Koroneiki

* Spain: Arbequina, Picual

 

A particularly fine black olive is the Greek variety Kalamata.

The variety Manzanilla is not only the most common olive grown in California but is also very popular worldwide. This is due to its high yield, the uniform fruits, and the comparatively easy handling. In addition, it yields a large amount of high-quality oil. On the other hand, the plants are more sensitive to cold and more susceptible to certain diseases than other varieties.

 

Ingredients

The olive pulp has a high fat content; it can be as much as 55% with small fruits, which are preferred for the extraction of olive oil. The fat contains large amounts of unsaturated fatty acids: on average 66% oleic acid, 12% linoleic acid, 9% palmitic acid, 5% eicosenoic acid and 5% palmitoleic acid.

 

The fatty-acid composition of olive oil corresponds roughly to the recommended intake of saturated, monounsaturated, and polyunsaturated fatty acids.

 

100 g contain:

 

Olives, black, fresh

Olives, black, pickled

Olives, green, fresh

Olives, green, pickled

Olive oil

Energy (kcal)

345

353

130

143

881

Water (g)

52

41

78

72

<1

Protein (g)

2.2

2.2

1.4

1.4

0

Fat (g)

36

36

13

14

97

Carbohydrates (g)

4.9

4.9

3

1.8

<1

Fibre (g)

3.8

3.8

4.4

2.4

0

Folic acid (µg)

45

45

50

50

0

Iron (mg)

1.6

1.6

1.6

1.6

<1

Saturated fatty acids (g)

5.3

5.3

1.9

2.1

14.7

Omega-3 fatty acids (g)

0.3

0.3

0.1

0.1

0.8

Omega-6 fatty acids (g)

3.1

3.1

1.1

1.2

8.6

 

Quality criteria, optimal storage conditions

The shelf life of pickled olives differs, based on whether they were prepared as whole fruits, cut into rings, with or without the stone, or crushed. Sealed jars can usually be stored for about a year; once they have been opened, the olives should be kept in the refrigerator and eaten within a few weeks.

 

Olives that have been bought at a market or at a greengrocery and were already kept there in open containers behind the counter are generally edible for up to 4 weeks if they are kept cooled.

There are many differences with regard to olive oils. The mass-produced goods of highest quality are 'extra virgin olive oil' or 'virgin olive oil'. If this designation does not appear on the label, then the oil has as a rule been heated or refined, i.e. it has been degummed, deacidified, bleached and steamed in order to purposely influence the flavour and colour.

A further difference between oils is the content of free fatty acids, which have a negative influence on the flavour and temperature stability. In extra virgin olive oil the maximum content allowed is 0.8%, in virgin olive oil it is 2%.

The highest quality oil is the so-called first drop oil, which is extracted by sedimentation. Such oils are found only in specialist shops.

In a tightly closed bottle, olive oil will keep for up to a year. Store the bottle in a cool place and at a constant temperature. Occasionally the oil in the bottle becomes turbid; this happens when the bottle has been stored at less than 10°C. This does not reduce the quality in any way; rather it is a natural process by which the ingredients of the oil become visible owing to the low temperature.

 

Presumed effect on health

The leaves of the olive tree are used medicinally to lower blood pressure. This effect is due to the phenolic compound oleuropein.

The fruits themselves are supposed to be effective for constipation and gallstones; black olives are easier to digest than green olives.

 

Form of consumption, use, processing, practical tips for preparation

Green olives are treated with lye, brine, salt or fresh water to extract the bitter-tasting compounds and also to improve the consistency of the pulp. This curing is not necessary with black olives, which can be processed right away.

 

To pickle olives the fruits are put in brine or subjected to lactic acid fermentation to achieve a more intensive flavour. Various herbs and spices can be added to the brine as desired, such as thyme, oregano, chili, garlic, rosemary, winter savory, bay leaves, fennel, lemon and coriander seeds.

It is easy to stuff olives yourself, or they can be bought in food shops; the most popular fillings are almonds and pimento peppers. Other possibilities are various pastes, for example of tuna or lemon grass.

 

Olives in brine are useful to enhance many dishes. They can be used for salads, Mediterranean fish and meat dishes, macaroni casserole, pizza and stuffing for chicken. In addition, delicious dips and pastes can be made from them that can be eaten with vegetables and bread; they can also be spread on roasts, serving as a crust.

In order to extract oil from the olives, they are cleaned within 24 hours after being harvested, freed of leaves and small twigs, and then ground. The ground mass is then pressed.

 

Hydraulic presses were used for this earlier, and led to the term 'cold-pressed olive oil', as no heat at all was used in the production. Meanwhile, centrifugal mills are predominantly used, which also deliver cold-pressed oil. The yield is much greater compared with that using hydraulic presses.

The temperature during pressing may not exceed 27°C; otherwise the oil may not be designated as cold-pressed.

 

Miscellaneous

Olive trees do not bear fruit until they are about 7 years old. The older the tree, the better the quality of the fruits. The highest quality goods come from trees that are approximately 100 years old, but the yield from such trees is decreased.

 

 

_________________________

 

  This article was written by

         

 


 

  With the website www.the-green-pantry.com the Fritz Terfloth Foundation of Münster offers consumers independent and competent information about plant foods and their health effects. All texts are subject to German copyright law. Information about the conditions for use of the texts by third parties can be found here.


Auf Ihrem System scheint kein FlashPlayer installiert zu sein oder es ist
ein Update des Players notwendig. Sie können den Player hier herunterladen: