Tuesday, 10 March 2015

You Know Some Facts About Cooking Oils?

You Know Some Facts About Cooking Oils?

One of the first things I tell people when they ask me about paleo and healthy eating is to sort out their fats and oils. It’s really worrying how many people still use canola or vegetable oil as their standard frying fat or how often I see people smoking the crap out of extra-virgin olive oil. Don’t even get me started on margarine!

That’s why this post is long overdue!. I’ve gone through dozens of websites, articles and papers to collate the list and the full breakdown of smoke points and cooking uses of common fats and oils but please let me know if you think something is incorrect or I should add extra information. I want to make this a useful resource for everyone.

Oils to avoid for better health:
While all oils are pure fat, not all fats are created equal. I won't get into details here, but saturated and trans-fatty acids seem to be the culprits if you have health concerns.  Margarine or Trans Fat Partially hydrogenated vegetable oils contain trans fatty acids. Read your food labels, if it says, "partially hydrogenated," try to avoid them.

They are present in all commercially made doughnuts, crackers, cookies, pastries, deep-fat fried foods (including those from all major "fast-food" chains), potato and corn chips, imitation cheeses, and confectionery fats found in frosting and candies. All of them have unsaturated fats which can be damaged at high temperature and converted to a trans fat. Look for fats labeled super-unsaturated (like flax seed) or monounsaturated (like olive and canola oil).  Polyunsaturated oils are also healthy choices.

What Is The Smoke Point:
Smoke point is the temperature to which an oil can be heated before it smokes and discolors indications of decomposition. If you are cooking with oil and it begins to smoke, you have reached its smoke point. At the smoke point, the oil begins to emit unpleasant odors and impart unsavory flavors to your meal. Watch out for the smoke point signs as it means you are getting close to the flash point, which is when the oil can erupt into flames. Knowing the smoke point warn you about the flash point and fire points. At the flash point, there are tiny wisps of flame; at the fire point a fire is blazing. The best oils for cooking and frying are those that have a high smoking point that is, they can be heated to high temperatures before burning.

A number of factors will decrease the smoke point of any fat:

-Combination of vegetable oils in products
-Presence of foreign properties (batter)
-Temperature to which oil is heated
-Presence of salt
-Number of times oil is used
-Length of time oil is heated
-Storage of oil (exposure to oxygen, light, temperature)

"Flash" And "Fire" Points
Other heat points for fats include "flash" and "fire" points at 600 and 700 degrees, respectively. Do not put out an oil fire with water, the water will splatter the burning oil and spread it more quickly. Smother the fire with a tight-fitting lid. If the fire has spread outside the pan, suffocate it with baking soda or a fire extinguisher formulated for oil fires.

Cooking oil that has reached boiling point (bubbling) is very dangerous. If the oil starts to boil, remove it from the heat source immediately. Simply turning off the heat source may not be enough to reduce the heat immediately for electric appliances, or cook tops because they retain heat even after they are turned off. An oil reaches its flash point at about 600°F. when tiny wisps of fire begin to leap from its surface. If the oil is heated to its fire point 700° F. for most oils, its surface will start vaporising and spontaneously ignite, surging up and out almost instantly.

Easy Tips:
The most accurate method of testing the temperature of oil for deep-frying is a deep-fat thermometer.  Make sure the bulb of your thermometer is completely immersed in the oil, but not touching the bottom of the pan. Otherwise, the reading could be affected. If you don’t have one, use the age-old method of dropping a square of bread into the hot oil; if it rises to the surface crackling and frying, the oil's hot enough. If it browns uniformly in:

-60 seconds, the temperature is 350 to 365°F
-40 seconds, the temperature is about 365 to 382°F

-20 seconds, the temperature is about 382 to 390°F

Oils for Frying
 The oil or fat you use for deep-frying should have a high smoke point  the temperature to which it can be heated without smoking. Butter and margarine have low smoke points, so they aren’t good for frying but work for light sauteing. The best oils for deep-frying and high temperatures are refined safflower and sunflower oils, peanut, safflower and soy oils. Refined almond, avocado and cottonseed oil are also great if you can find and afford them, and canola oil is usually not a problem either.

Remove food particles from used deep-frying oil by straining it through a coffee filter, or a sieve or funnel lined with a double layer of cheesecloth. Cover, tightly seal and refrigerate strained oil; it can then be used one more time.

