Things you might want to know
* How to know the difference between Extra Virgin Olive Oil, and an imposter. If you retailer/supplier does not have this information available, you might wonder what it is they are trying to sell you.
Crucial Olive Oil Chemistry Definition Key
Oleic Acid: is a monounsaturated omega-9 fatty acid found in olive oil. Olive oil is generally higher in oleic acid than other vegetable fats. The range found in extra virgin olive oil is between 55-85%. Extra virgin olive oil high in oleic acid has greater resistance to oxidation.
FFA: Based on IOOC standards the maximum limit for free fatty acid in extra virgin olive oil is 0.8g per 100g or (.8%). A low FFA is desirable. Free fatty acid speaks to the condition of the fruit at the time of crush. The higher the FFA the greater the indication of poor quality fruit such as damaged, overripe, insect infestation, overheating during production or too much of a delay between harvest and crush.
Peroxide Value: Based on IOOC Standards the maximum peroxide value for extra virgin olive oil is 20. A very low peroxide value is desirable. Unsaturated free fatty acids react with oxygen and form peroxides, which create a series of chain reactions that generate volatile substances responsible for a typical musty/rancid oil smell. These reactions are accelerated by high temperature, light, and oxygen exposure.
Polyphenol Count: Polyphenols are a class of antioxidants found in a variety of foods. Polyphenols such as Oleuropein, Oleocanthal, and hydroxytyrosol impart intensity connected with pepper, bitterness and other desirable flavor characteristics. Recent studies indicate that these potent phenols are responsible for many of the health benefits associated with consuming fresh, high quality extra virgin olive oil. Phenols in olive oil decrease over time or when exposed to heat, oxygen and light. Consuming fresh, well made olive oil with high polyphenol content is crucial when looking to obtain the maximum health benefit commonly associated with consuming extra virgin olive oil.
New Testing Methods Based on Olive Oil Chemistry
DAGs Test/Score: Measures the proportion of two forms of diacylglycerol: 1,2 and 1,3. In oil freshly made from sound olives of good quality, the prevalent form of DAG is the 1,2 form where the fatty acids are bonded to a glycerol molecule in the 1 and 2 positions. The bond on the 2 position is weak and easily broken, leading to the migration of that 2 position fatty acid to the 3 position. This results in the much more stable 1,3 DAG. This makes the ration of 1,2 DAGs to the total DAG’s a good indicator of the quality of the olive fruit and the processing. It is also an indicator of the age of an oil, since the migration from 1,2 to 1,3 DAGs takes place naturally as the oil ages. Warmer storage temperatures, and higher free fatty acid levels will both accelerate this process, but DAGs are not affected by the short exposure to high heat that is characteristic of deodorizing (refining).