Olive Oil Chemistry Definitions

Crush Date: Rarely do any suppliers post the actual crush date of their olive oil. This is because most all imported Olive Oil in the USA is older than you might think. Fresh Harvest always posts the crush date on our ultra-premium extra virgin olive oil. A good EVOO should be consumed no longer than 14 months from the crush date for maximum health benefits.

Oleic Acid: A higher level is better! Oleic acid is responsible for some of the health benefits of EVOO, and its high resistance to free radicals helps to slow down the spread of damaging chemical chain-reactions. Because of its high degree of resistance to attack by oxygen free radicals, higher levels of oleic acid in an olive oil help keep it fresher for longer, by preventing the formation of peroxidized (rancid) fats. Our bodies absorb any peroxidized fats that we consume and incorporate them into our cells. Oleic acid’s superior resistance to free radical attacks protects our cell membranes, proteins, and DNA from being damaged, as it protects the oil from spoiling. Substituting oleic acid for saturated fatty acids in animal fats improves cholesterol balance,[i] and research also suggests that oleic acid may have more specific health benefits, such as the ability to help regulate healthy blood pressure by altering cellular signaling. For these and other reasons, the US FDA has approved the health claim that “Limited and not conclusive scientific evidence suggests that eating about 2 tablespoons (23 grams) of olive oil daily may reduce the risk of coronary heart disease due to the monounsaturated fat in olive oil.”

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. We harvest and crush within 4-6 hours or less.

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.

Biophenols: As science developed, we have learned that a significant amount of health attributes related to extra virgin olive oil are not only linked to its profile rich in monounsaturated fatty acids but also to its biophenol content. In the early days, total biophenol content was simply measured by measuring the reaction of this complex group of substances with a colorant (Folin-Ciocalteau). The darker the blue colour developed from the reaction, the higher the level of biophenols. The actual level of biophenols was determined by a comparative scale measuring how much colour was developed by known quantities of a standard phenol (either caffeic acid or garlic acid). Even when this method provided a reasonable indication, it was far from perfect as all different phenols react to the colorant in different ways. Furthermore, it did not tell us anything about the different groups of biophenols. As we know now, some of those biophenols have very specific health and sensory properties (i.e. Oleocanthal, which has important antinflammatory action and it is responsible for the pungent feeling on the back of the throat).

Even when there are no limit for polyphenols in international standards, they are very effective antioxidants in olive oil and contribute significantly to oxidative stability, shelf life and health claims. Given the growing importance of these antioxidants, a new and more precise measuring method has been developed. This method utilises High Performance Liquid Chromatography (HPLC). High Performance Liquid Chromatography (HPLC) is a form of column chromatography that pumps a sample mixture or analyte (in this case EVOO) in a solvent (known as the mobile phase) at high pressure through a column with chromatographic packing material (stationary phase). The sample is carried by a moving carrier gas stream of helium or nitrogen. HPLC has the ability to separate, and identify compounds that are present in any sample that can be dissolved in a liquid in trace concentrations as low as parts per trillion. Sample retention time (the time that it takes for each biophenol to exit the column) will vary depending on the interaction between the stationary phase, the molecules being analyzed, and the solvent, or solvents used. As the sample passes through the column it interacts between the two phases at different rate, primarily due to different polarities in the analytes. Analytes that have the least amount of interaction with the stationary phase or the most amount of interaction with the mobile phase will exit the column faster. A detector at the point of exit determines when and how much of each biophenol is sensed. The total amount of biophenols in this method is determined by adding the individual quantities of each measured biophenol.

There are typically more than 20 different biophenols in extra virgin olive oil. The prevalent classes of hydrophilic phenols found in EVOO are phenolic alcohols and acids (i.e. Hydroxytyrosol and vanillic acid), flavonoids (i.e. luteonin), lignans (i.e. pinoresinol) and secoiridoids. Among these substances the last two classes include the most concentrate phenols of EVOO. Secoiridoids, like aglycone derivatives of oleuropein, demethyloleuropein and ligstroside, are present in olive fruit as most abundant EVOO phenolic antioxidants. Several important biological properties (antioxidant, anti-inflammatory, chemopreventive and anti-cancer) and the characteristic pungent and bitter tasty properties have been attributed to EVOO phenols. (Leandro Ravetti – Technical Director – Boundary Bend)

The term “biophenols” was first used in 1996 to denote bioactive phenols in olives replacing the more common and less chemically accurate term “polyphenols”. “Biophenols” has started gaining popularity beyond olive chemistry and currently used by researchers to refer to plant phenols in general. Biophenols constitute the largest group of secondary plant metabolites with ubiquitous presence in plants and wide spectrum of biological activities. During the last three decades, biophenols have seized scientific attention, lured industry and attracted consumers’ interest due to their antioxidative potential in preservation of food and maintaining human health.The ability of food to maintain health and prevent disease is a common belief and a proven scientific fact. However, the power of food constituents to treat and cure ailments is a contested concept. The idea of using food for medication is not novel. Hippocrates famous quote, said centuries ago, “Let thy food be thy medicine and medicine be thy food”. Biophenols are highly prized for their free radical scavenging and antioxidant activities. Medical research is showing that Biophenols (sometimes called Polyphenols) fight Cancer, Stroke, Heart Disease and a host of other medical issues, including Alzheimers, by significant margins. 

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).

PPP Test/Score: This test was developed to measure the degradation of chlorophyll in olive oil. This degradation of chlorophylls to pyropheophytin was found to take place at a predictable pace, making it possible to gain information about the age of an olive oil. The rate at which the degradation occurs can be accelerated by even short periods of high temperatures – such as that which is utilized during the deodorizing or soft column refining process – making it a useful indicator of the presence of deodorized olive oil as well as the age of the oil. Recent studies show that many grocery store oils fail PPP (17% is considered falling in the voluntary Australian standard). Freshly made oil should have a PPP of close to zero.

Soft column refining is generally used to strip out sensory defects  and otherwise neutralize some chemical parameters in old oils or oils made from over-ripe and fermented (late season) olives so that they can pass typical authenticity tests, undetected. PPP are highly influenced by heat and then also by light. In ideal storage conditions, they should only increase between 6-8% per year! An oil with an extremely high PPP is a clear indication that “something” is wrong or amiss. Either the oil is severely aged, deodorized or has had continuous light exposure (clear packaging!) for extended time periods and/or higher than normal storage temperatures.

A-Tocopherals: A nutrient that the body needs in small amounts to stay healthy and work the way it should. It is fat-soluble (can dissolve in fats and oils) and is found in seeds, nuts, leafy green vegetables, and vegetable oils. Alpha-tocopherol boosts the immune system and helps keep blood clots from forming. It also helps prevent cell damage caused by free radicals (highly reactive chemicals). Alpha-tocopherol is being studied in the prevention and treatment of some types of cancer. It is a type of antioxidant. Also called vitamin E.

​Squalene: Squalene is a natural organic compound which is part of our tissues. It is a polyunsaturated hydrocarbon and its molecular structure resembles that of vitamin E.  However Squalene contains four additional groups of isoprenoids, which are very potent natural antioxidants.