The temperature of the fat is all-important if the fat isn’t hot enough, food will absorb fat and be greasy, oils that can't take the heat will get too hot, and burn. The normal temperature range for frying is 325°F to 375°F, however, it'd quite likely that higher temperatures of 375°F to 400°F also are used. Most foods cook rapidly in the 325°F to 375°F range and develop a golden color, crisp texture and good flavor. High-temperature frying leads to thinner crusts and less oil absorption. Foods fried in this normal temperature range absorb 8 to 25 percent oil. Frying time is longer at lower temperatures. Frying at lower temperatures results in lighter color, less flavor development and increased oil absorption.

Refined Cooking Oils
Refined Oils are extracted from clean oilseed / oil cakes by solvent extraction for further refining to produce clear oil, free from rancidity and foreign matter. These oils are used as medium cooking oils (225°F - 350°F), high cooking oils (350°F - 450°F), and deep-frying oils (greater than 450°F).

If the oil you buy is bland and pale, you can be certain that it has been fully refined, bleached, and deodorized. In essence, refined oils have negligible flavor and aroma which can be useful in delicately flavored dishes. Use for baking and sautéing, stir-fry and wok-fry, and oven cooking; to sear, brown, deep fry, fry and for tempura.

Unrefined Cooking Oils
Unrefined cooking oils: These oils are typically called salad oils and are used for salad dressings, marinades, and sauces or light cooking oils (light sautes and low heat baking). As a general rule, they should not be cooked at high temperatures. Use for light sautéing, low-heat baking, pressure cooking, sauces and salads. However, safflower oil is the one unrefined oil that can become hot enough to reach the temperature necessary for deep-frying.

Unrefined oil contains a full range of bioactive components that not only have healthful benefits and provide full-bodied flavor, but also make the oil more prone to oxidation. Using unrefined oils at temperatures above 320°F accelerates the oxidation of these oils.

Unrefined oils are processed by cold-pressed and expeller-pressed methods. Unrefined oils carry with them the true bouquet of olives, corn, sesame seeds, peanuts, soybeans, safflower, or whatever plant was the oil's original home. The strong flavors of unrefined oils can dominate whatever dish or baked good is made with them. Of course, strong flavor is not always a drawback; in some cases unrefined oils are used as flavoring agents. And, typically, where there is strong natural flavor and aroma, there is a higher amount of nutritional value. Best for medium heat temperature range: 212°F – 320°F.

Vegetable & seed oils
Together with high-fructose corn syrup and soy meat substitutes, the industrial revolution was responsible for the mass production of highly processed (polyunsaturated) vegetable and seed oils, such as soybean, canola and corn oil. While naturally occurring, minimally processed fats and oils (such as olive oil and butter) are a healthy source of energy and nutrients, highly processed seed oils contain high (read VERY HIGH) levels of omega-6 fatty acids, which when consumed in excess have detrimental health effects. Problem is these oils are present in nearly everything we eat nowadays. Grain-fed livestock, where a lot of meat produce comes from, is also high in omega-6.

A diet high in omega-6 is associated with an increase in inflammatory diseases such as cardiovascular disease, type 2 diabetes, rheumatoid arthritis, asthma and cancer to mention a few.
In addition to omega-6 fatty acids, most polyunsaturated oils are highly prone to oxidation and rancidity, which turns these so-called ‘heart healthy’ oils to toxic liquids.

And although some of them have a high smoking point, making them seemingly suitable for frying and cooking at high temperatures, their chemical structure is so unstable (again, due to the fatty acid ratio) that they really shouldn’t be cooked with at all. For these reasons, it’s best to avoid the following fats and oils: corn, cottonseed, soybean, canola, safflower, sunflower, peanut, grape seed, vegetable and margarine, which is made from aforementioned oils.

What are the good fats & oils?
The paleo diet embraces saturated fats and healthy plant-based oils and avoids highly refined and processed polyunsaturated oils, such as those mentioned above,  due to their toxic properties and high omega-6 fatty acids. Your fat intake should come from meat, seafood, eggs, nuts, avocados and fats and oils used in food preparation.

It’s important to know which type of fat or oil is best suited to which food preparation method. Some things to keep in mind are:

*Saturated fat is typically more heat stable and doesn’t oxidate as quickly as monounsaturated and polyunsaturated fats, which makes it more suitable for frying and other high temperature cooking.
*Nut oils and olive oil are more fragile and can be cooked with but are best used unheated to retain the most antioxidants, vitamins and flavour.
*Refined oils will usually have a higher smoking point. Ideally, they should be expeller-pressed, which indicates that the oil was extracted using a mechanical process rather than with heat and chemicals. These are best for high temperature cooking such as deep-frying.

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Sajid

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