Dr. Rosario Franco, Agricultural Promoter,

Specialized in Olive-growing for the Regional Agency ARSSA,

     Oil taster expert. Panel Leader.

< INTRODUCTION  [ Top ]

The origin of olive oil goes back to ancient times, and runs parallel with the origins of Mediterranean civilizations. Even though it seems that olive oil has its origins in Asia Minor the area of primary diffusion was the Mediterranean basin.

Today olive cultivation has been exported beyond the Mediterranean borders finding fertile lands in California, Mexico, Peru, Chile, Argentina, and also in South Africa and Australia.

The olive tree and its fruit have always deeply influenced the peoples of the Mediterranean basin, and it has always been interlaced with other areas of life such as religion, diet, culture and art, the traces of which are still very visible today. The olive tree and its oil are tied to each other like bread and wine, to our peasant civilization rich in traditions and profoundly different from the lifestyle of our age. Olive oil is the only vegetable oil obtained from fruit and not from seeds. The olive is the fruit of the olive tree and it is identified in botanical terms as drupe, that is, a fruit with a pulpy external part and a solid internal part known as a nut. The proportions between the different components of the drupe and the colour of the epicarp vary according to the variety.

The part mainly concerning the oil industry is the mesocarp, in which cells containing percentages of oil drops varying from 14% to 30% are preserved in large vacuoli.

Of course, along with these fatty substances there is a large proportion of water (70-75%), there are sugars (3-5%), polysaccharides (3-6%), pectic substances (1.5%), proteic nitrogen (1.5%), organic acids (4-6 %), and numerous other minor components amongst which the glucoside called oleuropein is worthy of mention because it makes the pulp fresh and taste very bitter.

The olive tree is a rustic plant that has adapted to different types of climates. Through time this has generated the selection of particular varieties whose special characteristics have been identified and spread through propagation, that is to say, not by using the seed but a piece of the plant itself, thus obtaining a series of perfectly identical and uniform plants compared to the mother plant (cloning).

The olive tree serves as an illustrative model of our peasant people’s labour: despite being a very rustic plant and easily adaptable to the worst of climatic and soil conditions, cultivating it requires great professionalism, especially if one aims to optimize its production.

< THE ORIGIN OF OLIVE OIL  [ Top ]

According to ancient legends that attributed magical and divine explanation to any human event and reality, it was Athena who created the olive tree. According to the legend zeus, decreed that Earth was going to be donated to whoever amongst the Gods was able to give the most useful gift to mankind. Athena ordered Earth to produce a new and wonderful tree and in that moment the olive tree was born.

The legend is fascinating but a little unkind towards Asia Minor. Indeed, the legendary olive tree and the oil extracted from its fruit have accompanied the history of mankind. Eight thousand years ago the olive tree was already being cultivated in the Middle East and the first harvests were probably gathered in Syria or Crete. Following this, the Phoenicians spread olive cultivation to the whole of the African and Southern European Mediterranean coasts.

With the Greeks the cultivation of olive trees rapidly grew, but the Romans were the people who cultivated these multipurpose fruits in each and every territory they conquered (in some cases neglecting the existing cultivation in Southern Italy). In many cases the Romans ordered the conquered peoples to pay their dues in the form of olive oil. And again the Romans were the first to build olive pressing tools and to perfect the oil preservation techniques.

The olive tree has always been considered a holy tree by all civilizations emerging in the Mediterranean basin, and the oil extracted from its fruits was not only used as food but also for religious and ritual purposes. The Egyptians considered it a gift of the Gods, the Phoenicians spread it through their commerce and defined it as "liquid gold", the Greeks and the Romans used it for medical purposes and as fuel in votive lamps, whilst the Jews utilized it to "anoint" their King, and the Christians used it from the beginning in their most significant rituals.

Since the beginnings of the olive tree and its fruit, it has been an ever present part of man’s history for us in both holy rituals and daily life: indeed, oil is not only used to flavour food dishes but also for massages and cosmetics. In Homeric poems oil was uniquely used for cleaning and hygiene. The Ancient Romans classified olive oil into five levels of quality:

1. "oleum ex albis ulivis" from pressing green olives,

2. "oleum viride" from olives harvested at a later stage of ripening,

3. "oleum maturum" from ripened olives,

4. "oleum caducum" from olives fallen to the ground, and

5. "oleum cibarium" from almost withered olives that were used for feeding slaves.

