Time for an Oil Change?

Joanna Lefebvre

Oil is purified fat of plant or animal origin which is liquid at room temperature. Fats provide a concentrated source of energy for the body, insulate body tissues, and transport fat soluble vitamins through the blood.They provide essential fatty acids—linoleic acid (omega-6) and alpha-linoleic acid (omega-3) and play an important role in nutrition. Fats are also critical components of many recipes and essential to many cooking and food preparation techniques.

Oils: Good and Bad
Fats and oils are made up of basic units called fatty acids.

Saturated Fatty Acids are found predominantly in animal sources such as meat and poultry, whole or reduced-fat milk, and butter. Some vegetable oils like coconut, palm kernel oil, and palm oil are saturated. Saturated fats are usually solid at room temperature.

Monounsaturated Fatty Acids are mostly in vegetable oils such as canola, olive, and peanut oils and are liquid at room temperature.

Polyunsaturated Fatty Acids are found mainly in vegetable oils such as safflower, sunflower, corn, flaxseed, and canola oils. They are liquid or soft at room temperature. Specific polyunsaturated fatty acids, such as linoleic acid and alpha-linoleic acid, are called essential fatty acids. They are necessary for cell structure and making hormones.

Trans Fatty Acids are formed when vegetable oils are processed using a process called hydrogenation into margarine or shortening. Sources of trans fats in the diet include snack foods and baked goods made with "partially hydrogenated vegetable oil" or " vegetable shortening."

Food Prep
Fats and Oils play in important role in food preparation. Fats enhance flavor, add mouth-feel, and tenderize baked products. They also conduct heat and seal in moisture.

In foodservice, fats and oils are used primarily as a frying medium, but also as an ingredient in sauces, dressings and in baking. Depending on the desired flavor of the final product and the amount of heat necessary, oil choices vary. The following is a brief look at the most popular types of oils, along with usage and storage tips.

Refined Oils
Refined oils are extracted from clean oilseed / oil cakes by solvent extraction for further refining. This produces clear oil, free from rancidity and foreign matter. The following are the different types of refined oils.

Almond: Nut oils are best used in cold dishes; heat destroys their delicate flavor.

Avocado: This unusual, light, slightly nutty tasting oil is considered a novelty. Adds a different twist to salads. It is low in saturated fatty acids and is high in polyunsaturated fat.

Canola (rapeseed): A light, goldencolored oil, similar to safflower oil. Extracted from the seeds of a plant in the turnip family. Used in salads and cooking, also used in margarine and blended vegetable oils. It has a mild flavor and aroma. It has the least amount of saturated fat.

Corn oil: Made from the germ of the corn kernel. It is almost tasteless and is excellent for cooking because it can withstand high temperatures without smoking. It is high in polyunsaturated fat and is often used to make margarine, salad dressings and mayonnaise.

Grape Seed: This light, mediumyellow, aromatic oil is a by-product of wine making. It is used in salads and some cooking.

Olive: A monounsaturated oil extracted from tree-ripened olives. Ranging in color from light amber to green and bland to extremely strong in flavor. It is graded according to its degree of acidity and the process used to extract the oil. The four grades include: Extra Virgin,Virgin, Olive Oil.

Peanut: Made from pressed, steam-cooked peanuts. Its bland flavor is good for cooking because it doesn't absorb or transfer flavors. (both refined and unrefined)

Safflower: A clear, almost flavorless oil made from the seeds of safflowers. It's pale yellow with a bland flavor, a favorite for salads because it doesn't solidify when chilled. It is low in saturated fat and high in polyunsaturated fat. (both refined and unrefined)

Sesame: Made from pressed sesame seeds, and available in two varieties: light (made with untoasted sesame) and dark (made with toasted sesame). Light has a nutty flavor and is good for frying. Dark sesame oil has a stronger flavor and should be used in small quantities for flavoring foods. It is high in polyunsaturated fat.

Soybean: Highly refined, very mild and versatile. It accounts for over 80% of all oil used in commercial food production in the U.S. and is a good all-purpose oil.

Sunflower: Made from sunflower seeds, pale yellow with bland flavor that is versatile. (both refined and unrefined)

Vegetable: Made by blending several different refined oils. It is designed to have a mild flavor and a high smoke point. Most vegetable oils are made from soybeans.

Unrefined Oils:
Unrefined cooking oils are processed by coldpressed and expeller-pressed methods and contain a full range of bioactive components that not only have healthful benefits and provide fullbodied flavor but also make the oil more prone to oxidation. Unrefined oils are usually used for salad dressings, marinades, and sauces or light cooking oils.As a general rule, they should not be cooked at high temperatures. (In fact, safflower oil is the only unrefined oil that can become hot enough to reach the temperature necessary for deepfrying.) The strong flavors of unrefined oils can dominate whatever dish or baked good is made with them.

Coconut Oil: A heavy, nearly colorless oil extracted from fresh coconuts. Used primarily in prepared, processed and packaged foods.

Grape Seed: This light, medium-yellow, aromatic oil is a by-product of wine making.

Nut (walnut, hazelnut): The nuts, never blanched, are often toasted for a browner color and better flavor. Used in salad dressings, sauces, baked goods, and for sautèing.

Peanut: Made from pressed, steam-cooked peanuts. It has a bland flavor.

Safflower: an excellent all-purpose oil; however, some oil aficionados find it's flavor too strong for baked goods and salads.

Soybean: Soybeans contain oil that is inefficient to extract in a natural manner; therefore, unrefined expeller-pressed soy oil is rather expensive. Unrefined soy oil has a strong, distinctive flavor and aroma. It has a dark yellow color with a faint green tint.

Sunflower: Made from sunflower seeds. Sunflower oil is pale yellow and has a bland flavor.

Vegetable: An inexpensive and all-purpose blend of oils made from plant sources such as vegetables, nuts and seeds. Most vegetable oils are made from soybeans.