As a result of cowpooling a grass-fed animal, I've been reading a lot about conjugated linoleic acid. However, I'm confused about whether CLA is a saturated, monounsaturated, or polyunsaturated fat? I'm particularly curious about whether it gets oxidized when you render tallow. Thanks in advance!
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CLA is a PUFA but it interestingly has a trans bond making it a Trans Fat albeit a healthy trans fat (likely because all the double bonds aren't Trans, there's a Cis bond also). [The difference between tran and cis bonds is that trans do not cause the molecule to snake but allow it to remain straight, where as the cis bond snakes the molecule making it so they can't pack tightly together. The body seems to expect PUFAs to snake and as hell of a time with PUFAs that are all straight, ie trans. At least that's the going theory.] A quick chemistry lesson *All trans means is the two hydrogens are on different side of the carbons that are double bonded and cis means two hydrogens are on the same side of the double bonded carbons. A carbon can have four bonds. In a fat, two of those bonds are taken up by neighboring carbons (except on the ends) and two are taken up by hydrogens or double bonds. If there's a double bond the two carbons that are double bonded together just have one hydrogen. If that hydrogen is one the same side both on top or both on bottom it's called Cis; if the carbons are on opposite sides it's called trans. All it means is that the bond angles are different which in turns means that boiling point and intramolecular forces are different. Cis
Trans
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Curated Wellness is right, but a more general answer is to go to wikipedia and type in your molecule. They generally have pictures of them (if they don't then the NIST Webbook is great, but it's harder to user - it's for chemists). If we look at the picture of CLA on that page (http://en.wikipedia.org/wiki/Conjugated_linoleic_acid), which is bigger here (http://en.wikipedia.org/wiki/File:Rumenic_acid.svg), you'll see two double bonds in the upper right of the picture. Every double bonded carbon (not the double bonded C=O) is a point of unsaturation. So: no double bonds = saturated, one double bond = MUFA, more than one double bond = PUFA. Additional chemistry nerd information: The closer the double bonds are to one another (like here where they're only separated by one bond), the easier it is to oxidize them - that's because when you pull a H off of the double bonded molecule the resultant free radical is more stable. (The reason that this is called "conjugated" linoleic acid is that the double bonds are "conjugated" which in chemistry speak means alternating with single bonds). Chemists always talk about the location of interesting parts of a molecule based on the "most important carbon" and there are rules for designating the most important carbon. In fatty acids, that carbon in the acid part, which is that carbon way to the left, the COOH carbon. That carbon is called the "alpha" carbon, the one next to it is the "beta", and so on. (you've probably seen skin cream commercials where they talk about "alpha hydroxy" that means an hydroxyl group on the alpha carbon). Anyway, biochemists like to talk about the other end of the molecule farthest away from the most important carbon, and since the most important carbon is "alpha", they call the one farthest away "omega". Now, you can see where omega-3 and omega-6 fats get their name. If the first double bond is on the 3rd carbon from the end, it's the omega-3 carbon and if the first double bond is on the 6th from the end it's on the omega-6 carbon. |
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