Cooking Oil Basics
In This Chapter
Every kitchen should be stocked with good-quality cooking oils. The type of oil you use most often should be a healthier variety, such as olive or canola oil, which are better for heart health.
There are many types of oils available in the marketplace today, and selecting the right ones can be confusing. Another factor in choosing the appropriate oil is how you’ll use it in your recipes. In this chapter, we’ll discuss the assortment of fats used in cooking oils and the best ones for the job and for your health.
There are a variety of reasons people use certain oils to cook with. For some it may be about the flavor, for others ease of use; some may have heard a certain oil is heart healthy, as in the case of olive oil. Others may use a certain type or brand of oil because that’s what was used in the household in which they grew up. Whatever the case, it’s important to examine the predominant type of oils in your diet.
Cooking oils are 100 percent fat, provide about 150 calories per tablespoon, and are made up of fatty acids. Each fatty acid is divided into a different category based on their molecular structure. The three categories are saturated; unsaturated, which includes monounsaturated and polyunsaturated; and trans fatty acid—or as it’s commonly referred to, trans fat.
Saturated fat comes from animal products such as dairy, red meat, and poultry. It’s referred to as “bad” fat and is solid at room temperature. Saturated fat means there are hydrogen atoms attached to each carbon atom, thus the atoms are saturated with hydrogen.
Research has shown that saturated fats adversely affect blood lipid levels by increasing your cholesterol and LDL, which can increase your risk of cardiovascular disease and type 2 diabetes. Butter and lard are saturated fats commonly used in cooking.
Monounsaturated and polyunsaturated fats are typically liquid at room temperature. Monounsaturated fats like olive oil will partially solidify when refrigerated, whereas a cold temperature will not affect a polyunsaturated fat like canola oil.
Monounsaturated fats are commonly referred to as heart healthy, and their association with good health came about from findings based on the Seven Countries Study in the 1960s. In this study, the main source of fat found in the people’s diet was olive oil, and the study gave rise to what we now refer to as the Mediterranean diet.
Polyunsaturated fats can also be beneficial to your health, as they posses the same ability to lower cholesterol levels when consumed in moderation. Polyunsaturated fats include omega-3 and omega-6 fatty acids.
The trans fat in our diets is not found in nature, and has been chemically altered in a lab. It’s actually worse for you than saturated fat, and is solid at room temperature. Research from the Harvard School of Public Heath reports that consumption of just 2 percent of calories from trans fat daily equates to a 23 percent increase in the risk of heart disease.
Oils can be costly, and they don’t have a long shelf life once opened. It’s also important to purchase the right volume amount for your household use. It’s not wise to purchase 2 gallons of oil at your local big-box store because it’s cheaper when there are only two of you in your household. A good-quality extra virgin olive oil will only last from 3 months to 2 years unopened in a cool, dark pantry.
Rancid oil is easy to identify by its putrid smell. Many report it has a “paint thinner” smell. When oil becomes rancid, it has been oxidized and aldehydes have formed, causing the varnish- or paintlike smell.
A UC Davis study had subjects taste 22 extra virgin olive oils. Researchers were surprised to learn that 44 percent of the participants preferred the taste of rancid oil opposed to the bitter and pungent flavors in high-quality extra virgin olive oils.
When selecting the primary oil you’ll use for cooking, you need to understand the pros and cons of each type to make an informed choice. You must consider flavor, use, smoke point, and health needs. Most people should have two or three oils on hand in their kitchen.
The Best Monounsaturated Oils for Health
Monounsaturated oils are better for your heart. Consumption of monounsaturated fats helps decrease total cholesterol levels and LDL (bad) cholesterol, and increase HDL (good) cholesterol. They also help lower blood pressure, and the oil is a source of vitamin E. The following list shows the percentage of monounsaturated fats in common cooking oils.
The most commonly used and researched monounsaturated oil is olive oil. Spain produces most olive oil and has about 5 million acres, compared to California at 30,000 acres. Spain takes an average of 6 months to harvest and California has only a 2-month harvest window, according to the North American Olive Oil Association.
