DEAR DR. BLONZ: Due to your frequent mentions of olive oil, I have shifted over to it as our preferred oil for cooking. I have a question about certain kinds of olive oil, especially the extra virgin olive oils that have an occasional peppery bite when they go down my throat. Please explain why the oils taste this way, and whether such oils are safe to use. -- M.R., Sun City, Ariz.
DEAR M.R.: The peppery bite is not a sign that the oil has gone bad. It's actually a positive attribute, reflecting the presence of the olives' beneficial phytochemicals. But first, some background.
I have had a number of opportunities to watch olive oil being made in Italy, in Greece and in the United States. For those of you unfamiliar with the process, oil gets removed from olives by using specialized presses. The oil that comes out with the least amount of pressure is the "extra virgin" olive oil. This is the darkest, most delicate and flavorful oil, and it is the most expensive.
As pressure is gradually increased the next oil to come out is the "virgin" olive oil. It has less color, but still contains some of the olive's fruitiness. The remaining oil would be the standard, or regular olive oil. Pale in color, this oil has only a hint of olive flavor. Some companies in the U.S. make "light" olive oils that have no distinctive olive flavor whatsoever. Other companies blend the different types or oil to help achieve a more standardized olive flavor. The fatty acids in all the olive oils are approximately 14 percent saturated, 77 percent monounsaturated and 9 percent polyunsaturated.
You mention a concern about safety. Any oil can go rancid if stored the wrong way. Rancidity occurs when the oil reacts with oxygen-forming substances, and this can give the oil a noticeably unpleasant smell and taste. Aside from the off taste, the consumption of oxidized oil can also represent a health risk. The higher the proportion of unsaturated fatty acids, the easier it is for oil to oxidize, but it is heat and exposure to sun and air that are the critical factors for this type of breakdown. This means that oils should always be stored away from sun and heat in a well-sealed bottle.
The olive is the fruit of the olive tree, and the role of the oil is to nourish the developing seed until it can begin to grow on its own. If rancid, the seed would be less likely to grow, so nature equips the olive with a number of protective components: vitamin E and a variety of antioxidant compounds known as polyphenols. These compounds protect the olive and can provide beneficial attributes for us as well.
The people I have spoken with who produce extra virgin olive oil speak with understandable pride about their olives and their oil. They hasten to point out that all olive oil is not the same; it's only the extra virgin olive oil that has the right stuff. Once you understand that it is the extra virgin olive oil that contains the greatest compliment of beneficial phytochemicals, you understand their logic and gain a new appreciation for the various flavors, aromas and the occasional peppery bite.
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