Curiosità sull’olio extra vergine di oliva
L’olio extra vergine di oliva è il prodotto ottenuto dalla estratto a freddo del frutto delle olive mediante processi puramente meccanici e tale caratteristica lo rende un vero e proprio alimento, naturale e con un profilo aromatico e gustativo unico.
La misura della qualità
Un olio extra vergine di oliva, per essere classificato come tale, deve rispondere ai parametri di qualità imposti dal Regolamento (CE) 796/2002.
Questa valutazione di qualità si basa sia su risultati di analisi chimiche che hanno lo scopo di accertare la qualità delle olive impiegate(acidità) e lo stato di conservazione del prodotto(perossidi, assorbimenti spettrofotometrici nell’ultravioletto) che su risultati di analisi sensoriali.
- acidità libera (inferiore a 0,8%) che dipende dalla qualità delle materia prima e non si percepisce all’assaggio;
- numero di perossidi ( minori di 20 meq O2/kg) che misura l’ossidazione primaria dell’olio;
- indici spettrofotometrici K232 e K270 rispettivamente inferiori a 2,5, 0,22 che forniscono informazioni sullo stato ossidativo del prodotto e quindi sul suo grado di invecchiamento;
- analisi sensoriale (mediana del fruttato > 0 e mediana dei difetti = 0) che attesta l’assenza di difetti nel profilo aromatico dovuti eventualmente a condizioni non ottimali dell’intero processo produttivo.
La qualità chimica e sensoriale di un olio extra vergine di oliva è quindi il risultato dell’interazione di quattro fattori fondamentali:
- la qualità delle olive impiegate;
- la qualità del processo di trasformazione;
- le modalità e i tempi di conservazione;
- la tipologia di imballi utilizzati.
As for the raw material, it is necessary for the olives to be healthy and harvested at the right stage of ripeness by forced detachment from the tree, after the harvest, olives are taken to the mill for immediate processing.
Starting from a good raw material, the numerous technological innovations of the transformation process allow today to obtain an extra virgin olive oil of superior quality compared to the past and allow to modulate its sensory characteristics according to the needs of the consumers.
Proper conservation is fundamental for the quality of the extra virgin olive oil, if not accurately executed, in fact it can compromise all the efforts made to obtain a high-quality oil during the production and processing phases. During conservation, the oil tends to oxidize, it is therefore necessary to control the natural phenomenon of oxidation to ensure that the consumer get a flawless product.
The measure of genuineness
Unfortunately, today quality analysis is not enough to guarantee the authenticity of the product that arrives on our tables. A check of the genuineness has therefore become important to verify that the product is not subjected to technologies other than those traditionally used, nor added substance unrelated to its nature.
Coop Italia in 2009 commissioned the University of Bologna to verify the authenticity of the oils on the shelves. Here the link to the article on the website teatronaturale.it. Synthesizing the result on 24 samples, 10 were strongly suspected of deodorization, 10 were genuine and 4 with doubts (alkyl esters between 40 and 70).
The technique of tasting
General rules for the correct execution of the tasting tests:
- preferably in the early morning hours;
- refrain from smoking at least 30 minutes before the tasting;
- do not use perfumes or soaps with strong smells;
- do not eat anything in the previous hour;
- distance one sample from the other by at least 15 minutes;
- after each tasting rinse mouth with sparkling water;
It begins with the olfactory evaluation of the oil. For this phase the glass is brought to a temperature of 28 º C allowing the oil to volatilize. Bring the glass to the nose and inhale slowly and deeply 2 or 3 times in a row, focusing on the perceived sensations.
Then we pass to the gustatory evaluation by taking a small sip of oil and distributing it over the entire tongue and mouth cavity. In this way the gustatory and aromatic perceptions are evaluated also the percussions of the spice, astringent etc…
With short and successive aspirations air is introduced to the mouth favoring the retronasal perception of its volatile aromatic compounds.
At this point an evaluation can be made, positive or negative, by synthesizing the olfactory and gustative sensations proved during the phases of the tasting. The link to the profile sheet to be used by the taster. The Benefits and Defects of extra virgin olive oil..
Guidelines for the Conservation of Extra Virgin Olive Oil
An old proverb says, “Old wine, fresh oil”. Unlike wine, in fact, in the process of aging oil loses many of its best qualities.
Producing a high-quality extra virgin olive oil is also not enough to guarantee quality to the final consumer unless a series of measures are taken to maintain it over time.
As well known, extra virgin olive oil, once obtained, undergoes a natural process of qualitative decay due mainly to the establishment of oxidative phenomena that tend over time to affect its quality. The speed with which this happens such decay can be considered tolerable, depends on many factors, some of which are difficult to control, but others under the potential control of operators and final consumers.
The regulations quote that it should preferably be consumed within 18 months of its packaging. In fact, the method of preservation deeply affects the shelf life of the product.
Here are some valuable tips for conservation:
- Always use clean and well-sealed small containers.
- Limit the contact between oil and oxygen as much as possible.
- Store at a temperature between 12 and 20 degrees.
- Store in dark or in non-transparent containers.
- If stored in storage tanks we recommend the adoption of containers with conical bottom for the simple elimination of sludge (water, solid sediments, impurities in general). It is also advisable to use airtight tanks and the full load of the storage tank to discharge the oxidative effect.
Stainless steel tanks have the optimal characteristics for oil storage, in fact they protect from light, are inert, easily washable and available in very different formats to meet every need.