Olive oil is a very versatile, heart-healthy oil. It’s made from the pressing of the whole olive, including the pit. It takes about 10 pounds of olives to make 4 cups of oil.
The olive-producing countries have an established set of standards to distinguish between the types of oil, such as extra virgin and refined. The International Olive Oil Council provides one set of guidelines.
In 2008, California passed a law regulating labeling requirements for olive oil. The U.S. government developed standards for grades of olive oil in 2010, but it’s voluntary for producers.
Each type of olive oil is graded and labeled accordingly, based on the characteristic of the oil. Generally, the higher quality the oil, the lower the acidity.
The four enemies of olive oil are time, temperature, oxygen, and light. The amount of time it takes to get the fruit from the tree to the press needs to be minimal. The temperature needs to be held constant, and you must minimize exposure of the oil to heat and cold. Oxygen accelerates the oxidation process and speeds up rancidity, so oils must be tightly bottled. Light can cause damage from UV rays, which is why oils are packaged in tinted bottles to protect them from light.
Olive oils vary greatly in flavor and aroma. There are three key flavor profiles in olive oil: fruity, bitter, and pungent. Fruity is described as buttery, floral, grassy, green, nutty, apple, artichoke, and herbaceous. Bitter is simply bitter tasting, which is a good thing. It typically means there’s a higher antioxidant content in the oil. Pungent oil has a peppery taste, and may slightly burn the back of your throat as you swallow it.
There are several types of olive oil available in the marketplace, including extra virgin, virgin, ordinary virgin, pure, refined, and light-tasting olive oil. Extra virgin makes up about 60 percent of all sales. Let’s take a look at the key types.
U.S. extra virgin olive oil is derived from the first cold pressing of olives. The oil is extracted without added heat. Although the pressing action itself causes friction and thus heat, temperatures are maintained and are not allowed to exceed 85°F. The oil is then collected, filtered, and bottled. Due to this process, extra virgin contains the highest amount of phytochemicals. It also has the strongest flavor with the lowest acidity level and no defects. It has a smoke point of 325 to 375°F. You can cook with extra virgin olive oil, but just don’t exceed the smoke point, as you’ll negate many of the beneficial health properties within the oil.
U.S. olive oil is a blend of refined and virgin oils. It’s flavorless and odorless. The refining method does not alter the chemical structure of the fat. Vitamin E oil can be added back into the product to make up for what was lost during production. It has a smoke point of 465°F.
U.S. olive pomace oil is a blend of olive pomace oil and virgin olive oil. It’s extracted from the leftovers of the fruit and pits along with an added chemical solvent and applied heat. It’s the lowest grade of olive oil you can purchase. The flavor is very different from extra virgin oil and may taste flat. It has a smoke point of 460°F.
When shopping for olive oil, it’s important to identify the following:
Canola oil was originally derived from the rapeseed plant, which has been bred naturally into what we now call the canola plant. Canola oil is extracted from the seeds of the plant. A pod develops from the flower that resembles a pea pod, but is much smaller with about 20 black-brown seeds. The seeds are crushed and the oil is extracted and refined.
Canola oil is a pale golden color with a very neutral taste. It has a smoke point of 400°F. It makes a great choice to use in a salad dressing or emulsification, such as in mayonnaise when you don’t want to impart a flavor. It’s also a good option for baked goods and for use in frying.
Research reported in the British Journal of Nutrition showed that in subjects with high cholesterol levels, the consumption of canola oil instead of flaxseed oil help to lower their LDL cholesterol and total cholesterol levels. Another study published in the Journal of Internal Medicine replaced dietary fat with canola oil and showed a decrease in triglycerides in subjects with high cholesterol levels, along with an overall improvement in serum lipoproteins.
Avocado oil is made from the pulp or flesh of the avocado. The avocado’s flesh can contain 30 percent oil, which is bright green in color due to high levels of chlorophyll and carotenoids.
Chlorophyll is a green plant pigment. It allows a plant to capture light energy and convert it into plant energy through photosynthesis.
Avocado oil extraction is similar to olive oil extraction in that it’s cold pressed without any added solvents; however, water and enzymes can be used.
