nora (aloof3) wrote in ed_ucate,
nora
aloof3
ed_ucate

Fats for Cooking

In anticipation of possibly being invited to the_ed_kitchen at some point, I was flipping through the one cook book I own, I'm Just Here for the Food by Food Network's Alton Brown. If any of you watch his show, Good Eats, you probably know it's very informitive rather than just making up new dishes like most other cooking shows. This book follows the same idea - it has pretty basic recipes along with a ton of information on cooking styles (which is actually how the book is mapped out instead of by food) and just how cooking works in general. As he says, "Sure, [recipes] can get us where we're going, but that doesn't mean we know where we are when we get there."

I typed up this little part because I thought it had some really great information about fats that was easy to read. Now, I know a lot of you may never touch any oil or fats when you cook, but that doesn't mean that it's not a good read, and it doesn't mean I'm advocating the use of butter or something. I just like knowing why.  I also want to mention that this little part was in a section about frying, which is why smoke points, browning, or crispyness (?) are mentioned, but that doesn't really matter much as far as the information goes.  

Please excuse any typos I didn't catch. I can't read or write.

"Fat is one of the body’s basic nutrients. According to Harold McGee in his On Food and Cooking, fats account for about 10 percent of daily caloric intake in developing countries while in affluent societies like our own the figure is more like 40 percent.

 

As consumers, we became saturated with fat talk years ago when doctors decided that fat was bad. Since Americans have been steadily plumping up for the last few decades, this wasn’t a great leap of quantum thinking, But then somebody figured out that different fats elicit different responses in the body, depending on their saturation. Thus began the great dialogue and even greater confusing regarding the nature of saturated, monounsaturated, and polyunsaturated fats. As for cholesterol, well, let’s just say that the amount of cholesterol in the foods we consume is not necessarily reflected in the amount of serum cholesterol in our bloodstream. But, just in case you’ve been buying one particular brand of vegetable oil simply because the container proudly proclaims it “cholesterol free,” you can feel safe and secure in knowing that it’s true. Of course, there’s no such thing as a vegetable oil containing cholesterol. Only animal products, such as lard, contain cholesterol.

 

All culinary fats are called triglycerides. The term refers to the fats’ molecular architecture, comprising three fatty acids that are esterified, or hitched to a glycerine molecule. The structure of these fatty asids greatly determines how the fat is going to act when it gets into the culinary (and biological) food chain. Although there are a lot of different fatty acids (a whole lot actually), they all fall into one of three categories: saturated, monounsaturated, and polyunsaturated.

 

The fatty acid is basically a long chain of carbon atoms. Besides being anchored to the carbon in front as well as behind, each carbon has two chemical arms that can each hold a hydrogen atom. When all the carbons in a chain have their hands full of hydrogen, it is saturated, meaning that it can hold no more. Fats high in this kind of fat tend to be solid at room temperature, and they make cardiologists nervous.

 

If two adjoining carbons on a chain are lacking a hydrogen (this always happens in twos; there are never singles or threesomes), they join hands, creating a double bond. If this occurs just once on a chain, the fatty acid is referred to as monounsaturated, meaning hat there is a vacancy but only one. If there are more vacancies along the chain, it is polyunsaturated.

 

All fats contain all three types of fatty acids. What decides how a fat is to be classified depends on how many of each kind there are.

 

Folks in lab coats are still duking out whether mono- or polyunsaturates are better for us. Culinarily speaking, things are a little more cut and dry. But there are still choices and trade offs. (see table below)

 

Fats high in saturated fatty acids create wonderfully crisp fried foods, but saturated fats have relatively low smoke points so you don’t get much use out of them and they’re not very good for you.  Saturated fats come from animal sources and can hold their shape at room temperature. The most commonly used saturated fats are butter, lard, and suet.

 

Unsaturated fats don’t fry up quite as nicely as oils high in saturated fats, but they have high smoke points so they can be used more than once (if you’re careful with them). Unsaturated fats are primarily derived from plants and are usually in the form of an oil. Monounsaturated fats include olive oil and peanut oil. These fats are known to air in the reduction of LDL cholesterol levels. Fats high in monounsaturates are ten times less shelf-stable than saturated fats and have low smoke points.

 

Polyunsaturated fats include safflower, sunflower, soybean, corn, and sesame oils. These fats are also better for our health but because their carbon chains have empty hands on them, nasty molecules (oxygen, for instance) can dock with the fat, making it go rancid quickly.

 

Just to make things a little more complicated, there are hydrogenated fats and trans fatty acids, both results of tinkering by the big, hairless monkey.

 

In order to make a polyunsaturated fat solid at room temperature or resistant to rancidity, hydrogen is pushed into the molecule so that those empty seats won’t be taken up by undesirable substances. Fatty acids receiving this elemental transfusion straighten out physically, which makes it easier for the fat to lock up with its neighbor. The result is a fat that’s solid at room temperature and opaque rather than clear. Vegetable shortening is a good example of this kind of fat. Unfortunately, any health advantages that might have been gained by the unsaturated nature of the fat is blown out of the water by the fact that the added hydrogen essentially saturates the fat. A trans fatty acid is simply a polyunsaturate that has been partially hydrogenated. Most nonbutter, buttery spreads employ trans fatty acids.

 

“Fat” here is a blanket term for triglycerides. Technically speaking any triglyceride that is solid at room temperature is called “fat.” Any triglyceride that’s liquid at room temperature is called an oil. There are two exceptions: palm oil and coconut oil, both of which are solid at room temperature but for some reason are still referred to as oils rather than fats."

FAT SATURATIONS (%)        Saturated; Monounsaturated; Polyunsaturated

Canola or Grapeseed - 6; 65; 29

Walnut - 9; 28; 63

Safflower - 10; 13; 77

Sunflower - 12; 19; 69

Corn - 14; 28; 58

Soybean - 15; 24; 61

Sesame - 15; 41; 44

Olive - 15; 73; 12

Peanut - 18; 49; 33

Cottonseed - 27; 19; 54

Palm - 54; 38; 8

Coconut - 92; 6; 2

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