By Anita Bancroft
An assortment of fats and oils are available at your local grocery store to use in all types of cooking applications. Some are better to use than others, especially when heat is involved, so it is necessary to select the right tool for the job. Many oils are suitable for dressings or garnishes, while others are preferable for grilling or stir-frying with higher heat.
It’s important to avoid the smoke point (the temperature a fat or oil begins to smoke), as this can produce toxic compounds and bitter or “off” flavors. Exceeding the smoke point can also destroy valuable nutrients. When selecting your oil, it is important to note that food cooked on the stovetop rarely exceeds 350 degrees. However, this temperature can be exceeded with other cooking techniques such as baking, grilling and frying.
Understanding Types of Fats
Saturated fats typically come from animal products, but some plants are high in this type of fat as well. These fats are solid at room temperature. Saturated fats commonly used in cooking include butter, coconut oil, palm oil and lard. Although saturated fats can add flavor to your dish, they should be consumed in small amounts, as they can raise blood cholesterol levels, which is associated with an increased risk for heart disease. The 2015-2020 Dietary Guidelines for Americans (DGA) recommend limiting saturated fat to less than 10 percent of daily calories (example – less than 200 calories from saturated fat for a diet of 2,000 calories per day, or less than 22 grams/day).
Plant oils, and some animal products, are high in both mono- and poly-unsaturated fats. Unsaturated fats commonly used in cooking include canola, flaxseed, avocado, peanut and olive oil. These fats are associated with a reduced risk for many conditions, including heart disease and stroke. Unsaturated fats lower bad cholesterol, blood pressure and inflammation, while providing nutrients that are essential for building and maintaining cells in the body. The DGA recommend replacing saturated fats with healthier unsaturated fats.
Trans fats are created through hydrogenation, a process that takes oil that is liquid at room temperature (unsaturated) and turns it into a solid fat (saturated). These are commonly found in margarine and shortenings. Like saturated fats, trans fats also have the ability to raise blood cholesterol levels and increase the risk of heart disease. The DGA recommend avoiding trans fats.
Olive oils are a heart healthy choice. They are high in antioxidants and omega-9 fatty acid (Oleic acid). Virgin oils provide the most antioxidants. There is controversy regarding the use of olive oils in cooking. Compared to many other oils, they are actually more stable during heating, making them excellent for all cooking methods.
Storage is essential when it comes to oils. The quickest way to damage stored oil is to expose it to heat, air and light. This causes oil to break down, which leads to a loss of nutrients. Oil should be stored in a cool, dark area and replaced if it has a bitter odor. Some oils (polyunsaturated oils such as flaxseed, grapeseed and walnut) become rancid quicker than others and should be stored in the refrigerator to extend their shelf life.
Anita Bancroft is a senior in the Department of Food Science and Nutrition.