Seeds, beans, fruits and nuts are essential foods.
They are parts of plants and contain a concentrated form of energy called fat.
Their chemical composition and ease of removal from the plant, makes fat the perfect substance to prepare and flavor food.
Oils, whether extracted, refined or unfiltered, are equal with respect to caloric value. They all differ in their pigments, aromatic molecules and fatty acid content. Those oils that retain the phytomolecules and fatty acid profile of the source plant are healthier oils.
All oils are best preserved in an airtight, refrigerated bottle because they are vulnerable to oxidative attack from the air just as when they are exposed to aggressive free radicals in the body.
All oils are not alike. The quality of the fruit, nut or seed is one component of a good oil, the quality of the extraction is another. The best oils come from methods that retains the original plant compounds and maintains the fatty acid profile of the fruit, seed or nut it is extracted from. That eliminates all users of chemical solvents, enzymes and high temperature.
Stone pressing is the traditional method of extracting oil from olives. Stone pressing produces no heat. This method is still employed by high-quality, expensive, olive oil manufacturers.
Unfiltered, stone pressed olive oil has small bits of olive in it. These olive fragments retain the natural antioxidants and olive polyphenols (3, 4-dihydroxyphenyl ethanol, hydroxytyrosol and tyrosol) contained in the whole olive.
Extra-virgin olive oil offers the healthy, beneficial effects of the whole fruit of the olive.
Mediterranean countries including Italy, Greece and Spain have less incidence of heart disease despite their relatively high-fat diet. Much of their fat is derived from olive oil, which may account for their cardio-health. Their proper use of different types of olive oils to meet different culinary conditions combined with daily walking makes these active Europeans healthier than sedentary Americans who are addicted to unhealthy fats.
Unhealthy fats are the single greatest contributor to a poor diet.
The substitution of olive oil as much as possible greatly reduces this danger. In addition to an improved lipid profile, olive oil tastes amazing.
This program recommends olive oil as a daily source of fat to the exclusion of all others. Other oils recommended include flaxseed, grapeseed, primrose and macadamia oils.
Stone pressed oil, the traditional method of extracting oil from an olive, does not tolerate high temperatures.
Cooking therefore requires other forms of olive oil; the yellower, more refined virgin olive oil and the still more refined, olive oil.
Unfiltered, cold-pressed olive oils are best used raw and uncooked but can be used at low or moderate temperatures (light sautéing).
Extraction of an oil from its whole form (fruit, nut or seed) is a process with many variables. It begins with a pressing. Hydraulic pressing is used to produce avocado, olive and walnut oils. The oil is squeezed out means of a weight applied by a crank. This is the traditional way of extracting olive oil.
Oils that are pressed and limited to only this faction of exudate are known as cold-pressed oils.
Stone pressed oils are considered cold pressed oils. Since there is no legal standard that oil manufacturers have to adhere to, the term on labels is meaningless. Mechanical pressing or expeller pressing involves machines that use stainless steel presses.
Stainless steel presses produce friction and heat. The higher the pressure applied, the more the heat that is generated. High pressures can raise the temperature of the oil to to over 300°F. Cold-pressed oils on the other hand are never heated above 120°F.
Ten percent of an oil still remains in the residual pulp after making cold-pressed oil. Solvent extraction removes the remaining oil from this pulpy leftover. During this process, the raw pulp is exposed to hexane, a volatile carcinogenic solvent. The oil/hexane mixture is then heated to a high temperature of 230 F in order to remove the hexane. The antioxidant properties and natural preservative of the oil are lost during this process and preservative such as BHT and BHA have to be added to prevent rancidity.
A combination of mechanical and solvent extraction is the most common method used to manufacture inexpensive olive oil. Cheap olive oil is still a better alternative to polyunsaturated oils.
Filtered oil is made from raw seeds, nuts or fruit that has been crushed at high temperatures. The oil is squeezed out in a high pressures system that heats, alters and refines the oil. When pressing is completed, the oil paste is further altered by the addition of a chemical solvent. The carcinogen hexane is the solvent added to dissolve the pulp residue.
The refining of oils involves high temperatures, deodorants and preservatives. The resulting oil lacks the color, aroma, taste, and health benefits of stone pressed, unfiltered olive oil but because it has few phytopigments, its smoke point is higher and can therefore be heated to higher temperatures.
Refined oil is exposed to high temperatures, which makes it more susceptible to chemical breakdown and therefore requires the addition of preservatives to prevent rancidity.
