Trans Fats and You - Part 2  

Want to Use This Graphic?[Read part 1 HERE]

Trans fats are found in partially hydrogenated oils, but how are they made?

In the old days, oils were extracted from the fruit, seed, or nuts that contain them, with slow-moving, heavy, stone presses that generated very little, if any, heat. But today, it's done by first crushing the seeds and then heating them to 230 degrees to get the oil flowing before squeezing the crushed, hot, seeds at 10 to 20 tons of pressure per inch --this generates even higher temperatures.

All this heat and pressure causes the weak carbon bonds of unsaturated fatty acids, especially triple unsaturated linolenic acid (an omega 3), to break down and create free radicals. Not only that, but antioxidants (like vitamin E), that are supposed to defend the body against these free radicals, are destroyed by the high heat and pressure.

Throughout the process, the oils are exposed to damaging light and oxygen. The combination of all these things almost guarantee the oils will be rancid. But don't worry, you'll never be able to tell by the time they're through processing it.

We're not done yet. In order to get every last drop of oil from the crushed seeds, processors take the pulp and add one of a number of solvents — usually hexane, a known carcinogen, but there are other equally nasty choices. Solvents also act on the pesticides that are on the seeds, causing them to dissolve off the seeds and into the oil.

These solvents are not, themselves, suitable for human consumption so they have to try to remove them. They do this by boiling the oil (more heat) to get the solvents to evaporate. Up to 100 parts per million remain in the oil.

Next BHT and BHA, both suspected of causing cancer and brain damage, are often added to these oils to replace the natural preservatives (like vitamin E) that were destroyed.

Up 'til now, I've just been telling you how the liquid vegetable oils (corn oil, soybean oil, canola oil, etc.) on the grocery store shelves are produced. But you needed to know this before we moved on to hydrogenation.

Hydrogenation is the process that turns polyunsaturated oils which are normally liquid at room temperature, into an oil that is solid at room temperature, like margarine and shortening.

Manufacturers start with the cheapest oils (that would be soy, corn, cottonseed or canola, which are already rancid from the extraction process described above) and they add tiny metal particles --usually nickel oxide. The oil with the nickel in it is then subjected to hydrogen gas in a high-pressure, high-temperature reactor. I don't really know how the nickle oxide is removed from the hardened oil. (If anyone has info on this, please let me know.)

Soap-like emulsifiers and starch are also squeezed into the mixture to give it a better consistency. Then, again, under high heat and pressure, the oil is steam-cleaned. The steam cleaning may be how the nickle is removed, but its main purpose is to deodorize the oil, which by this time has a very unpleasant oder and color.

For example, margarine's color at this point in the process, is grey. This color is removed by bleach and then dyes and strong flavorings are added to make it resemble butter. Finally, the mixture is compressed and packaged in blocks or tubs and sold as a "healthy" alternative to butter.

[Read part 3 HERE]


This entry was posted on Wednesday, September 24, 2008 and is filed under . You can leave a response and follow any responses to this entry through the Subscribe to: Post Comments (Atom) .