The mild flavor of avocado oil has been described as having a hint of avocado taste along with a slight butter and mushroom flavor. It can be used in any recipe without imparting any off flavor. Furthermore, it has an extremely high smoke point, between 480 and 500°F, depending on whether it’s cold pressed or refined, which makes it great for frying or using on the grill.
Limited research exists on avocado oil, as it’s a fairly recent newcomer to the marketplace. One study reported in the Journal of Periodontal Disease states that it reduced inflammation in those with periodontal disease. Avocado oil is higher than olive oil in monounsaturated fatty acids, so it makes sense to expect that it offers the same heart-healthy benefits as olive oil.
Safflower oil is extracted from the seeds of a thistlelike annual plant grown in the western Great Plains region in the United States. The plant produces yellow, orange, and red flowers, and it’s allowed to dry in the farmer’s field prior to harvest.
The seeds are then harvested from the flower and are classified as monounsaturated or polyunsaturated. They are sent to processing plants to extract the oil. The monounsaturated oil is used for cooking. The polyunsaturated oil is used in cold applications, because it’s not shelf-stable and must be refrigerated.
Safflower oil is just 1 percent higher in monounsaturated fatty acids than olive oil, and its taste is very mild. This oil can be used in a variety of recipes from baked goods to sautéing and frying, since it has a very high smoke point of 450 to 510°F depending on how refined the product is.
The petals of the safflower blossom can be used as a substitute for saffron, the most expensive spice in the world, which comes from the crocus flower. In the center of each flower are three stigmas (strands) of saffron.
Polyunsaturated fats are essential fats in your diet. A polyunsaturated fatty acid has two or more double bonds in its carbon chain. The chains are classified as omega-3 or omega-6. Both omega-3 and omega-6 are beneficial to your health. Research has shown that replacing saturated fats or highly refined carbohydrates with polyunsaturated fats reduces LDL levels in the blood along with triglycerides, and improves the overall cholesterol profile.
The highest amounts of omega-3s are found in flaxseed. However, walnuts, canola oil, and soybean oil also contain omega-3s.
Flaxseeds come from the flax plant, which grows in cool climates. Flaxseed oil is golden yellow in color and has a nutty flavor. It should not be heated higher than 120°F, so it’s not recommended to cook with. However, it can be great to add to foods after the cooking process.
Flaxseed is approximately 57 percent alpha-linoleic acid (ALA), which is an omega-3. Much research has shown positive effects of diets high in ALA in relation to cardiovascular disease. The Nurses’ Health Study involving 76,763 women revealed that women who consumed less ALA in their diets had a higher risk of sudden cardiac death. Studies have also looked at the protective effects against inflammatory disorders such as rheumatoid arthritis, as well as improved immune function in people with lupus.
A review of the research showed that it also lowered cholesterol levels in postmenopausal women and in people with high cholesterol levels.
Corn, safflower, soybean, walnut, and sunflower oils are high in omega-6 fatty acids (linoleic). Omega-6 is an essential fatty acid. Research has shown omega-6s may help alleviate pain associated with diabetic neuropathy, improve insulin resistance in diabetics, and decrease blood pressure. Other studies examined the role of omega-6 in children with attention deficit hyperactivity disorder (ADHD), which reported a reduction in overall symptoms.
Americans consume a higher ratio of omega-6 to omega-3 in their diets, which can inhibit the benefits of omega-3. Ideally, you need to work toward a 1:1 ratio. Most omega-6s come from processed foods. Let’s take a look at common oils high in omega-6s.
To make soybean oil, the beans are split open, heated, and pressed flat like rolled oats. Next a chemical solvent is used to extract the oil. It has a pale color and neutral flavor, and is a favorite in the food industry as an all-purpose oil. Additionally, the smoke point is 450°F, which makes it an excellent choice for frying. Soybean oil can also be used in any type of recipe, including baked goods and desserts.
Corn oil is extracted from the germ of the seed. It’s expeller pressed and a chemical solvent is applied. It also goes through a degumming and alkali treatment, winterization, and removal of waxes, and then finally steam distillation.
Expeller pressed is a mechanical extraction process that applies pressure until the oil is released from the seeds. This method will render about 65 to 70 percent of the oil.
