Posts Tagged ‘Green Olives’

Focus on: Table Olives

Table olives are defined as ‘the sound fruit of specific varieties of the cultivated olive tree harvested at the proper stage of ripeness and whose quality is such that when they are suitably processed as specific in this standard, produce an edible product and ensure its good preservation as marketable goods. Such processing may include the addition of various products or spices of good table quality.’

Table olives are prepared from good quality fruits from the cultivated olive tree (Olea europaea L.). Table olive production was initially restricted mainly to the region around the Mediterranean Sea, but has now spread to both North and South America and even Australia. The world production of table olives is approximately 1.7 – 1.8 million tonnes with the main producers being the European Union, Turkey, Egypt, Syria, and Morocco. The United States of America and Argentina are also significant producers. Within the EU Spain is the main producer followed by Greece and Italy.

Olives have become an increasingly popular part of the UK’s diet and are widely available in delicatessen counters, supermarkets, farmers markets and restaurants across the country, but there remains very little knowledge about this product.

Olives are one of the few fruits that cannot be enjoyed in their raw state. Any romantic idea you might have of wandering through a sun soaked olive grove and picking and sampling olives are best left in your imagination – if you did decide to sample an olive directly from the tree you would be left with a very bitter taste in your mouth! The olive fruit has a bitter component and a low sugar content of between 2.6-6% when compared with other fruits that usually have 12% sugar or more. They also have high oil content of anywhere between 12-30% depending on the time of harvest and the variety of olive. This mix of characteristics means that the olive is a fruit that cannot be eaten in its natural state. Fresh raw olives are tough and contain a glycoside called oleuropein, a chemical compound that is concentrated in the olive’s skin making the olive extremely bitter and unpalatable. In order to make the olive pleasant to eat it has to undergo a series of processes to remove the bitter oleuropein. The processes used depend on the type of olive and the local methods and customs and it could be said that there are as many processing methods as places where olives are consumed. In an attempt to normalize the different products, the International Olive Council has a Trade Standard Applying to Table Olives (IOOC, 2004a), in which the types, trade preparations, quality factors, and other properties are described. In basic terms the fruit is generally either treated in sodium, potassium hydroxide, or brine or rinsed continuously in water. There are some exceptions to the rule, such as the Thrubolea olive from Greece, which can ripen and sweeten on the tree and there a very few varieties that are sweet enough to be eaten after sun drying.

Traditional curing methods require months and include:

• Brine-curing: soaking in brine for one to six months
• Oil-curing: soaking in oil for several months
• Dry-curing: packing in salt for one or more months
• Water-curing: soaking, rinsing and re-soaking in plain water, this method is the slowest of all and consequently is rarely used

Each olive-growing country has its own typical olive varieties. Of all the olive varieties that exist, only those having suitable characteristics are used for table olive processing, and even fewer varieties are used for industrial preparation and international trade. At the international trade level, the most important table olive varieties are Manzanilla, Gordal Sevillana, Hojiblanca, Kalamata and Conservolea, and to a lesser extent Bella de Cerignola, Ascolana Tenera, and Picholine.

The suitability of olives for table consumption depends on:

1. .   Size: olives weighing between 3 and 5 grams are  ‘medium-sized’, over 5 grams they are ‘large’
2. .   Shape: a more or less spherical shape helps facilitate processing operations although some elongated fruits are also popular
3. .   Flesh-to-stone ratio: the higher it is the better the commercial value, 5:1 is acceptable
4. .   Flesh finesse
5. .   Taste
6. .   Firmness: the skin of the fruit should be fine, yet elastic and resistant to blows and to the action of alkalis and brine
7. .   Ease of stone detachment: the stone should separate easily from the flesh

Olives tend to have maximum oil content (about 20-30% of fresh weight) and reach their greatest weight six to eight months after the blossoms appear. At that stage they are black and will continue to cling to the tree for several weeks. Fruits are allowed to mature to different levels for a range of flavours and characteristics, and are picked or shaken off the tree at the appropriate stage of ripeness. The fresh olives are then cured using methods including salting, fermentation and/or acidification, rendering them less bitter and giving them their telltale saltiness, texture and flavour. Table olives are usually green or black and the colour, texture and flavour of the olives depends on the curing medium (usually lye, brine, or salt) and the degree of ripeness when they are picked (green olives are picked while unripe which makes them denser and more bitter than brown or black olives which stay on the tree until fully ripened). The Classification of the fruit and the method of processing are determined by the ripeness of the fruit and the colour of the final product. Four fundamental types have been established:

Green olives: Fruits harvested during the ripening period, prior to colouring and when they have reached normal size. Once processed, a green olive’s colour may vary from green to straw yellow. Green olives are usually soaked in a soda solution to remove the bitter taste and washed repeatedly in clean water before being packed in brine and offered for sale. Green olives are also the most likely to be marinated and stuffed with a range of fillings including garlic, pimento, or almonds

Turning-colour olives: Fruits harvested before the stage of complete ripeness is attained, at colour change. After processing, this type of olive may vary from pink to rosé wine or brown.

Naturally black olives: Fruits harvested when fully ripe, or slightly before full ripeness is reached. Once processed black olives may range from reddish black to deep violet, greenish black, or deep chestnut. Black olives are fully ripe and have high oil content, a mellow flavour and soft flesh. The most common way to prepare these olives is to wash them and then preserve them in brine.

Black olives: Fruit that is harvested during the turning colour stage and are later blackened through oxidation in an alkaline solution