HISTORY OF OLIVE OIL

Olive oil is one of the oldest natural ingredients in the world. Its history goes back almost 8,000 years to when the first trees were cultivated in the Syrian/Iranian region of the Middle East.
Olive oil, like wine, offers a wide range of flavours, colours and aromas that vary with the nature of the soil and climate where the olives are culitivated and type of olive used.
Olive oil is the only cooking and salad oil that offers a variety of natural flavours. These can vary from bland to peppery and can be described as mild (delicate, light and almost buttery tasting), semi-fruity, fruity, pizzico (oil with a peppery accent), rustic (hearty oil) and sweet.
Colours can range from delicate straw hues to emerald green. While dark intense colour may signal a fruity flavour and lighter colours may indicate a nuttier flavour, this is not always the case since oils are often blends of several varieties of olives. Like wines, olive oils have vintages caused by changes in growing conditions that affect colour and flavour.
Olive oils differ in quality, smokepoint, colour, flavour and aroma. Each type of olive oil has its own purpose. Genuine extra-virgin oil has the richest, deepest flavour and captures the essence of the olive itself, but isn't appropriate for every dish. Save it for salads and other cold dishes or trickle it over hot dishes just before serving so the rich flavour can be fully enjoyed. Use it in dishes such as pasta with oil and garlic, where it is the featured ingredient. Use milder oils in dishes where the flavour will be dominated by other ingredients. Their lighter nature allows the flavours of the food to come through, and they are usually preferred for sauteing and frying.
Source: The Mediterranean Olive Oil Cook Book. By: Louise Steele

DEFINITIONS & TYPES OF OLIVE OIL

Olive oil is the oil obtained solely from  the fruit of the olive tree (Olea europaea L.), to the exclusion of oils  obtained using solvents or re-esterification processes and of any mixture with  oils of other kinds. It is marketed in accordance with the following  designations and definitions:
Virgin olive oils are the oils obtained from the fruit of the olive tree solely  by mechanical or other physical means under conditions, particularly thermal  conditions, that do not lead to alterations in the oil, and which have not  undergone any treatment other than washing, decantation, centrifugation and  filtration.
Virgin olive oils fit for consumption as they are include:
Extra  virgin olive oil:virgin  olive oil which has a free acidity, expressed as oleic acid, of not more than  0.8 grams per 100 grams, and the other characteristics of which correspond to  those fixed for this category in this standard
Virgin  olive oil:virgin olive oil which has a free  acidity, expressed as oleic acid, of not more than 2 grams per 100 grams and  the other characteristics of which correspond to those fixed for this category  in this standard.
Ordinary  virgin olive oil:virgin  olive oil which has a free acidity, expressed as oleic acid, of not more than  3.3 grams per 100 grams and the other characteristics of which correspond to  those fixed for this category in this standard.1/.
Virgin olive oil not fit for consumption  as it is, designatedlampante virgin olive  oil, is virgin olive oil which has a free acidity, expressed as oleic acid,  of more than 3.3 grams per 100 grams and/or the organoleptic characteristics  and other characteristics of which correspond to those fixed for this category  in this standard. It is intended for refining or for technical use.
Refined  olive oilis the olive oil obtained from virgin  olive oils by refining methods which do not lead to alterations in the initial  glyceridic structure. It has a free acidity, expressed as oleic acid, of not  more than 0.3 grams per 100 grams and its other characteristics correspond to  those fixed for this category in this standard. 2/.
Olive  oilis the oil consisting of a blend of  refined olive oil and virgin olive oils fit for consumption as they are. It has  a free acidity, expressed as oleic acid, of not more than 1 gram per 100 grams  and its other characteristics correspond to those fixed for this category in  this standard.3/.
Olive-pomace  oilis the oil obtained by treating olive  pomace with solvents or other physical treatments, to the exclusion of oils  obtained by re-esterification processes and of any mixture with oils of other  kinds. It is marketed in accordance with the following designations and  definitions:
Crude olive-pomace oilis olive pomace oil whose characteristics  correspond to those fixed for this category in this standard. It is intended  for refining for use for human consumption, or it is intended for technical  use.
Refined olive pomace oilis the oil obtained from crude olive  pomace oil by refining methods which do not lead to alterations in the initial  glyceridic structure. It has a free acidity, expressed as oleic acid, of not  more than 0.3 grams per 100 grams and its other characteristics correspond to  those fixed for this category in this standard.4/
Olive pomace oilis the oil comprising the blend of  refined olive pomace oil and virgin olive oils fit for consumption as they are.  It has a free acidity of not more than 1 gram per 100 grams and its other  characteristics correspond to those fixed for this category in this standard.5/  In no case shall this blend be called olive oil.
1/ This  designation may only be sold direct to the consumer if permitted in the country  of retail sale. If not permitted, the designation of this product shall comply  with the legal provisions of the country concerned.
2/ This designation may only be sold direct to the consumer if permitted in the  country of retail sale.
3/ The  country of retail sale may require a more specific designation.
4/ This  product may only be sold direct to the consumer if permitted in the country of  retail sale.
5/ The  country of retail sale may require a more specific designation.
Source: International  Olive Council