According to the traditional diet, olive oil represents one of the basic products of Mediterranean agriculture with its undisputed nutritional value brought about by its chemical composition, and its organoleptic characteristics exalted by its use as seasoning.

Even at the dawn of the third millennium, olive oil is a product full of mysticism and is the main fundamental component of the now celebrated Mediterranean diet, a fashion certified by many experts because of its health benefits.

< OIL COMPOSITION  [ Top ]

Olive oil is chemically almost completely made up of triglicerides (98-99.5%), glycerin esters with fatty acids, the average composition of which is represented by saturated fatty acids (about 16%, amongst which the palmitic prevails), monounsaturated fatty acids (about 75% with a net predominance of the oleic acid) and polyunsaturated fatty acids (about 9% with predominance of linolenic acid and limited quantities of linoleic).

In addition to these main components, olive oil contains other compounds that make up the unsaponifìable fraction and, even though present in minimum quantities (0.5-2%), decisively effect the product’s nutritional and organoleptic quality (sterols, aliphatic and triterpenic alcohols, polyphenols, tocopherols, components of the aroma...).

Olive oil is an alimentary fat and therefore it is not surprising that it is composed of  98% fat substances that have a mainly energetic function. This product presents marked nutritional value and health benefits for man, partially provided by the nature of the fat component, and in part by the inherent characteristics of a small percentage of compounds (about 2%) that represent "the fingerprint" of each olive oil.

Some of its substances therefore have a therapeutic value, others represent the main part of the aromatic bouquet of the oil (fragrances-flavours), yet others are efficient natural antioxidants that can give the product its preservative qualities. All of them contribute to making extra virgin olive oil different from all other oils of vegetable origin. Summarizing its numerous compounds (more than 220) in groups, we will briefly describe the characteristics of each.

HYDROCARBONS: Squalene is the hydrocarbon with the highest proportion (65%), and a precursor of cholesterol.

STEROLS: Beta-sitosterol prevails in olive oil, a substance that can oppose the intestinal absorption of cholesterol.

PIGMENTS: (Chlorophyll A and B and carotenoids): The chlorophylls are the pigments providing the green colour to the freshly extracted oil, which encourage oxidation of the oils in the presence of light, thereby degrading it. However, in the dark, together with the phenols, they protect against the oxidative phenomena. Among the carotenoids, particular importance is given to beta-carotene as a precursor of vitamin A.

ALCOHOLS: aliphatic alcohols are found, along with triterpenic alcohols which are an intermediary for the sterols formation.

ALDEHYDES, TERPENES, ESTERS, KETONES, etc.: They are products of the secondary meta-bolism and influence the oil’s aromatic features which have an influence in its hedonistic evaluation.

PHENOLIC COMPOUNDS: The antioxidant power of polyphenols, in addition to their biological value, is now widely established in the literature. Among vegetable fats, virgin olive oils are the only ones possessing the remarkable natural quantities of polyphenols (50-500 mg/Kg). In summary it can be said that polyphenols:

1) Protect the fatty acids from oxidative phenomena.

2) Perform an anti-oxidant action, which is translated into a protective effect against degenerative phenomena of various natures, especially the pathologies caused by a great presence of free radicals in the organism.

3) With time contribute to maintaining the olive oil’s stability, thus protecting the product from oxidative degeneration processes and therefore safeguarding the oil’s nutritional quality.

TOCOPHEROLS: Contemporaneously perform important biological and antioxidant functions. Alfa-tocopherol, better known as vitamin E because of its antioxidant properties, is 90% of the tocopherol component; whilst gamma-tocopherol primarily performs antioxidant activity inhibiting the product’s rancidity process.

< OLIVE OIL CLASSIFICATION  [ Top ]

Chemical physical parameters

In order to protect consumers of olive oil, the EEC approved a two Council Directives (2568/91 and nr 1959/03) which attempt in the best way possible the multitude of oil products, in terms of their quality classes and so how they should be placed on the market. Fortunately the consumer has only to choose among a few of them.

The oil that represents the best product on the market is the extra virgin olive oil as it is directly obtained from the mechanical pressing of the olives and should have specific sensory and chemical-physical characteristics, regulated by the directive, before reaching the market. Extra virgin olive oil, being oil which is obtained mechanically without any chemical processing, should have under 0,8% acidity (the lower the acidity the finer the oil).