Oil that tolerates high temperatures is correlated with the smoking point of an oil. The lower the temperature or smoke point, the earlier the oil will begin to decompose and smoke. The smoke contains the impurities in the oil that are burning. In the case of extra-virgin olive oil, it is the phytopigments and pieces of the fruit that are burning. Well-filtered oils have higher smoke points since their impurities have already been removed.
Highly filtered oils are thus more desirable for frying because frying requires very hot oil. The food that is cooked in hot oil immediately produces a layer of denatured proteins and altered sugars to prevent the food from absorbing too much of the oil.
Unrefined oils, aside from being more nutritious, are more unstable and have shorter, shelf lives. The fatty acids they contain combine with oxygen to create free radicals, which then attack other fatty acids, converting the healthy oils to unhealthy rancid ones. Unrefined oils should never be used when cooking at temperatures of 320 F. Higher than this accelerates free radical formation and promotes rancidity.
The three fuel nutrients (carbohydrates, fats and protein) depend on an exact interplay between a series of enzymes. Any alteration in any of the enzymes leads to dysfunction.
Enzymes operate on the same receptor-ligand binding mechanism that powers Nature. Dysfunction in receptor binding initiates disease. It is the single most consistent manifestation of disease.
Nutritional chronic disease develops when the metabolism of a nutrient is altered. Diabetes is a disorder in carbohydrate metabolism while atherosclerosis or hyperlipidemia represents a malfunction in fat metabolism.
Fats are essential to membranes, where they are found embedded in the form of lipids or in conjunction with proteins as lipoproteins. Membranes make up the cell’s frontier. Dispersed across this frontier are lipids that are part of receptors, which function to interact with molecules (ligands). Receptors act as traffic cops in directing cell activities.
Fat function in the body includes their use as a starting point for the production of other compounds such as inflammatory mediators, cholesterol carriers and steroid hormones.
Alteration in a lipid’s binding capability, an altered ratio of fatty acids and improper metabolism are responsible for initiating illness.
Polyunsaturated fatty acids, when subjected to oxidation, form lipid peroxide compounds. Lipid peroxides are powerful free radicals that damage cell structures by attacking the structures that contain fatty acids. compounds formed.
Dietary fat contains mixtures of saturated, monounsaturated and polyunsaturated fatty acids. Saturated fats and certain unsaturated fatty acids must be minimized because they are harmful to health. Most fat is obtained from commercial oils, which are categorized according to the predominant fatty acid they contain. Olive and canola are the two main monounsaturated oils, which is the fatty acid least harmful to the body.
The seeds, beans, nuts, kernels and fruits of plants contain enormous amounts of energy in the form of fat. Except for olives, this fat is stored in the endosperm or inner fruit of the seed. These fuel stores are the sole energy source for the developing embryo and when pressed and extracted provide the oils that are used to prepare and flavor food.
The properties that determine the use for a given oil are based on the its physical properties. Smoke point of is a measure of its thermal stability when heated and is the temperature that an oil can be heated to before it begins to smoke. Its discoloration is a visual indication of the molecular damage done to the oil. Smoke Point is related to the free fatty acid content of the oil. The more free fatty acids, the lower the smoke point. A high smoke point is desirable for cooking.
Flash point is the temperature that causes the creation of volatile products. These volatile components are probably carcinogenic. The more free fatty acids the oil contains, the lower its flash point.
Free fatty acids are formed when long chained fatty acids are attacked by free radicals. Fragments are cleaved off the chain creating many small free fatty acids with low molecular weights. Free fatty acids lower the smoke and flash points of an oil. This makes the oil unhealthier over time. Oils that are subjected to extended use, have an increase in their free fatty acid content, resulting in a lower of the smoke, flash, and fire points.
Cooking oils should not be reused too often.
Saturated oils are associated with an increase risk of heart disease. Coconut (cocus nucifera) oil or for lack of a better term, coconut fat, (it is a solid at room temperature due to the high degree of saturation) is ninety-two percent saturated and is a common ingredient in commercially prepared cookies and baked goods.
Both coconut oil, and palm kernel (seed) oil are edible plant oils derived from the fruits of palm trees. Palm oil is extracted from the pulp of the oil palm fruit and is a semi -solid at toom temperature. It is less saturated and less refined than palm kernel oil and coconut oil.
Like all vegetable oils, palm oil does not contain cholesterol. Cholesterol is found only in animal fats.
Palm oils’ saturation increases both the low or lousy cholsterol as well as the high or healthy version.