NUTRITION FACTS

POLYPHENOL COMPOUND PRESENT IN OLIVE OIL

A recent in vitro study showed that polyphenolic compounds present in olive oil, including oleuropein, inhibit the adhesion of monocyte cells to the blood vessel lining, a process that is involved in the development of atherosclerosis. In addition, when people with high cholesterol levels removed the saturated fat from their diets and replaced it with olive oil, their total cholesterol levels dropped an average of 13.4%, and their LDL cholesterol levels dropped by 18%. Note, however, that these benefits occurred when they used olive oil in place of other fats, rather than simply adding olive oil to a diet high in unhealthy fats.Three other recent studies (Valavanidis et al.; Morella et al.; Masella et al., see references below) suggest that such heart-healthy effects from olive oil are due not only to its high content of monounsaturated fats, but also to its hefty concentration of antioxidants, including chlorophyll, carotenoids and the polyphenolic compounds tyrosol, hydrotyrosol and oleuropein-all of which not only have free radical scavenging abilities, but protect the vitamin E (alpha-tocopherol) also found in olive oil.Greek scientists at the University of Athens reporting their research in the Journal of Agriculture and Food Chemistrybelieve the synergy of all these beneficial nutrients is what is responsible for olive oil's contribution to the health benefits of the Mediterranean diet, a hypothesis supported by Italian research published in the Journal of Nutrition.In this study, scientists found that the phenols in olive oil have very potent antioxidant effects. The protective effects exerted by extra virgin olive oil biophenols, namely, protocatechuic acid and oleuropein, against LDL oxidation included:

• completely preventing LDL's oxidation when placed in a medium containing macrophage-like cells (in the arteries, arteriosclerosis begins when macrophages damage LDL, starting the development of foam cells that infiltrate the lining of the artery and begin plaque formation)
• inhibiting the production of two powerful oxidants that would normally have been produced and would have damaged LDL, thus preventing the expected decrease in glutathione, a powerful antioxidant the body produces to disarm oxidants (also called free radicals)
• restoring to normal levels the protective activities of two free radical-disarming enzymes that contain glutathione: glutathione reductase and glutathione peroxidase
• inducing higher than normal production and activity of both of these glutathione-containing enzymes.

DURATION OF STORAGE

The acid value of an oil may be used as a measure of quality. However, the acid value of the oil must not be too high, as this denotes an excessively high content of free fatty acids, which causes the oil to turn sour. Discoloration may also occur. Olive oil should have an acid value of at most 2.0%.
Oils and fats spoil by readily becoming rancid. Rancidity is promoted by light, atmospheric oxygen and moisture and leads to changes in odor and taste.
Maximum duration of storage is as follows:

FRYING WITH OLIVE OIL

Frying is one of the few characteristics common to the entire Mediterranean area, be it European, Asian or African, and to the three religions practiced, Christian, Muslim and Jewish. It is one of the oldest methods in existence of cooking food.
Recent investigations have shown that frying is beneficial to the organism, particularly from the physiological point of view. Because of this, it has extended to areas where formerly it was not as popular. Whether the food fried is digested easily or lies heavily on the stomach depends to a great extent on the type of oil used, the temperature of the oil and the manner in which the food was fried. Studies undertaken on healthy subjects and patients with gastroduodenal problems (gastritis, ulcer, liver and biliary complaints) have shown that there is no relationship between food fried in olive oil and these illnesses.
The alteration undergone by vegetable oils when heated for frying is quicker and more fatty acids (seed oils), and the higher the initial acidity of the oil (it is more stable if it has a high content of natural antioxidants - vitamin E). This alteration also varies according to temperature and length of time heated, number of times used, manner of frying (in continuous frying it changes less), and the type of food being fried (frying fish, especially oily fish, increases the polyunsaturated acid content of the oil, facilitating its decomposition).
Olive oil is ideal for frying. In proper temperature conditions, without over-heating, it undergoes no substantial structural change and keeps its nutritional value better than other oils, not only because of the antioxidants but also due to its high levels of oleic acid. Its high smoking point (210ºC) is substantially higher than the ideal temperature for frying food (180ºC). Those fats with lower critical points, such as corn and butter, break down at this temperature and form toxic products.Another advantage of using olive oil for frying is that it forms a crust on the surface of the food that impedes the penetration of oil and improves its flavour. Food fried in olive oil has a lower fat content than food fried in other oils, making olive oil more suitable for weight control. Olive oil, therefore, is the most suitable, the lightest and the tastiest medium for frying.
It goes further than other oils, and not only can it be re-used more often than others, it also increases in volume when reheated, so less is required for cooking and frying.
The digestibility of heated olive oil does not change even when re-used for frying several times.
Olive oil should not be mixed with other fats or vegetable oils and should not generally be used more than four or five times.
The oil used for frying should always be hot; if it is cold the food will soak up the oil.
There should always be plenty of oil in the pan when deep frying. If only a small amount is used, not only will it burn more easily but the food being fried will be undercooked on top and overcooked on the bottom.

Frying temperatures

When heated, olive oil is the most stable fat, which means it stands up well to high frying temperatures. Its high smoking point (210º C) is well above the ideal temperature for frying food (180º C). The digestibility of olive oil is not affected when it is heated, even when it is re-used several times for frying.