But the actual personality of extra virgin olive oil is given by a set of other characteristics such as: fragrance, taste, transparency, fluidity, all of which define one product compared to another. The huge variety of flavours that olive oil can have make it a food suitable for any type of cuisine.

The first people to use it were of course the peoples of southern Europe who, thanks to their healthy Mediterranean diet, have the lowest cardio-vascular illness rate. Lovers and connoisseurs know that olive oil can be fruity, sweet or bitter, strong or delicate; its taste, indeed, being strongly determined by various natural factors. Therefore, as with wine, olive oil can vary greatly depending on the sun, the picking quality, the climate, and so on.

Oils obtained from the olive tree’s fruit by using only mechanical processes or other means of physical processing, and at controlled thermal conditions avoiding alteration of the oil, and that are not subject to any treatment other than washing, decanting, centrifugation and filtering, can be classified as follows:

Extra virgin olive oil: This is the best oil that can possibly be produced. It should not be subject to any manufacturing or refining process. It should have an organoleptic score equal to or higher than 6.5, and an acidity level below 0,8% (1 gram per 100 grams). All other characteristic must conform with the regulations currently in force;

Virgin olive oil:This oil’s acidity grade is approximately 2%, and the organoleptic score is equal to or higher than 5.5;

Virgin olive oil “Iampante”: This is olive oil with a maximum allowable acidity over 2% and an organoleptic score lower than 5.5;

Refined olive oil: Its acidity should not exceed 0.3%;

Olive oil: This is oil obtained from the blending of virgin olive oils with refined oils; its acidity should not exceed 1%;

Sansa oil: Obtained from the olive residues by means of treatment using solvents.

Refined sansa oil: Obtained from the refining of the sansa oil; its acidity should not exceed 0.3%;

Sansa-olive oil: Obtained from the blending of virgin olive oils with sansa oils; its free acidity should not exceed 1.0%.

It should be remembered that the above-illustrated EEC parameters are undergoing revision, this is largely aimed at better quality control. In spite of the diffusion of olive cultivation throughout the world, the use of olive oil seems to be limited to Mediterranean countries, while the mostly used oils in the rest of the world are made from peanut, rape, soya, sunflower and cotton seeds. We should, however, specify that technically the best oil for cooking and non-cooking uses is olive oil in all its various forms. The product classification of the oils, however, is not simple. In some cases ambiguousness in the names used can deceive the consumer.

< ORGANOLEPTIC PARAMETERS  [ Top ]

Nowadays the procedure usually used to assess the quality and excellence of an olive oil is the sensory method. Sensory analysis is a set of methods making the perceivable characteristics of a food product objective and measurable by means of using the sensory organs. The sensory analysis method and the logic procedure module followed during the various operations make the final definition objective: in our case, the organoleptic evaluation of the oils.

In practice, through the use of special glasses, a tester tastes the oil and makes a quality judgement by assigning a score to it. The senses of smell and taste are used in the delicate sensory tasting and evaluation phases.

The olfactory analysis is carried out by deeply inhaling the sample to be evaluated with both nostrils. The initial evaluation of the oil’s olfactory characteristics examines the fruity intensity that can be intense, light or average. In this phase you can also perceive possible defects or disagreeable odours. Finally, tasting defines the entire organoleptic profile.

To examine an oil correctly you need to take a small sip, and then inhale without swallowing, rotating it in the mouth to bring it into contact with all the taste and olfactory buds.

Generally speaking the sensory analysis of the oils is assigned to a group of properly trained people who gather to express a judgement. The tasting of extra virgin olive oils is a subject that is assuming an increasingly important role, since you can determine and define the characteristic parameter and the product class from the sensory assessment of the product, in agreement with the regulations in force.

In the last few years, consideration has been given to regulating the production and commerce of olive oil. Amongst other things, this has become a necessity in order to guarantee improvements in production and regulatory control of commercial exchanges in order to protect the consumer. After a series of legal directives, it was only through the above-mentioned directive n. 2568/91 that the European Community put some order into this delicate sector, both from the chemical and the organoleptic point of view.

We should opportunely specify that the above-mentioned directive introduced for the first time, as a quality parameter, the organoleptic evaluation of the oils according to a sensory analysis, that is, also taking in to consideration – a unique case in the history of food –  the olfactory, tasting and tactile characteristics in order to complete the analytical picture.

