Free Fatty Acid (FFA): For an olive oil to be graded as Extra Virgin it must have a maximum FFA limit of .8% (.8g per 100g) according to International Olive Council (IOC) quality standards. FFA is indicative of the quality of the olives used to produce an oil. A low FFA value indicates that the olives were picked and processed immediately. A high FFA value indicates that the olives were damaged, overripe, infested by insects, overheated during oil production or simply sat too long before being processed. While a low FFA does not always guarantee high quality oil in and of itself, a high FFA almost always indicates poor quality oil.
Oleic Acid: Oleic Acid is a monounsaturated omega-9 fatty acid found in olive oil and is one of the main components that sets olive oil apart from other types of vegetable oil. Oleic Acid helps to lower blood pressure and cholesterol; thus, it is considered the good fat in olive oil and recommended as a substitute to saturated animal fat. To be graded as Extra Virgin the percentage of Oleic Acid in relation to overall FFA must be greater than or equal to 55% according to IOC standards.
Peroxide Value: An oil’s Peroxide Value indicates the extent to which an oil has been oxidized. When Free Fatty Acids in an oil react with oxygen, peroxides form that cause fat to turn rancid, so in essence the Peroxide Value is the measure of an oil’s rancidity. A high Peroxide Value is an indication that the olives were exposed to extremely high levels of heat, light or oxygen at the time of production. It can also indicate poor processing practices, substandard olive condition, use of old olives, improper storage of olives or a combination of these negatives. For an oil to be graded Extra Virgin it must have a maximum Peroxide Value of 20 (miliequivalents per kilogram) according to IOC standards.
Polyphenol Content: Polyphenols are powerful anti-inflammatory antioxidants found in many foods, but they are generally found in very high concentration in EVOO. Polyphenols are cited to be responsible for the low incidence of heart disease and Alzheimer’s associated with the Mediterranean diet; therefore, the higher an oil’s Polyphenol Content, the healthier the oil is. Polyphenols impart flavor characteristics of bitterness and pungency as well, so an oil with a strong pepper finish or intense bitterness often signifies a higher Polyphenol Content. Currently there is no established international standard for minimum Polyphenol Content in EVOO.
DAGs: The DAG test is a freshness test that measures the ratio of 1,2-diacylglycerols to the total diacylglycerols in an oil. In fresh olive oil made from high quality olives, the prevalent DAG is the 1,2 form. As an oil ages the DAG in the 2 position migrates to the 3 position resulting in a higher concentration of 1,3 diacylglycerols. Hot storage temperatures, higher FFA levels and refining an oil can also speed up this migration. Having a high ratio of 1,2 DAGs to the total DAGs is not only an excellent indicator of freshness but also an indicator of sound production techniques, high quality olives and a lack of refining. Currently only the Australian Olive Association (AOA) requires a DAG value greater than or equal to 35% for an oil to be graded Extra Virgin.
PPP: The PPP test is a freshness test that measures the degradation products of chlorophyll in olive oil. As an oil ages, chlorophyll pigments break down into pheophytins and then into pyropheophtins. The rate at which this degradation occurs is steady and can be measured, so a low percentage of pyropheophytins to total pheophytins is a good indicator of an oil’s age/freshness. The degradation of chlorophyll can also be sped up by exposing an oil to high temperatures, so a low PPP score is also a good indicator that no refined or deodorized oil is present. Currently the AOA requires a PPP value less than or equal to 17% for an oil to be graded Extra Virgin.
UV Absorption: UV Absorption serves as a secondary test for rancidity in olive oil. Elevated UV levels indicate oxidized, poor quality oil that has possibly been refined or adulterated. For an oil to be graded Exta Virgin, IOC standards mandate than an oil’s K232 value must be lower than 2.5%, its K270 value must be lower than 2.2% and its DeltaK value lower than .01%.
Taste Analysis: According to IOC standards, an oil must also pass a taste analysis performed by an internationally accredited tasting panel before it can be graded as Extra Virgin. The tasting panel must judge the oil free of all taste defects. A tasting panel consists of between 8-12 judges.