Thursday, November 18, 2010


One food that appears in almost all kitchens is cooking oil. It’s indispensable for frying, baking, and seasoning our foods. While most of us wouldn’t think of preparing meals without a measure of oil for food enhancement, there’s still a lot of discussion about the role of oil in our diet. It also happens to be one of the more expensive items on our grocery list because it comes to us as a processed food. So, after reading a bit about the subject, I thought that it would be good to review what’s known about the health and culinary qualities of cooking oils.

And here’s some general info on cooking oils.
All common cooking oils such as canola, corn, olive, pumpkin seed, peanut, and soy are made from plants and are usually liquid at room temperature. Coconut oil and palm oil are semi-solid are room temperature. They can be sold as just one specific type of oil or as a blend. The price of different vegetable oils varies a lot. Despite some distinctions, they are all considered to be healthy oils in that they are high in non-saturated fats and contain antioxidants.

Now there are, of course, animal fats that are used in cooking. Those are the greases and butter that we can buy already processed or can process at home. All the animal fats are heavily saturated. Nutrition experts agree that it’s important to limit saturated fat but not eliminate it because it’s required for a healthy body and brain. So, while animal fats are considered (by many) to be great for making tasty food – like bacon grease in beans or greens or chicken broth in soups and stews, we should be careful about the quantities that we eat.

But there are some rather obvious conflicts on the topic of cooking oils. While most of us use them, we know that they contribute heavily to our already calorie-loaded diets – with each teasoon of fat representing about 125 calories. And, we’ve heard that that fried foods also may contain disease-causing substances that form in oils when they reach high temperatures. What’s more, some studies have shown that frequent exposure to frying fumes is a cause of respiratory diseases in both restaurant and home cooks. So, all of this is worrisome. Is it necessary to avoid most fried foods and prefer low-fat diets? Or can we safely continue our current use of cooking oil?

What are some safety rules for cooking oils?Vegetable oils are high in non-saturated fats, have antioxidants, and are generally considered to be healthy when used properly. (The FDA says that the total of fats should not make up more than 30% of the diet.) The bulk of the fats we use in the kitchen should come from plants, especially if we find out, or suspect, that we have high cholesterol levels. All vegetable oils are fragile and need to be stored in airtight containers away from contact with direct light. Also, to be sure, you should smell or taste oils before you use them. Throw out any stale or rancid oil. (You can burn it as fuel for candles - best burned in the outdoors because they smoke a lot.)

Used fried oil, if not burned, can be a part of other preparations. Do not use any kind of leftover oil for frying again as it becomes carcinogenic. Never add fried oil to fresh oil. Avoid heating oils to temperatures beyond their smoking point. The table below shows some of the plant oils that safely withstand higher temperatures (adapted from a chart in Wikipedia):

Safe - higher smoke point (from 350F to 450F)
Olive Oil
Canola Oil
Peanut Oil
Safflower Oil
Palm Oil (suspect by some for having a higher proportion of saturated fats.)

Caution - Moderate smoke point (only up to 350F)
Sesame Oil
Corn Oil
Soybean oil
Coconut Oil

Most vegetable oils are best if they are used in the space of one or two months after opening. Their antioxidant activity decreases month by month. So, buy smaller containers that you’ll use up in a few weeks. Home-processed animal fats - like ghee (clarified butter) and leftover bacon grease - should be refrigerated and used within a week. Unlike other dietary fats, trans fats are industrial-produced monsters that are known risks to health, especially coronary heart disease. Stay far away from them and the same goes for hydrogenated and partially-hydrogenated fats (and the products that contain them).

Margarine in all its forms, along with real butter and animal grease, are not recommended for frying. Animal fats should only be heated to boiling temperature as part of soups and stews. It is also best to reduce your intake of high-fat, calorie-dense foods like butter (80% fat) and mayonnaise (75-80% fat).

So, should we be saving money on oils?
Choice of oils depends on both taste and price. Some cooks like the distinctive fruity, spicy or nutty oils such as those associated with olive, sesame, and coconut. But these flavors usually are found in the higher cost oils. Canola oil is inexpensive and at the same time is neutral in flavor and a good source of antioxidants. It has about the same cost as soy oil – a nickel to a dime a tablespoon. Extra-virgin olive oils and most others with special flavors can cost up to a dollar a tablespoon. That’s a lot of difference, so your budget may be the defining factor at the grocery aisle.

But, consider this. All oils tend to lose their special flavor after exposure to high temperatures. Even expert judges may be fooled about the qualities of high-priced oils when they are heated. So, the general rule is to use the expensive oil you like for drizzling on salads but pick a cheaper one for frying. You can also do a combo – less expensive oil for frying and then add a tiny bit of the high priced stuff – like extra virgin olive oil - just before serving.

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