To be classified as natural olive oil, it must be extracted from olive fruit solely by mechanical processes of milling, pressing and separation and must meet some basic tests to ascertain that there has been no alteration in the nature of the oil.
Extra Virgin Olive Oil is the highest quality oil amongst natural olive oils. It has the lowest levels of free fatty acids and excellent aroma and taste. Virgin Olive Oil is the second grade after Extra Virgin Olive Oil and it shows slightly higher free fatty acid levels and average aroma and taste. When natural oils are unfit for human consumption due to their poor chemical and/or organoleptic characteristics, they receive the denomination of Lampante and they need to be refined prior to their use.
Refined oils are subjected to chemical processes such as gum extraction (the application of mineral acids to aid in the removal of acidity from the oil), neutralisation (the addition of a strong alkali such as caustic soda to remove excess free fatty acids), decolourisation (filtering the oil and using clay or activated carbon to lighten the oil colour), deodorization (treating the oil with superheated steam under a vacuum to remove off-smells), etc. When this refined oil is blended with virgin oil, we obtain what it is classified by the Australian Standard as “Olive Oil, a blend of refined and virgin olive oils”.
While the Australian Standard and other international standards have a number of areas in common, particularly associated to worldwide recognized analytical methodologies and critical limits, AS 5264-2011 significantly differ in a number of aspects. One of those points of difference is the use of simpler and clearer commercial denomination of the different categories of olive oils in order to avoid misleading and confusing terms such as extra light olive oil or pure olive oil.
Both extra light olive oil and pure olive oil are blends of a large proportion of refined olive oil and a small portion of virgin or extra virgin olive oil. Typically, extra light olive oil will contain more than 90% refined olive oils. As they are refined, they are “lighter” in aroma and flavour but not calories when compared with other olive oils.
Extra virgin olive oils are the healthiest choice as the non-chemical and non-high temperature extraction process employed in their production retains the natural antioxidants, vitamin E and phytosterols present in the olives. These substances have been implicated in reducing coronary disease and lowering cholesterol levels. All olive oils contain high levels of monounsaturated fats, which as well as being ‘healthy’ fats, are also more resistant to oxidation, so they last longer in storage, and can be reheated more often than many other cooking oils with a larger fraction of polyunsaturated fats.