♦Quality and typicality
The olive oil is the most noble of vegetable fats and why is obtained from a fruit because it is extracted from olives by mechanical and physical that do not alter in any way the product, if applied correctly. It is also the only oil to be used immediately for human consumption without further manipulation unlike other vegetable oils that to be edible, must necessarily be corrected. While also recognizing a generic extra-virgin olive oil a level of quality significantly higher than seed oils, we can not assume that all products in that product category possess the same character value.
There are several chemical-physical and organoleptic parameters that differ significantly, and characterize the different olive oils, whose values are not the result of chance but the interaction of a number of factors that depend on both human choices, made in the whole production chain (human factors) that the climatic and soil conditions of the site of cultivation (natural factors).
Among the human factors within the agricultural practices and technologies and extraction techniques. The man worked on the entire production, helps to determine the degree of authenticity and product quality. An extra-virgin olive oil is defined as genuine when it was "obtained from the olive fruit only by mechanical or other physical means under conditions that do not lead to alterations in the oil, which has not undergone any treatment other than washing, decantation, centrifugation and filtration". From this category are "excluded oils obtained using solvents or using adjuvants having a chemical or biochemical or re-esterification processes and any mixture with oils of other kinds." Is also necessary that also possesses the physical-chemical and organoleptic parameters within the limits set by regulations in force. Then the authenticity can be defined as a kind of minimum quality that the product must have the time of consumption. An oil well as being genuine is the quality if some of these parameters are characterized by a numeric value is more favorable.
The concept of quality of oil tends, however, evolve over time, even to reflect changing consumer needs, always looking for products that meet new standards of quality and typicality. The compositional characteristics of oil obtained from olives depend on certain factors concerning the choices agricultural and technological processes of extraction. The first type of factors may be related to the type of cultivar used, the agronomic practices adopted and the degree of ripeness of the olives. The cultivar influence both the fatty acid composition that the phenolic content, although the first component is more influenced by environmental conditions, while the latter is more dependent on the germplasm used. Play, then surely an important role and how the time of the olive harvest. There is another element that characterizes the intrinsic qualities of an extra-virgin olive oil: the typicality.
Is considered a typical food product that has organoleptic characteristics (and other) special, which are readily identifiable and that makes it unique and recognizable by others in the same category.
♦The organoleptic characteristics of extra virgin olive oil
In addition to the invaluable nutritional and health benefits also peculiar organoleptic characteristics of virgin olive oil play an important role in directing consumers towards the use of that product than to other types of vegetable oils. Anyone who has entered into an olive oil press during the campaign will remember with pleasure the intense scent of fruity olive oil that permeates the room and can be affected by sniffing a good virgin olive oil, this distinctive scent is one of positive attributes, though the main, which constitute the aroma, or all volatile components from the oil that kept coming to stimulate cells of the olfactory epithelium.
The virgin olive oil has an intense aroma because it is able to release small molecules, with very low levels of olfactory threshold. Currently, through sophisticated instrumental techniques, we have identified more than 180 different molecules that may contribute to the aroma profile of virgin olive oil. The volatile fraction of virgin olive oil obtained from healthy fruit, harvested at the right stage of ripeness, stored in a manner appropriate pending the processing and then processed, consists of about 80% compounds with six carbon atoms (C6 ) that are produced by enzymatic oxidation through a kind of biochemical cascade known as the lipoxygenase route. All of these volatile molecules and the relationship between their quantities are essential for the formation of these secondary olfactory sensations can characterize the different types of oil, vegetable notes such as grass and leaf vegetables such as tomatoes and artichoke or fruits like apples, bananas or almonds.
This enzymatic process kicks off during the milling-pressing, where is the breakdown of cell structures and continues with release of enzymes during mixing due to prolonged contact between the oil phase and aqueous phase rich in enzymes. The volatile compounds that are formed gradually during these operations are incorporated in the oil and determine the flavor profile. The type of cultivar, soil and climatic conditions and degree of ripeness of the olives, as well as different stages of technological process of production of oil and the conditions adopted during storage, are all factors that can profoundly affect both the formation of positive character, that the formation of defects detected using negative hints of oil.
If many are perceptible scents smell, taste those determined to have only four: sweet, bitter, salty and sour and are due to the presence of specific substances in food that can dissolve in saliva and bind to specific receptors on the scattered language and oral cavity. The virgin olive oil is characterized by only a hint of bitter taste, as it has no sugar in its chemical composition can determine neither sweet, nor salts or acids that can be perceived. What the average consumer often referred to as "acid" is really the spicy sensation that originates from inflamed nerve endings that innervate the tongue due to the presence of certain molecules in the oil.
