Unsaponified matter

[avinogradova]

Does anyone know anything about the significance and application of unsaponified matter in oils? Does it help to protect against UV? Any other applications?

[UC]

That largely depends what the unsaponifiables are. They could be an extremely large number of things and are going to depend largely on what kind of oil it is. In oils, the percentage is usually quite low, so I would not suspect any significant effects unless isolated or if a ton of the oil is consumed.

 

Google shows some arthritis treatment with avocado and soybean unsaponifiables. I've no idea if it's actually helpful or another junk health product. It looks to be credible, but I don't have the time to dig through sites and references.

[CaptainPanic]

Pure vegetable oil consists of triglyceride esters of fatty acids (that's a glycerol with on the -OH spots 3 ester groups of the fatty acid).

It very often also contains the free fatty acids. The fatty acids can saponify (meaning that if you add a base (e.g. NaOH) it will form a salt, which is commonly known as "Soap". Yes, that's the stuff you can theoretically wash your hands with, although much better soaps exist.

 

This is an important thing in biodiesel production. (The catalyst in that reaction is NaOH, and the presence of fatty acids will react with the catalyst, thus making it inactive).

 

I have no clue about UV protection, but you can always just throw olive oil over your skin, and sit in the sun. If you still get a sunburn, then it has no effect

[John Cuthber]

Captain,

Did you realise that if it were true that those were the only components of vegetable oils then there would be no unsaponifiable stuff?

In real fats there are things like phytosterols and the fat soluble vitamins.

At least some of those would act as UV screens and free radical traps.

How healthy these are is probably open to debate- too large a dose of some vitamis is seriously toxic, but if you were short of them then this stuff could be a lifesaver. For most of us the answer is probably somewher in between.

[CaptainPanic]

Umm... yeah... I probably should have checked some definitions before jumping into this discussion. I learned (regarding biodiesel):

Triglycerides, as far as I know, are unsaponifiable.

Fatty acids are saponifiable (because they can form a soap).

 

It might be possible to make a soap from the triglycerides too, through different synthesis... and I don't know it.

 

 

I wrote that there are triglycerides and fatty acids in vegetable oil, and that the fatty acids are saponifiable. There are more components, as almost always with things of bio-origin.

I meant to say that for biodiesel production, the triglycerides (which do make up the majority of pure vegetable oil, but not 100%) are the good stuff, although you can use fatty acids too.

In used kitchen oil, the fatty acids can make up a much larger fraction, and you can still use that for biodiesel, although the synthesis is a bit different.

 

It is common to to a number of tests (by titration) to determine just how much fatty acid is there.

 

Thanks, John Cuthber, for making me explain myself a bit better.

Edited February 6, 2009 by CaptainPanic