Introduction

This article describes the official grades of olive oil, based on the Australian Standard for Olive oils and olive-pomace oils.1 Similar to international standards, this standard includes both laboratory analysis and sensory testing to define the grade of an olive oil.  However, it is more specific and includes two additional chemical tests to determine the freshness, quality and authenticity of an olive oil.2

Free fatty acids (FFAs) of “free acidity” is a simple and common test used in olive oil standards that is indicative of good harvesting and handling processes. Their presence in an oil indicates that degradation has occurred in the oil due to poor handling during processing.3 This can include numerous factors such as poor-quality or bruised olives used to produce the oil and delayed or inadequate harvesting and storage techniques prior to crushing.4,5

FFAs can also influence the organoleptic properties of the oil. Sensory defects, including negative flavour and odour attributes are the second type of testing used to formally grade an oil via a panel of olive oil testers trained to detect the presence of defects.  Defects are the result of factors such as poor handling during processing and microbial spoilage of the olives prior to processing.1

 

 

Naturally Obtained Olive Oil

Naturally obtained olive oils are obtained solely by mechanical or other physical means including first cold-pressing, under conditions, including thermal conditions, that do not lead to alterations in the oil. It is important to note that cold-pressed refers to a method used to extract the oil. Not all first-cold pressed oils pass the quality parameters to be classed as Extra Virgin Olive Oil (EVOO), and lower grades can also be first-cold pressed.

Extra Virgin Olive Oil (EVOO) is the highest grade of Olive oil. It is a natural olive oil that has a free acidity, expressed as free oleic acid, of no more than 0.8 grams per 100 grams, and no sensory defects. As a result of its high quality and minimal processing, EVOO is high in natural antioxidants, Vitamin E and phytosterols from the olive fruit and free of artificial trans fats that can be produced during refining.6

Virgin Olive Oil (VOO) is also naturally obtained by the same process as EVOO. However, it is a lower quality oil, with a free acidity of no more than 2.0g per 100g and a median of sensory defects equal or less than 2.5. VOO is moderately high in natural antioxidants and is considered less healthy than EVOO.

Lampante Olive Oil is also a naturally obtained oil, however, it’s quality parameters render it unfit for human consumption without further processing. It has a free acidity level of more than 2.0g per 100g and/or a median of sensory defects higher than 2.5.

 

 

Refined Olive Oils 

Refined olive oils are not obtained by natural means. Though obtained from natural oils, they have passed through a refinery and undergone further processing such as deodorization.

Refind Olive Oil is obtained from natural olive oils but is further refined by methods including deodorization which do not lead to alterations in the initial glyceride structure. It has a free acidity of no more than 0.3g per 100 grams. This low acidity content is due to the refining process rather than quality production.  The refining also strips the oil of any natural antioxidants found in unrefined oils and produces artificial trans fats.

Olive Oil is a blend of refined olive oil and natural olive oils (~ 5 – 10% of EVOO or VOO) fit for human consumption. It has a free acidity of not more than 1.0 grams per 100 grams and a median defects equal or less than 2.5.

 

 

Olive-Pomace Oils 

Olive-Pomace oils are the oils obtained by treating the olive pomace with solvents or other physical treatments. It includes crude olive-pomace oil, Refined Olive-Pomace Oil and Olive-Pomace Oil which is composed of Refined Olive-Pomace Oils and Virgin or Extra Virgin Olive Oils.

 

 

Conclusion 

The two main olive oils present on supermarket shelves in Australia are either Extra Virgin Olive Oil or Olive Oil. Whilst these two oils have the same fat profile, due to the production methods and quality of the olive fruit used, they are very different in terms of taste, quality and health attributes. As a result, Olive Oil is stripped of the high level of natural antioxidants found in EVOO and is also high in trans fats that are produced from the refining method.

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