August 2018 Newsletter | Kristin Zelhart, Nutrition, Standards and Certification Manager
With National Avocado Day this past Tuesday, I was inspired to talk about fats! In the Epicurean Pillar, we focus on reducing “harmful fats”, such as trans fats and instead using healthful fats in food preparation. For this newsletter, I wanted to highlight the importance of proper use of fats in cooking.
There are two categories of fats, with foods generally containing a combination of the two. For example, butter contains only 61% saturated fat and olive oil can contain up to 12% saturated fat.
Saturated fats are solid at room temperature, highly “saturated” and are generally more stable. Unsaturated fats are liquid at room temperature, include mono and polyunsaturated fats, and are generally less stable.
There are also trans fats, which occur naturally in a few foods, but most of them are artificially made and have been widely criticized for their detrimental effects on health. As they are “officially” being removed from the food supply, I am not going to include them in my analysis.
Understanding Fats & Oils in Cooking
Oils are processed to different levels and this impacts both their quality and how well they hold up when used in cooking. Here is a high-level understanding of the two types of processing for oils.
Unrefined – Cold pressed &/or expeller pressed (minimal heat involved) and contains their natural flavor and color (often including minerals and enzymes as well)
Refined – Process in which “impurities” are removed from the oil (high heat and chemicals involved)
Here is how refining is described by Technochem Inc. “Vegetable and Animal Oils and Fats have impurities such as Moisture, Solids (Insolubles), Gums (Lecithins), Free-Fatty Acids (FFA), Waxes, and Compounds of Sodium, Potassium, Magnesium, Calcium, and other metals. These impurities must be removed to improve the functionality of the oils. Other characteristics of oils (such as Color, odor, and taste) are also considered impurities by modern consumers. These impurities are removed in a series of steps such as degumming (to remove gums), neutralizing (to remove FFA), bleaching (to remove color), deodorizing (to remove odor and taste), and dewaxing or winterization (to remove waxes). More on refining: http://www.technocheminc.com/oil-refining.htm
I think it is important to distinguish that highly refined oils are most often used in high heat cooking (deep-frying) and in ultra-processed foods. The refining process removes all odors, tastes, and any other “impurities” so it does not affect the end product it is being used for. These are commonly referred to as “vegetable” oils, including corn, soy, canola, safflower, etc. We will do another post on the potential health implications of these industrial oils, but that is for another time.
On the other hand, oils that are not refined, such as cold-pressed olive oil, will impart flavor into the foods and does not withstand as high of heat. This is why it is important when cooking with oils and fats, to understand the processing level it has gone through. Which brings me to my next point.
Heating Oils and Fats – Smoke Points
Each oil or fat, depending on its level of refinement, as well as its chemical structure (how saturated it is), will determine how hot it can get before it reaches its “smoke point”.
In the Serious Eats article “Cooking Fats 101: What’s a Smoke Point and Why Does it Matter?”, the smoke point is described like this:
“Heated past its smoke point, that fat starts to break down, releasing free radicals and a substance called acrolein, the chemical that gives burnt foods their acrid flavor and aroma. Think watering eyes, a stinky kitchen, and bitter, scorched food.”
This is where heating methods really matter, and not just for taste, but also for your health!
Below is a table of smoke points for different fats, which can also be found at the end of the Serious Eats article: https://www.seriouseats.com/2014/05/cooking-fats-101-whats-a-smoke-point-and-why-does-it-matter.html
Bottom Line: There is more to know that just what “type” of fat is being used in the food you eat. The processing level and heating methods of oils and fats matter in terms of your health and the quality of the food you are eating. Eat REAL does not support industrial deep-frying using highly refined vegetable oils.
Smoke Point Table
|Type of Fat||Smoke Point||Neutral?*|
|Rice Bran Oil||490°F/260°C||Yes|
|Light/Refined Olive Oil||465°F/240°C||Yes|
|Avocado Oil (Virgin)||375-400°F/190-205°C||No|
|Chicken Fat (Schmaltz)||375°F/190°C||No|
|Extra-Virgin Olive Oil||325-375°F/165-190°C||No|