Palm (Elaesis guineensis) contains a very concentrated source of energy in the pulpy fruit of the plant. Palm oil is fifty-one percent saturated fat and was favored by the Industry in the 1960s and the 70s because baked products that were made with them had long shelf lives. Health concerns and a better understanding of fat metabolism has limited its use, replaced with partially hydrogenated oils.
Polyunsaturated oils, which were previously believed to be safe, have now been linked with the production of free radicals and improper lipid metabolism.
Improper lipid metabolism is linked to atherosclerosis and free radical attacks are associated with cancer formation.
Palmitic and stearic acids are the most common long chain, fatty acids found in saturated fat. These fatty acids contain 18 carbons and are frequently found in animal fat, milk, eggs, ice cream and butter. Certain plants including coconut and palm also are high in saturated fat. Cholesterol, a 27 carbon-ring structure is only found in animal fat.
Palm oil is an agricultural commodity that threatens the rainforests of the world. Palm oil is used in over half the consumer goods purchased by Americans.c They range in form from lipstick to body lotion, from packaged foods to biofuels.
Over 80% percent of palm oil is grown in Indonesia and Malaysia.. Palm oil production damages the environment by deforestation, endangering species and increasing greenhouse gaess.
Pollution is exacerbated when rainforests are destroyed. Greenpeace claims that deforestation, caused by making way for oil palm plantations, is far more damaging to the climate than the benefits gained by switching to biofuel.
Despite its harm to health, demand for palm oil has tripled in the last five years. This is due to its use as a replacement for fossil fuels. Demand has pushed palm oil cultivation into the rainforests and made this plant one of the key causes of rainforest destruction. The Indonesian rainforest is being decimated by corporations and consumer demand. Their need for cheap vegetable oil and biofuel has fueled this destruction.
Agribusiness companies like Cargill own many palm oil plantations in Southeast Asia, which makes them a powerful force in rainforest destruction.
Cargil is the biggest palm oil plantation owner in the world. And they and their subsidiaries place palm oil in as many food products they can. Over a hundred General Mills products alone contain it. The list includes Cheerios, Betty Crocker, Stovetop Hamburger Helper and Bisquick
Safflower (Carthamus tinctorius) oil is the most unsaturated of the oils and is well suited for cold temperatures. Safflower oil is used in salad dressings and margarine that are kept refrigerated.
There was an initial flurry of interest in safflower oil, as it was believed that it improved health. This view is now in decline. Safflower oil contains seventy-five percent linoleic acid, sixteen percent oleic acid and six and a half percent saturated fat. Like all commercial polyunsaturated cooking oils safflower is partially hydrogenated to reduce its susceptibility to oxidation and decrease it’s rate of rancidity.
Soybean oil extracted from the soy pea (Glycine max) contains nine percent linolenic acid that due to its three double bonds becomes subject to chemical attack and rancidity.
Soybean oil contains fifty-five percent linoleic acid, twenty-five percent oleic acid and fifteen percent saturated fat.
Soybean oil is used for cooking and in salads.
Both safflower and soybean oils have high smoke points and are therefore used in deep fat frying.
Corn oil (Zea mays) is a polyunsaturated vegetable oil. Corn oil contains natural antioxidants that provide protection against oxidation reactions.
Corn oil has high levels of linoleic acid but lack alpha-linolenic acid, the essential omega-3 fatty acids. Corn oil smokes when heated to a high temperature.
The olive (Olea europea) was first cultivated in Crete 5000 years ago and ever since, olive and its oil have been a nutritional staple to flavor and prepare food. Olive oil is the only oil obtained from the fruit of the plant rather than its seed. Oils that are derived from the seeds of the plant, require extensive refining. This process makes them non-toxic and safe but also removes its important phytochemicals.
Some of these compounds protect the developing plant embryo from free radical attack. The olive in particular is high in tocopherols (vitamin E) and polyphenols. These compounds also protect the extracted oil from oxidation after processing.
Olives and its oil are a nutritional treasure chest filled with a library of important phytochemicals. The full spectrum of compounds are found in the whole fruit and unfiltered oil. Refining removes them.
Olive oil is the primary source of fat in the Mediterranean diet and is high in high monounsaturated fat and rich in antioxidants. Olive oil has a long shelf life and like all oils contains 14 grams of fat per tablespoon, which provides 120 calories. Since olive oil provides such a strong and distinct flavor, less is needed to flavor food.
The chemical characteristics of olive oil is the consequence of the phytochemicals left in the oil. The more that remain of the whole fruit, the better tasting and healthier the oil.
