Olive Oil Chemistry Essentials

September 22, 2011

What You Should Know About Your Olive Oil

 

EXTRA VIRGIN describes a broad category of olive oils and should be viewed as a minimum standard and not an indication of superior quality.   While it is true that all high quality olive oil is extra virgin it is equally true that most olive oils labeled EXTRA VIRGIN are not high quality.  This is because the chemical and sensory parameters established for the grade are so broad that they include very average and mediocre as well as better qualities.  There are no established OBJECTIVE standards for extra virgin olive oil in the United States or the world for that matter.  Trade organizations like the IOOC, (International Olive Oil Council) NAOOA, (North American Olive Oil Association), COOC (California Olive Oil Council) are controlled by olive oil producers and not by any independent agency that represents the interests and welfare of the public.  While these trade associations publish standards they are absurdly low and seldom if ever enforced.  They function primarily as marketing associations for their respective members.   In addition, olive oil is perishable and is generally better when it isfresher.  Certain critical beneficial attributes like polyphenol levels, antioxidants, flavor and aromas decline over time while undesirable conditions like rancidity, and the formation of free radicals develop.  There is a direct correlation between good chemical attributes and nutrition, shelf life, and taste.  Olive oil is graded by both its attributes and its defects.  Two of the most important POSITIVE chemical attributes are Polyphenol counts, and Oleic acid levels.  The two most significant NEGATIVEchemical attributes are Free Fatty Acid levels and Peroxide values. In general, the higher the polyphenols counts and Oleic acid levels the better, and just the reverse for FFA’s and Peroxide values.

 

OLIVE OIL TERMS

POSITIVE ATTRIBUTES:

 

POLYPHENOLS -  Polyphenol intake has been associated with lower incidence of cancer and coronary heart disease (CHD) .  Polyphenols give olive oil its unique taste and improve its shelf life.  Some extra virgin olive oils contain far more, (up to 500% more) polyphenols than others.  The time of harvest, the variety, the method of extraction, and the management of the grove will affect the phenol count.   Processing or refining olive oil destroys the polyphenols in olive oil.  Refined olive oils like “pure olive oil”, “lite olive oil”, and “pomace olive oil” have little or no polyphenols, but the same amount of calories.  Heat, light, oxygen, and time cause polyphenol levels in olive oil to decline.  Unfortunaely, olive oil producers are not required to disclose the phenolic content in their olive oil.  The polyphenol count is not part of the codex of standards required by the IOOC, NAOOA, or the COOC.  As a general rule, the more robust oils have higher phenolic compounds than the milder oils.  Olive oils with less than 120 (as expressed by mg/kg) are considered low.  Virgin oils with a PPH count between 120 and 220 are considered medium.  Olive oils with PPH counts above 220 are considered HIGH in polyphenols.  Some of the more intense extra virgin olive oils will contain levels as high as 500.

OLEIC ACID – OMEGA-9 monounsaturated fat is found at varying concentrations in virgin olive oil.   It is believed to lower the risk of heart attack (CHD), arteriosclerosis, and cancer.  Virgin olive oils containing higher levels of OLEIC ACID tend to be more stable and hold up longer.  In this sense high oleic acid tends to act as a natural preservative. Oleic acid is measured in olive oil as a percentage.  The levels range from 45% to 80%+.   Extra virgin oils with low oleic acid levels and low polyphenol counts will have a markedly reduced shelf life.

SOME NEGATIVE INDICATORSIn this case less is more. 

FREE FATTY ACIDS- FFA’s is the measurement of free fatty acids in olive oil.  In a sense the FFA level is an indicator of the condition of the fruit at the time the oil was extracted.  It’s like a freshness quotient. When olives begin to decompose the level of free fatty acid increases. Fruit on the tree decays at a slower rate than fruit that has been removed from the stem.  Once the fruit has been picked or the skin is broken the fruit decomposes at an accelerated pace.  Ripeness plays a large role in the level of FFA’s.  Over ripe fruit produces a higher yield of oil to olive by weight but the free fatty acid increases as well.  This is why there is so much substandard olive oil produced.  Farmers are rewarded by a higher yield if they allow the fruit to become over ripe.

FFA’s increase over time.  Many olive oils that are close to the limit at the time of bottling become defective and outside the allowable limits soon after they are bottled or opened.  When olive oil is exposed to air, light, or heat decomposition increases until the oil is unfit for human consumption.  Rancid oil is harmful and a source of free radicals.  Olives that are crushed within 24 hours of picking will generally produce a higher grade of extra virgin olive oil provided the quality of the fruit and accepted methods of extraction are followed.  Though difficult, it is possible to crush the fruit within hours after picking.  Some farms have a mill on or close to the the groves and manage to crush the olives within a few hours after picking.  Fruit that is picked at the optimum level of ripeness and crushed within hours of picking will have much lower FFA  and peroxide levels.  In some cases as much as ten times lower than the IOOC standard.  It is entirely reasonable to expect that sound olives crushed in a timely fashion will produce oil with an FFA level of  .28% or less.  Extra virgin olive oils with FFA levels above .35% should not be considered premium extra virgin olive oil.   The IOOC allows an olive oil to be graded as extra virgin and have a FFA level of .8%.  The COOC allows the oil to have an FFA level of .5% and still be graded as extra virgin.

PEROXIDES- Peroxides are naturally occurring compounds in all edible oils.  They are essentially a measurement of rancidity or oxidation.  In the case of peroxides and olive oil, less is more.  Peroxide values increase over time and are indicators of the level of oxidation at the time of processing and increase according to storage conditions.  Poor storage conditions will cause rapid oxidation and rancidity.  The more oxygen, light and heat the oil is exposed to the faster the oil will become rancid.   Olive oil keeps far better in bulk than in tiny glass or clear plastic containers. High peroxide levels are an indication of poor processing practices, substandard fruit condition, old age, improper storage or any combination of these negative conditions.  The IOOC rules state that (IOOC codex) extra virgin olive oils must show a peroxides value under 20.(Expressed as meq O2/kg)

Veronica Foods

Delizia Olive Oil Company


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