The introduction of the Panel test brought about the evolution of the oil quality concept. Until recent times extra virgin olive oil was confined to the simple role of traditional seasoning, mainly in the production areas. With the evolution of consumerism and markets it now represents a fundamental seasoning/food for every type of diet, for health and pleasure.

During recent years the market for extra virgin oil has been subject to deep changes, and so we went from generally plain and anonymous oils, to marketing very different products both commercially and perceptually. The sensory analysis defines the main attributes of an oil, both negative and positive.

NEGATIVE ATTRIBUTES

Morchia (sediment): The characteristic flavour of oil that has been in contact with decanting sediments in underground or above-ground tanks.

Riscaldo (warmth): Caused by the fermentation of olives which have been kept piled up for too long and so were subject to advanced anaerobic fermentation.

Moldy: A disagreeable smell caused by using olives in which mildew and yeast developed due to lengthy storage in humid warehouses.

Rancid: A very unpleasant flavour caused by oxidation resulting from heat or exposure to light or air. It can also be caused by the use of poorly cleaned containers.

Metallic: Easily recognized, it is caused by the use of unprotected or non-ionised ferrous machines.

Avvinato, inacetito (wine, vinegar): Tasting of wine or vinegar because the olive fermentation process causes the formation of acetic acid and ethanol.

Other Negative Attributes

Oxidized: The product that has been exposed to air for a considerable amount of time and thus has become rancid after reacting with oxygen. It is immediately recognisable and no longer fit for consumption.

Flat: Excessively bland and oily.

Mature: Describes a warm golden colour with a rotund body and fruity flavour leaning towards sweet.

Tired: Evident in oils that are many months old.

Hay, woody: Characteristic smell of some oils extracted from olives that have dried out.

Earthy: Characteristic flavour of soiled unwashed olives.

Fiscolo: Caused by the use of filtering panels which have not been perfectly cleaned; it reminds one of hemp.

Olearic Fly: Oil extracted from olives attacked by the olive fly: the flavour is both rotten and putrid at one the same time.

Impersonal: A serious defect for virgin oil as it means it does not have character or personality. It is a common trait of all manipulated oils.

Poor preservation: Even if not in direct contact, the oil absorbs the odours and flavours of everything surrounding it. It is a very common defect.

Dirty: This is said of oils that were in contact with the vegetable water for too long and have absorbed its unpleasant odours and flavours.

Phenic acid. Pertaining to poorly kept and very old oils.

POSITIVE ATTRIBUTES

Fruity: The oil is fruity when its flavour and aroma are similar to that of a mature olive. After pressing all oils seem fruity, but in most cases this characteristic disappears after a few months. Authentically fruity oils maintain this characteristic aroma through time.

Bitter: Characteristic taste of the oil produced by green olives.

Sharp: Tactile biting sensation. The typical flavour of fresh oils, usually accompanied by a brilliant green colour, which fades until disappearing with the passing of time.

Sweet: When the scent is graceful, gentle and not very accentuated. It initially gives a light sensation accompanied by an aftertaste of almond.

Aftertaste sensations considered to be positive

Harmonious: It is said of a complete oil with no predominant traces or flavours which are evident as soon as one tastes it. It is the best quality.

Characteristic: Particularly influenced by the area of cultivation or the specific orchard type. It is not necessarily a defect, and can often be a positive trait.

Aggressive: Disharmonious oil with one or more excessively intense components which overpower other components.

Artichoke: A flavour that reminds one of a pleasant, fresh raw artichoke.

Green: It is said of young, fresh, fruity and slightly herbaceous oil.

Soft: Made from very mature olives, pale gold colour. Very palatable aftertaste, leaning slightly towards sweet.

Rotund: It is said of oil with a pasty body that fills and satisfies although without outstanding aromatic characteristics. It is always extracted from mature olives.

Green leaf: A sensation obtained when small quantities of fresh olive leaves are added in the press.

Musky, nutty and woody: These are traces left by the oil, and while they may not be considered positive in the classic sense, they are frequently characteristic of oils belonging to a defined production area, which, when not overpowering, are very pleasing. 

< OLIVE OIL: MEDICINE AND HEALTH  [ Top ]

The nutritional properties of olive oil sistem from the unusual features of its composition. In ancient times olive oil was recommended as a hair preservative to maintain their natural colour; for the healing of stomach, liver and intestine ailments; to heal the skin from burns and to protect it from sunrays; it was considered indispensable for muscles and limbs massages. Although not denying the above properties in spite of their vagueness, current medical research recommends using olive oil in the diet in order to prevent ageing and preserve the body from cardiovascular and circulatory illnesses.

