Why is light harmful for olive oil?

Question

So? regards

Answer 1

Oh yes, light is certainly harmful for olive oil; in fact for most liquid vegetable oil.

The easiest technical reason is that olive oil is a monosaturated fat - where there is a double bond between two carbons in a long chain of carbons. Light induces the breakage of this double bond into a single bond and in the process adding two additional hydrogens to the respective carbons. This is common known as the oil getting rancid; the proper term is lipid peroxidation(if you are interested, look it under in wikipedia.)

And then you might ask what is so bad of this process. The reason olive oil is conducive to health is because of the presence of this double bond. Saturated oils, from meat and dairy product, are "saturated" meaning there is no double bond anywhere and "maximum" number of hydrogens are attached to the carbons on the chain( thus the chain is saturated with hydrogen atoms).

What is so bad about saturated oil is that it allows very tight packing of oils and the oil becomes plaque in the arterial wall causing circulatory disease.

On the other hand, this kink(double bond) in unsaturated oil allows greater freedom for the oil molecule to move around and not causing plaque.

This is a simplified technical explanation, but sufficient enough for you to understand some basic concepts.

Answer 2

Light is not harmful, but light will eventually reduce the useful antioxidant effects of olive oil.
When you buy it in bulk, and I know few people who do that as a rule, it usually comes in a can and it is best to keep that can in a cool place, such as a cool dry dark room. Pour off only a small portion that you keep close to your cooking area for everyday use. Most of us just buy them in the small containers and those are used up fast so it is ok to keep them next to the stove within arms reach.
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Many people ask about the proper storage temperature for olive oil. Heat speeds up all of the above reactions. Keeping your oil next to the stove in a clear bottle will quickly age it. Better to keep a large container in a dark, cool cupboard and pour a small amount into a dispenser for everyday use. Olive oil can be put into the refrigerator or freezer without harm, which will greatly extend its shelf life.

Answer 3

I've never heard such a thing. Most olive oil is sold in
transparent plastic jugs.
Virgin Oil olive although is sometimes sold in darker jugs.
If the sunlight is bad for it , it would be that the light causes
the chemical composition of it to change and it would spoil.

Answer 4

All oils can break down and become rancid. Light accelerates this process. Olive oil is particularly susceptible to this since it has a unique flavor.

For a super technical explanation see:
http://www.oliveoilsource.com/olivechemistry.htm
a simpler one:
http://whatscookingamerica.net/Q-A/OliveOilRancid.htm

Answer 5

Olive oil for cooking? I don't know why light would be bad for it. All the great cooks I know and even myself keep it out on the counter near the stove at all times.

Answer 6

Sounds suspicious. The olive oil I cook with still has the same excellent quality as the day I bought it. Ciao.

Answer 7

Light can break down fragile fat molecules. The oxidation or breakdown of fat causes the once harmless fat molecule into a harmful substance that may cause cancer or otherwise harm the body.