Extra virgin olive oil decreases in flavour and health benefits over time. Fresh crushed olive oil is like fresh squeezed fruit juice in that it contains the most flavour and nutrients. Old, poorly made and improperly stored extra virgin olive oil yields fewer if any health benefits and undesirable flavour.
Becoming intimately familiar with a particular extra virgin olive oil's flavour characteristics and chemistry i.e. antioxidant content, oleic acid, FFA, and crush date will help you make an educated decision about which olive oil is right for you.
Crucial Olive Oil Definitions
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 55-83%. 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 tempature, 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 flavour 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.