Corn oil has a pale yellow color and nutty taste with a hint of corn. It has a 450°F smoke point and is a good choice for high-heat applications like frying. Overall, it’s a good neutral cooking oil that can be used in a variety of recipes.
A study published in the Journal of Clinical Lipidology showed a reduction in cholesterol and LDL through the use of corn oil when as compared with extra virgin olive oil. Another study showed that corn oil is high in phytosterols, and researchers believe it’s the phytosterols that aid in cholesterol reduction as opposed to it being an unsaturated fatty acid.
The Negative Impact of Oils on Health
Saturated fats, when consumed in high amounts increase total cholesterol and LDL cholesterol levels in the blood, and overconsumption can increase your risk of heart disease and stroke. It may also increase your risk of type 2 diabetes. The American Heart Association (AMA) recommends no more than 6 percent of your total calories come from saturated fat.
Saturated fats predominantly come from animal sources. These fats are solid at room temperature, such as butter and lard, which are used in cooking. The fatty part around beef steaks, pork, and lamb is also a saturated fat.
Butter is a saturated fat that is made from churning fresh cream or milk. The butterfat is then separated out by the mechanical action. Butter is legally defined as being “made exclusively from milk or cream or both, with or without common salt, and with or without additional coloring matter, and containing not less than 80% by weight of milkfat.”
European-style butters have more fat and less water. Some have additional bacterial cultures added to increase its sweetness and to add tanginess. European butter is churned longer than its American counterpart. The additional churning time decreases the water content, and thus increases the fat content to 84 percent to create a richer profile.
Butter is evaluated by USDA graders, produced in an approved plant, and comes in different grades. U.S. Grade AA is made from sweet fresh cream and has a sweet flavor and smooth, creamy texture. U.S. Grade A is also made from sweet fresh cream and has a smooth texture, but the flavor profile differs slightly from grade AA. The taste may seem a bit flat. U.S. Grade B butter is only sold in a few areas and has an acidic flavor.
Butter can be frozen and will maintain its quality for 2 months. It’s sensitive to odors in the fridge, so be sure to keep it tightly covered. The best way to use butter is to let it sit out 10 to 15 minutes prior to use. Butter can be used in a variety of recipes from sauces to baked goods. Keep in mind that the smoke point of butter is 350°F.
It takes 5 gallons of whole milk to produce about 2 pounds of butter.
Lard is made from pork fat. It has 25 percent of the saturated fat of butter. Lard is known for making crispy piecrust and pastries. Lard creates flakier baked goods because it doesn’t contain any water, and as the fat molecules in lard melt they create little air pockets or layers of flakiness in foods.
Most of the lard found in the marketplace has been hydrogenated to increase shelf life. However, some high-end butcher shops carry lard you can purchase and render down for use in cooking. Good-quality lard has a neutral flavor and a smoke point of 370°F, which makes it a good choice for frying and a favorite of Southern cooks.
There are two types of oil made from the fruit of the palm tree, which grows in tropical regions like Malaysia and Indonesia. Palm kernel oil is made from the kernel or pit inside the fruit, and palm oil is made from the fruit pulp. Palm kernel oil has a negative impact on health and raises cholesterol levels. However, it’s not sold as cooking oil, but is used for making soaps, detergents, and cosmetics.
Palm oil is similar to coconut oil in molecular structure. Palm oil is golden yellow in color, tasteless, and is predominantly used in the food industry. The smoke point of palm oil is 465°F.
Coconut oil is made from the flesh of the coconut by compressing it under high pressure. The mechanical extraction produces some heat, but the temperature doesn’t exceed 120°F. There are no government standards for producing coconut oil. If the product refers to “virgin” oil, it typically refers to the fact that the oil has not been refined or bleached. Coconut oil has a mildly sweet flavor and velvety texture, and is great for sautéing foods as it imparts a subtle sweetness. It has a 350°F smoke point.
Coconut oil is a saturated fat and contains lauric acid, a medium-chain triglyceride. For many decades, coconut oil has been considered a “bad” fat because it is saturated. However, many avid fans of coconut oil tout it as being the cure-all to almost every health-related disease. Unfortunately, sufficient research doesn’t exist to back up these claims.
