29 Oct Which is the extra virgin olive oil?
The conversation, of course, always happens for the characterized as “extra virgin olive oil”, which is sold well abroad. To get such labels, however, an olive oil should be as it comes out of the mill, without treatment and with an acidity of less than 0.8%. If the acidity is more than 0.8% but does not exceed 2% then it is simply characterized as “virgin” and more than 2% has the designation “industrial”, replacing the older “lambande”, “coupe” and in the last stage the “refine”.
To be characterized as unheated an oil must have come out of the mill without its temperature exceeding 28 degrees Celsius. In several mills they rise the temperature even to 60 degrees so as to slightly increase the production, at the expense of quality. Because polyphenols above 28 degrees become more water soluble and leave with the wastewater of the mill. Especially when some people leave the pulp of olive oil in the grinder for one and a half hours at 40 or 50 degrees Celsius. Another negative issue for the consumer is the expiration date in a bottle. Because unfortunately it is allowed to extend up to 18 months after bottling (!) and not 18 months from production. So you can bottle 2010 production in 2011 with expiry in 2012! We only have to look at the packaging and to have as much time as possible to expiry. It should also be stated at least that this is a “Greek product” and not to have the highly suspicious indication of “Greek construction”.
Acidity and oxidation
Oxidation, which was formerly called draining is a chemical lesion and happens when the olive oil comes in prolonged contact with light and oxygen, so it gets an unpleasant taste, something like dirt. The degree of free acidity, as is the exact, is defined as the amount of free fatty acids in olive oil and is expressed as a percentage (%) of oleic acid. Oxidation and acidity are two different concepts.
Do not confuse them.
One of the basic things you learn when dealing seriously with the subject of “olive oil” is that the green olive oil should not be considered a luxury, a separate class of oil, but something that is self-evident. For good quality oil, the olive must be harvested when it is still hard, half-green to half- purple. In all exhibitions and international tastings such olive oils are mainly awarded. It is the olive oil that has bitterness, strong aroma and makes you cough when it has passed from the mouth to the throat. And they examine three features that are coded in just three words: BEAUTIFUL – FRUIT – SPICY with a score of 1 to 10 for each (in some tastings they even use blue glasses so as not to be affected by color). And we should eat green olive oil because then the so useful polyphenols are present in the maximum amount. When the olives are unripe. And these substances are just under their skin. High content of polyphenols in an oil also means greater resistance to oxidative stress from air, light and temperature. An important element for the maintenance of an olive oil. A good olive oil should contain about 200-250 mgr / kgr while 250-350 mgr / kgr is considered to be excellent performance. The most basic varieties that give olive oil here in Greece are Koroneiki (more or less everywhere), Chalkidiki, Amphissis (mainly in Central Greece), Maroneia (in Eastern Thrace), Kolovi and Adramytini (in Mytilene) and and the well-known Manaki in Peloponnese. Some Athinolia and also in Attica several olives from Megara.
Olive mills of destruction
However, where our interlocutor is overwhelmed and becomes denunciatory about it is the issue of olive mills. First of all, he considers that what still exists in Greece is completely wrong, the oil mills are paid in kind, that is, to hold a part of the oil that your olives make. Because so they press continuously for a larger quantity, thus dropping quality with the highest temperatures, with the most water and by encouraging producers to gather olives when they are more mature. Also, when Italian buyers appear with cash they buy what they want, as low as they want.
“You may have very good quality olives and the olive mill destroy your olive oil,” he tells me. At an oil mill that went along with foreign stakeholders, there were no cups to taste the oil, and people asked him: “But, here they are not trying the oil they are producing? ” He also mentions something that an Italian chief designer for oiling machine said to him a few days ago: “You Greeks hardly change.” Today in countries like Italy, the equipment of the olive mills has reached levels that many have not even imagined. Tanks where over the oil is now supplied nitrogen gas to avoid contact with the oxygen of the air that oxidizes the product, different production lines for olives with different degrees of maturity so as the oils of the more mature not to get involved with the most unripe, the oiling should be done within 24 hours of arrival at the mill and the olive not to wait pressed for days in sacks stacked on top of one another (which now should not be used and replaced with plastic crates). Picking the pulp should not last longer than 40 minutes and the olives should be picked up before December comes in.
What determines the price
The stock market of olive oil
Peroxides have to do with the oxidation state of olive oil. The so-called “peroxide value” determines the concentration of peroxides in the sample. Peroxides are major oxidation compounds, which occur during the processing and storage of the olive oil as a consequence of the presence of oxygen. In a second step of the oxidation process, peroxides are broken down into different final oxidation products. To classify an olive oil as an extra virgin the maximum peroxide value must not exceed 20 milliequivalents of oxygen per kilo of olive oil.
Another indicator useful for determining the quality of olive oil is absorption in the ultraviolet spectrum. This measurement gives information on the quality of olive oil and, in particular, to determine the degree of its oxidative deterioration. The measurement is made at two wavelengths, 232 and 270 nm. At the first wavelength they absorb the primary oxidation products (conjugated peroxides), while in the second the secondary oxidation products (aldehydes, ketones). The difference of the absorption gives information about the oxidation state of the olive oil. The lower the price, the higher the quality of the olive oil and should not exceed 0.01 for “extra virgin olive oil”. Other qualitative markers are K232 that should not be over 2.5 and K270 should be less than 0.22. From their prices can be perceived if there are many oxidizing substances and if it has become adulteration.
A very good olive oil must, according to Mr Frantzola, meet at least 4 of the following 6 criteria: 1. Acidity <0.3, 2. Number of Peroxides <8, 3. Polyphenols> 200 mgr / Kgr, 4. On the scale of tasting to take for Fruity> 3.0, For Spicy> 2.0, 6. For Bitter> 2.0.
