Cut trans fats by using fully hydrogenated shortening

Q. Will you please explain why using hydrogenated shortening is any better than using partially hydrogenated shortening? I see that my brand is now hydrogenated rather than partially hydrogenated. Is it better of worse for cooking?

-- M.A.P., via e-mail

A. The quick explanation is that a (fully) hydrogenated shortening does not have any trans fats.

Imagine a road stretching between an unprocessed, unsaturated vegetable oil and a solid block of hydrogenated fat. On such a road, a partially hydrogenated fat is a stop somewhere in the middle. Food processors require fats for different purposes, and the point at which you stop along this continuum depends on the intended use. A partially hydrogenated fat used for deep frying is different than one used in baking, or one used to make breading or candy coatings.

The key issue here is that the process of partial hydrogenation creates trans fatty acids, or TFAs, which are unsaturated fatty acids that have an unusual structure that causes them to misbehave in the body.

Blends with different proportions of TFAs might be more spreadable, have an increased shelf life or have some other desired feature, but the advantages of these artificial fats are all on the processor side of the equation. They provide no health benefits for the human body. In fact, evidence continues to mount that associates TFAs with a number of health problems, including heart disease and cancer.

Due to this lack of an upside, the Food and Drug Administration began requiring trans fats to be declared on food labels. With the negatives associated with trans fats, and the advent of having to reveal the number of grams per serving, food processors sought other methods to make their spreadable fats.

In one method, known as interesterification, food processors use oils together with fully hydrogenated fats and create a mixture with the desired characteristics. It's not something you can do at home with a measuring cup. This type of reconfiguration involves shuffling fatty acids around on triglycerides using enzymes or chemical catalysts. Many of the new trans-fat free shortenings on the market are made this way.

Interesterification has been available to food processors for a while, but it was less costly to keep using partial hydrogenation, and there was no public outcry for alternatives, so no changes were made. The fact that the fully hydrogenated product has no trans fats means there's no trans fats to declare on the Nutrition Facts label.

Now we know this new shortening has no trans fats -- and that's good -- but the jury is still out as to whether the use of interesterified fats might give rise to other health issues. There's also the possibility that fats naturally high in saturates, such as palm or coconut, might be the way to go. Those tropical oils, long given a public-relations black eye, may yet get their green card.

As for whether it's any better or worse in the kitchen, the new shortening products have undergone performance testing, so you'd expect them to be comparable. Just as there are brand-to-brand variances with other cooking ingredients, you may need to do some testing to find the shortening that works best with your recipes.