Indeed, clinical and therapeutic studies have demonstrated the particular relationship between saturated, monounsaturated and polyunsaturated acids characterising olive oil composition and the natural presence of micro components, such as tocopherols and polyphenols. These give it a series of precious properties such as an easy digestibility and resistance to cooking, a cellular ageing delay effect, a preventive effect against the formation of gaul stones, a favourable effect on cerebral growth, along with an antithrombotic and hypocholesterolemic effect.

Despite a disinformation campaign mainly based on a type of advertisement inappropriate for our times, the oil obtained from olive pressing absolutely remains the best type of fat to be found in the alimentary field.

After lengthy studies, in 1977 Professor Angel Keys of Minnesota University recognised the effectiveness of olive oil in the prevention of arteriosclerosis and heart attacks. Therefore he was the first person – in our times – to point out the value of the Mediterranean diet in which olive oil plays a primary role. Firstly, it is the only oil produced from the simple pressing of a fruit without any physical or chemical manipulation. Whereas, for example, vegetable oils are produced by extraction with the traumatic physical use of special equipment and chemical substances such as butane, propane and hexane.

Fats are needed by our body to help maintain an optimum temperature (estimated around 37°), but such fats should be neutral if not slightly acid. The three essential acids are oleic acid, linoleic acid and arachidonic acid. In the past it was felt that vegetable oils were superior to olive oils because of their greater linoleic acid content. Recent studies have found that the human body cannot assimilate more than 10-12% of the linoleic acid.

Moreover, olive oil is monounsaturated, while vegetable oils are richer in polyunsaturated fats. This is a fact essential to cooking and frying in oil, as, by bringing them to high temperatures, the unsaturated fatty acids become oxygenated and damage the body’s liver, kidneys, stomach and the cardiovascular apparatus. In short, olive oil tolerates higher temperatures before deteriorating. Furthermore, it does not increase the cholesterol level, but on the contrary, the olive acid diminishes the content of harmful LDL cholesterol, and preserves HDL cholesterol intact, which diminish the risk of arterial occlusion. And not only this, olive oil reduces gastric acidity and affects bile favourably and therefore diminishes the risk of calculi.

It even favours normal growth of bones in young people. Olive oil is therefore a very precious food, rich in chlorophyll, carotene, lecitine (natural anti-oxidant that stimulates the metabolism of fats, sugars and proteins), polyphenols (also anti-oxidants) and vitamins A and D. The various epidemiological researches carried out on the diets rich in extra virgin olive oil have demonstrated that for populations with a prevailing Mediterranean diet the level of myocardium heart attacks was remarkably lower than for populations with a prevailing continental diet. In addition, the stomach’s functionality is favoured by the oleic acid which also has beneficial effects also on pylorus motility.

The proportion of essential fatty acids in the extra virgin olive oil was found to be very similar to that found in breast milk, so this food can also be recommended for children’s diets. Furthermore, the balanced presence of monounsaturated and polyunsaturated fatty acids tends to favour a balanced presence in the brain’s structural lipids and optimal development of the skeleton.

In conclusion, the beneficial properties of extra virgin olive oil for the body are countless:

• It reduces LDL cholesterol levels

• It reduces risk of arterial occlusion 

• It reduces arterial blood pressure

• It reduces blood sugar levels

• It increases bile secretion

• It increases Vitamins A, D and E absorption

• It facilitates absorption of other vitamins

• It prevents arteriosclerosis

• It prevents myocardiac heart attacks

< QUALITY CERTIFICATION  [ Top ]

As with other agricultural products, oil quality certification has had a remarkable development during recent years. These days two different types of certification are possible: regulated and voluntary. The first is the regulated certification of a product in conformity with Community norms (Norm EEC 2081/92), used to obtain the Name of Protected Origin and the Indication of Protected Area.

 The Norm outlines the procedures required to obtain and manage this type of product certification.

The certification allows the single producer, or group of producers, to define the product’s certifiable characteristics, and certify them for their consumer’s benefit by using third party Agencies. It is indispensable in characterising and typifying the oil produced for the purpose of increasing the value of its peculiar features and favouring keen-eyed choices on the part of the consumer.

 The certification therefore represents a very useful evaluative instrument for oil helping to conquer new markets and to protect the consumer.