PROCESSING TABLE OLIVES

The olive fruit has a bitter component (oleuropein), a low sugar content (2.6-6%) compared with other products (12% or more) and a high oil content (12-30%) depending on the time of year or variety. These characteristics are what make it a fruit that cannot be consumed directly from the tree, since it has to undergo a series of processes that differ considerably from region to region, and which also can depend on variety.

Some olives are, however, an exception to this rule because as they ripen they sweeten right on the tree, in most cases this is due to fermentation. One case in point is the Thrubolea variety in Greece.

The olive's suitability for table consumption is a function of its size, which is important to presentation. Olives between 3 and 5 g are considered medium sized, while those weighing over 5 g are large. Fruits that are more or less spherical in shape, usually have the best market, although some elongated ones also find favor. The stone should come away easily from the flesh and a flesh: stone ratio of 5 to 1 is acceptable; the higher this ratio the better the commercial value of the olives. The skin of the fruit should be fine, yet elastic and resistant to blows and to the action of alkalis and brine. A high sugar content in the flesh is an asset. The lowest acceptable percentage is 4% especially in olives that undergo fermentation. Oil content should be as low as possible because in many cases it impairs the keeping properties and consistency of the processed fruit. Only in certain types of black olives is a medium to high oil content desirable.

GREEN OLIVES

Green olives are obtained from olives harvested during the ripening cycle when have reached normal size, but prior to color change. They are usually hand picked when there is a slight in hue from leaf -green to a slightly yellowish green and when the flesh begins to change consistency but before it turns soft. Color change should not have begun. Trials have been run to machine-harvest table olives, but owing to the high percentage of bruised fruit they have to be immersed in a diluted alkaline solution while still in the orchard. Recently harvested, the olives are taken to the plant for processing on the same day if possible.

BLACK OLIVES IN BRINE

This is a typically Greek preparation using the Conservolea variety which grades at some 200 olives per kilogram. The fruit is picked when ripe but before overripening begins and before the olives shrivel from frost. They have to be transported as quickly as possible to the processing plant where they are sorted, washed and immersed in a brine solution at a concentration of 8%. Large-scale plants use big 10-20 ton vats, while small-scale processors use wooden vats.

At the start of fermentation the olives must be prevented from coming into contact with air and the vats are covered and made airtight. The brine stimulates the microbial activity for fermentation and reduces the bitterness of oleuropein. It drops to a concentration of 6% which makes it necessary to increase it to 8 or over 10%, homogenizing it by operating a plump that

activates circulation. These are packed in vinegar (25% of the volume of the brine) and even under heat treatment: a few grams of the oil are then added to each can to form a surface layer.

KALAMATA OLIVES

Another variation is the Kalamata type, which uses olives of this variety in Greece. The difference is that incisions are made in the fruit to facilitate washing with water or brine, which proceeds rapidly owing to the low oleuropein content of the variety. The olives are immersed in wine vinegar for one or two days and are packed in fresh 6% or 8% brine with pieces of lemon. Olive oil is often added to form a surface film. These olives are highly rated for they flavor.