To sum up then from the standpoint of taste virgin olive oil is characterized by bitter and spicy, more or less intense due to the presence of small quantities of valuable antioxidants called "polyphenols and phenols. The quantity of these compounds is related to many variables both agronomic and technological.
♦ Tasting techniques
Regarding the technical tasting of extra virgin olive oil, it should be noted that, like all other food is eaten alone, sipping a small amount corresponding to the contents of a tablespoon. The glass within which is the oil is dark (amber or cobalt blue) that would prevent to detect the color of the product inside, to avoid unnecessary constraints as the color of the oil is not a quality parameter.
Before the smell is appropriate to heat the oil at a temperature of 28°C to promote the volatilization of aromatics, keeping the glass tasting ended with the suitable glass lid. The evaluation phase so-called olfactory direct or external, consists of some brief but intense breaths just above the glass through which to evaluate the intensity of fruity olive oil, possibly distinguishing whether the fruity olive recalls more fresh, then defining a fruity olive green or more mature, or ripe fruit and can also assess whether the type and intensity of other smells good.
It then passes the examination Taste: to appreciate the various nuances of taste, it spins the oil in your mouth for ten seconds then be vaporized oil in the mouth without swallowing, inhaling air from the lips slightly parted with tongue rests against the palate. This transaction, which in slang is called stripping, can be repeated several times. Thanks to the temperature of the oral cavity, there is a release of volatile molecules contained a fragrance oil which, through the nasal route, arriving at the olfactory membrane, this indirect path promotes olfactory assessment since the speed of transit of volatile molecules is slower directly compared to inhalation.
In general, it is notable that the retro-olfactory assessment generates the perception of aromas, odors perceived with respect to the direct smell, are more complex and articulated. The analysis is limited to the assessment of gustatory attributes of bitter and spicy. Any sweet sensation that characterizes some oils is due more than anything else the lack of bitterness and the tactile sense of fluidity due to fatty substances.
Extremely important when you run the sensory analysis of extra virgin olive oil, is the ability to detect the presence of defects, to achieve this result, the assessor needs of the long path of training required by current regulations .
The main defects that a tester must be able to recognize are: Winey or vinegary, feeling that recalls the smell of vinegar or wine, due to the formation of acetic acid, ethanol and ethyl acetate after acetic fermentation (yeast and acetic acid bacteria) on any of the sugars of drupa. This defect arises especially when working olives poor quality as overripe and damaged or have stayed too long awaiting processing especially if not in optimum conditions.
The heat, smell unpleasant and characteristic product from degradation by microorganisms of the genera Clostridium and Pseudomonas formation of compounds with four and five carbon atoms branched. It 's another defect caused mainly by incorrect storage conditions of olives waiting to be submitted to the extraction process. In traditional systems for pressure, because the gap processing, pulp and waste water plants stop for variable times on straining; under these conditions can easily take initiation reactions of fermentation of sugars and amino acid degradation, producing compounds birds responsible for the aforementioned defects Winey and reheating.
The mold smell that recalls the smell of damp cellar, due to mold Penicillium genera Aspergilus and olives on damaged or incorrectly stored before processing and attributed to the formation of volatile compounds to 8 carbon atoms.
The sludge, extremely unpleasant odor caused by reactions butter anaerobic fermentation against waste water vegetation and organic sediments that remain in the oil if, once produced, is not filtered or decanted properly.
The rancid smell bad due to oxidation of the oil when not being kept in a suitable way, or away from light, heat sources and without contact with air.
♦ Classification of oils
Starting from 2002/2003 came into force the new CEE regulations (Reg 1513/2001 Art. 1 and Annex, Reg 1019/2002) which classifies the oils extracted from olives and it regulates the marketing and labeling. Was first reduced the number of categories on the market and, more importantly, was lowered to 0.8 g oleic acid on the free parameter in 100 g of olive oil.
The fact remains that the oils extracted from olives with a free acidity expressed as oleic acid are defined above 2g/100g obvious and must be rectified, the categories in retail trade in oils are:
Restando il fatto che gli olii estratti dalle olive con acidità libera espressa in acido oleico superiore a 2g/100g sono definiti lampanti e devono essere sottoposti a rettificazione, le categorie in commercio degli olii al minuto sono:
• Extra virgin olive oil, free acidity expressed as oleic acid than 0.8 g/100g and other characteristics correspond to those laid down for this category, aroma and taste that is almost perfect;
• Virgin olive oil, free acidity expressed as oleic acid at most 2g/100g, and other characteristics correspond to those laid down for this category;
• Olive oil, mixture of refined olive oil with virgin olive oil, free acidity expressed as oleic acid at most 1g/100g and other characteristics correspond to those laid down for this category.