A review of research in relation to heart disease and coconut oil includes found that people consuming coconut oil did see improvement in HDL, but it also increased their LDL. Another study comparing coconut oil, beef, and palm oil, reported that coconut oil raised their total cholesterol and HDL as compared to beef and palm oil. A large study of Filipino females reported high levels of HDL in those who had the highest intake of coconut oil.
In relation to weight loss, a small pilot study showed a significant reduction in waist circumference. A double-blind clinical trial in 2009 compared soybean oil to coconut oil in obese women and revealed no change in body weight, but did report a reduction in waist circumference in the group consuming coconut oil. Though it looks to be beneficial in relation to HDL, the increase in total cholesterol may negate the benefit. Additional research need to be done on coconut oil and the effects on lipid levels in the body. It’s still a saturated fat and should not be consumed in large amounts in a healthy diet.
Very little trans fats occur in nature. They’re present in small amounts in butterfat, beef, and lamb, but it’s a different molecular structure in nature than what is created in the lab. Trans fats are created when partially hydrogenated oils are chemically altered to add additional hydrogen molecules to make the liquid oil solid. In 2013, the U.S. Food and Drug Administration (FDA) deemed trans fatty acids as unsafe for use in human foods. Researchers began in the 1990s looking at the affect of trans fat in relation to heart disease and stroke. Research showed that trans fats actually increased LDL and lowered HDL.
The food industry liked using trans fats because they had a longer shelf life and were inexpensive. Commercial fryer oil is one example where trans fats were used in the restaurant industry. Additional sources in the diet are baked goods, snack foods, and stick margarines, although most margarine manufacturers have reformulated their products to make them trans fat-free. However, trans fats still exist in products even though the FDA no longer recognizes them as safe and they were removed from the Generally Recognized as Safe (GRAS) listing. The National Academy of Sciences states “trans fatty acids are not essential and provide no known benefit to human health.” However, it’s estimated that 5 to 8 percent of total calories consumed in the American diet are from trans fatty acids.
FDA food labeling law allows food manufacturers the ability to list “0 grams” of trans fat on a food label even though it may actually contain a range of 0 to 0.5 grams. A look at the label will help you identify the trans fat by the words “partially hydrogenated oils.”
The term “shortening” used to refer to lard or margarine, but nowadays shortening means a vegetable-based product. Shortening made prior to 2007 was hydrogenated and contained trans fats. Companies have reformulated their products to remove the trans fat, and these new formulations contain a little less than 1 gram of trans fat per serving.
Nonhydrogenated shortening can also be made from palm oil. It’s semi-solid in texture, contains little water, and is shelf-stable. Vegetable shortening has a neutral flavor and can be used in baked goods such as biscuits and piecrusts. It can also be used to make cake icing. The smoke point of vegetable shortening is 360°F. Vegetable shortening is one of those fats you might have on hand during the holidays for baked goods, but it certainly is not for daily use.
Margarine is made from a variety of monounsaturated, polyunsaturated, and saturated fatty acids from vegetable oils and animal fats. The more solid the form, the more saturated the product. When liquid oils are partially hydrogenated to solidify them, trans fat is formed. When selecting margarine, the spreadable tubs typically contain less trans fat than the sticks. However, it’s important to read the label. The American Heart Association (AHA) recommends people shop for margarine with less than 2 grams of saturated fat per tablespoon.
Margarine was invented in 1869 by French chemist Hippolyte Mege-Mouries. It was made from beef tallow and called oleomargarine. Oleo is Latin for beef fat and margarite is Greek for pearl.
Margarine was intended to be a healthier option to butter when it hit the marketplace. Unfortunately, no one was aware of the trans fat issue and its detrimental effect on health. There are still many varieties available on store shelves, and you can use them in any recipes where you would use butter. Margarine’s smoke point ranges between 302 and 320°F. It’s important to taste the different brands to find a flavor profile you enjoy. Keep in mind that most margarine will still contain some trans fats, so it’s important to read the label.
The Least You Need to Know