If given in percentages the factors that shape the quality will be: 60% the mill, 20% the degree of ripening, 15% the variety, the various diseases, especially the fly, 5% the local conditions.
What we need to know
The decalogue of the consumer
1. Acidity is different from oxidation. The price of acidity has to do with the condition of the fruit and how it is moved until it reaches the mill. Oxidation by how much oxygen comes into contact with the product after the fruit has been pulped and transformed into an olive oil.
2. Olive oils which will not be entitled ‘extra virgin’ or even ‘virgin’ due to some serious defects, they are picked up by some industries that lower acidity by using chemical and the odor by using filters. They raise the temperature to 220 degrees and produce a neutral product. Mix it with 5% -10% extra virgin olive oil and on the packaging write this first, although it is in a much smaller quantity.
3. Fry as much as possible with olive oil and not with seed oils (used in foreign cuisines because there was no olive oil), as various chefs propagate, preserved in transparent containers and often adulterated.
4. A good quality olive oil can withstand frying up to five times according to Mr. Frantzola. He does not even want to hear about the various seed oils, which, he says, do not have any antioxidants like polyphenols, and they alter as soon as they warm up.
5. He also does not propose to cook with olive pomace oil but prefers it in any case from seed oils.
6. We must be cautious about the oils available in transparent packaging, no matter how well designed they are. As Mr Frantzola observes: “Chlorophyll in the light acts oxidisingly for olive oil and in a short time oxidizes it. And we want to buy oil, not cologne. ”
7. The old millstones, which are cleaned more difficult and rarely, do not give better oil than we can get in modern mills. The olive oil that is extracted in modern three- or two-stage mills is bitter than that of stone mills and we prefer it precisely for this reason. Also, long-term kneading and high temperatures reduce bitterness because hot water increases the solubility of glycosides. The two-phase centrifugal system is preferable because it produces olive oils with a stronger bitter taste since in the three-phase process we also have water in the process. And we want as much bitterness and burning as possible in the neck.
8. The oiling should start around 20-25 October and not even after November, because the prevailing view is that the longer the olives mature, the higher their oil yield will be. In Italy most producers start from mid October or even from 1st October.
9. As long as the oil stays loses its beneficial ingredients, as demonstrated by a study done four years ago: for example at 22.10, polyphenols were 440 mgr / Kgr and within 40 days, at 3.12, they had fallen to 209 mgr / Kgr.
10. There are even very good “extra virgin” olive oil on the shelf of the grocery store, while the foreign ones are sold at prices that at this time seem fairly unbearable.
Scoring an oil
There are many items that you can search in the oil. We are confined to the three most important: the fruity, depending on the variety of olives and is felt directly from the nose or the backbone, the bitter, that has to do with how unripe the olives were, and the spicy, characteristic of the oil produced at the beginning of the olive oil period. The latter is caused by the action of phenolic substances, spreads over the entire oral cavity and is eliminated a few seconds after the test. The intensity of the spicy is reduced during the maturation of the olive oil. The skilled can understand if the olives stayed for a long time in the sacks, if they fermented, if they stayed longer than they had to in the kneading, if the oil was heated above 28 degrees if it came from dried olives, if salt was used or if it came into contact with water. There is in the Internet a study of TEI of Crete – School of Technology-Agriculture (head D. Lydakis) for the color, flavor and aroma of the oil with many elements worth considering.
The first is the color. “It is one of the most important organoleptic characteristics, since it is associated with other qualitative aspects of olive oil ‘ reported in this study. The color is determined mainly by chlorophylls (green) and carotenes (yellow-red). Genetic factors, way of production and degree of maturity play their role and as long as the oil stays, the color is altered. However, testers do not focus their attention very much on color. They move on to taste and aroma.
For flavor it says: “The five basic flavors are sweet, salty, sour, bitter and umami. The virgin olive oil does not contain sugars or salt and the sense of sour, due to free fatty acids, is not perceived because they are not soluble at the temperature of the human body. The bitter in virgin olive oil is due to the compounds present in the fruit of the olives, glucosides. They include substances such as tyrosol and hydroxytyrosol, responsible for bitter taste. ”
The olive oil extracted with the metal cylinders is bitter than that of the millstone. Long-time kneading and high temperatures reduce bitterness, but this is not considered a qualification for our oil. Also, pressure extraction and two-phase centrifugal system give olive oil with more intense bitterness. Glucosides are the substances responsible for the astringent taste of some virgin olive oils. Their presence creates a sense of dryness and unripe in the mouth, a sour that reminisces of wines or quinces and a burning sensation. Finally, in terms of aroma, for olive oil is considered to be produced from volatile compounds of low molecular weight. The stimulus can be immediately sensed when the fragrance reaches the nasal epithelium through the nose, and indirectly, when the perfume, which becomes volatile at body temperature, passes through the mouth in the olfactory epithelium.
Over one hundred volatile compounds have been identified in virgin olive oil that contribute to its distinct aroma, including C6 alcohols, aldehydes and esters. None of these compounds alone can explain the overall sense of aroma.
According to the study of TEI of Crete: “The stage of ripening fruit at harvest affects the aroma of olive oil. The maximum perfume intensity corresponds to the maximum content of volatile substances at the optimum stage of maturation. ” Just as with the taste, the olive oil extraction system and the processing conditions – especially during the grinding and kneading of the wrist – affect the type and intensity of the fragrance. Strong milling and prolonged kneading at high temperatures have a negative effect. The pressure or two-phase centrifugal system produces olive oils with a stronger aroma. According to the results of our tests, the most expensive was not the best, a cheap oil you find on the supermarket shelf in your neighborhood was not that bad, an Italian was brilliantly intense and the world-renowned champion defended its reputation.