Olive Oil Categories

QUALITY CHARACTERISTICS

The quality of olive oil is determined by a series of chemical, physical and organoleptic characteristics.

Chemical Characteristics

  • The acidity is a factor of deterioration caused by microbial and enzyme activities in the presence of moisture. It grows mainly due within the fruit when it is infected by Bactrocera oleae or when it is stored prior to processing at elevated temperature and bad ventilation conditions. The acidity is measured by the free fatty acid content expressed as oleic acid (g./100g or %.).
  • Oxidation gives the oil defective taste caused by contact with oxygen, light, metal (iron, copper) and high temperatures. It is therefore recommended to maintain the olive oil in closed and opaque encolosures, at low temperatures. Olive oil packaged in glass or plastic bottles should not be left for days exposed on the shelves of Super Markets, house kitchens or restaurants tables. Oxidation is estimated with the "peroxide" that for virgin olive oil should be below 20 meq O2 / kg, or by determining the constant K in the ultraviolet spectrum spectrophotometer. 

Natural characteristics

  • They comprise color, viscosity, etc. The olive oil color ranges from greenish yellow to golden yellow, and depends mainly on the state of maturity and the fruit color during processing. At the beginning of the harvest period, the olive oil is usually green because of chlorophyll from green fruit or olive tree leaves when there are in a significant proportion compared to the fruit. Chlorophyll exposed to light favors the oxidation of olive oil while its absense inhibits it. 

Organoleptic characteristics

  • They mainly include the taste and aroma and olive oil odor, which are evaluated by tasters under a specific procedure laid down by the International Olive Council. During Organoleptic evaluation (Lazaraki, 2003) positive and negative qualities are assessed. 

 

Positive properties are mainly fruity, bitter and spicy.

  • The Fruity flavor is a combination of odours and flavors from healthy, fresh olives ripe or unripe. The Fruity flavor is perceived either by the nose , and depends on the variety of olives. The Fruity is the most important property of the Organoleptic  evaluation and if it is not present the olive oil can not be classified as "excellent or virgin." The Fruity flavor is highly appreciated and is a key element of evaluation in quality competitions and it is distinguished in bright, medium and light.
  • The spicy is the sense of "spicy" in the throat which is a characteristic of oilve oil extracted mainly from unripe olives called "green olive oil". It is also due to the action of phenates substances on the edge of the trigeminal nerve. This sensation goes away seconds after tasting.
  • The bitter taste is a characteristic derived from fruits green or greenish and depending on the intensity can be more or less pleasant. In no case, however, is not considered a defect.
  • The negative properties are mainly atrochado (which occurs mainly in Spanish olive oil), the mold, the dregs, the wine sauce, metallic, tango, burnt, straw-wood, thick, lubricants, waste water, the brine, the broom, the Earthy, worm, cucumber etc. Whereas the olive oil in Crete negative attributes never appear. The reference is to the methodologies of the International Olive Oil Council and is derived from olive oil from other areas. 

 

OLIVE OIL CATEGORIES

  • Extra virgin olive oil​

Oils obtained from olives solely by mechanical or other physical means particularly under thermal conditions, that do not lead to deterioration of the oil, and which have not undergone any treatment other than washing. The free acidity, expressed as oleic acid, is at most 0.8%. Also K270 should be less than 0.18 and K232 should be less than 2.25.

  • Virgin olive oil​

Oils obtained from olives solely by mechanical or other physical means particularly under thermal conditions, that do not lead to deterioration of the oil, and which have not undergone any treatment other than washing.  The free acidity, expressed as oleic acid, is at most 2%. Also K270 shoulb be less than 0.25 and K232 should be less than 3.5. For this type of olive oil the term "Fine" is regularly used.

 

  • Degraded (Inferior) Olive oil​

This is a virgin olive oil whose free acidity, expressed as oleic acid, is more than 2% (2gr in 100gr).

 

  • Refined Olive Oil​

Οlive oil which has undergone a refining process (due to poor quality).

Αcidity (%) is defined in grams of free oleic acid contained in 100g of oil. As K270 and K232 are defined in light absorptions at 270nm and 232nm respectively, a sample of one gram of olive oil dissolved in 100ml isooctane and placed in a quartz cuvette 1cm thick.

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