Unfiltered, stone pressed olive oil has small bits of olive in it. These olive fragments retain the natural antioxidants and olive polyphenols (3, 4-dihydroxyphenyl ethanol, hydroxytyrosol and tyrosol) contained in the whole olive.
Olive oil is recommended as a substitute for all other fats whenever possible.
Olive oil extraction crushes the fruit of the olive to obtain its oil. The freshness and chemical uniqueness of olive oil is maintained only when it is milled and pressed within twenty-four hours of being picked. Consumers are unaware of these practices and can’t determine if those conditions are met. Buying from quality olive oil manufacturers is the only way to ensure that freshness.oils Sediment deposited at the bottom of the container is a sign of good, unfiltered olive oil.
The first pressing of the olives is the highest in quality. The quicker the picked olive’s oil is extracted, the healthier the oil will be. Less oxidation produces better oil.
Olives are first washed with water to remove any impurities on its skin and then crushed to a paste. This begins the extraction process. The traditional cold squeezing breaks the olive’s pulp by employing two turning granite wheels. Since there is no heat involved it is known as cold pressing.
The first cold pressing produces the most flavorful and healthiest oils. Warm squeezing is the modern method. The pulp is heated and then centrifuged to separate the oil from the solid residue. Commercial centrifugation generates heat as it removes water from the olive dough. This heat alters the phytochemical properties of the oil and make it more susceptible to free radical attack.
Refrigeration does not alter or damage extra virgin olive oil but it does cause fat droplets to coalesce. Solid block formation during refrigeration is an indication of a poor olive oil.
Olive oil is bottled in dark colored glass bottles and tin cans to protect it from the sun’s ray and oxidation. Large containers of olive oil should be stored in a cool, dark room. Cruets containing olive oil should be closed and constantly refilled to minimize the amount of space that oxygen can occupy. This prevents the oil’s oxidation.
Classification of Olive Oils
The classification of olive oil is based on the amount of acidic fats in the oil and varies based on climate, pressing technique, and the length of time between picking and pressing. Acidity is a reflection of the amount of oleic acid in the oil, which is also affected by the quality of the olives and the manner in which they are harvested. The more acidic the oil, the more it can withstand high temperatures.
A good quality olive oil retains much of the flavor of the fruit of the olive. The best ones are stone pressed and unfiltered. The more refined the oil, the more the oil loses flavor and taste.
The more fruity and aromatic the oil, the greater is its nutritional value.
1. Extra Virgin Olive Oil has an acidity level of 1% or less. Acidity is a function of oleic acid concentration. Extra Virgin is the healthiest and tastiest form of olive oil. It is not a good oil to cook with since its smoke point is around 370 degrees.
2. Soprafino Virgin Olive Oil is 2% acidic. 400 degree SP
3. Fino Virgin Olive Oil is produced by industrial refining and is even more acidic with up to 3 % acid and a SP of 420
4. Virgin Olive oil is a light colored oil that contains 4% acid.
Sansa (Pomace) is highly refined oil that is obtained by solvents used to dissolve the pulpy residue (sansa). The sansa still contains oil but requires more extensive processes to extract it. The resulting oil contains more than 4% acidic components and many chemical imperfections. Since the refined oil is devoid of flavor and taste, it is often blended with Extra Virgin oil to lend flavor to the oil and makes a good choice for high temperature cooking.
The Food and Drug Administration now permits food manufacturers to claim that olive oil can reduce the risk of coronary heart disease due to its monounsaturated fat content.
Extra-virgin olive oil is the least acidic of the olive oils. The best extra-virgin olive oil contains less that 1% free acid. Acidity lends a sensation of sourness to the oil. The less free fatty acids in the oil, the better the tasting oil. Extra-virgin olive oil is much less acidic than virgin olive oil. The more an oil is refined, the higher its oleic acid content.
Differences in extra virgin batches are due to the region and climate where the olives were cultivated. The type of olive and the manner in which the olives are harvested provide other flavor differences.
Virgin olive oil is the most common olive oil found in supermarkets. They are good oils for light cooking. Virgin olive oil lacks the flavor, aroma and phytopigments of extra virgin but is more heat resistant.
Extra light and light olive oils are more refined, have less taste and phytochemicals but still retains the calories of the more pigmented extra virgin. These light olive oils are even more heat resistant and make a better choice for cooking.
Extra virgin olive oil is the preferred type since it contains all the unaltered phytochemicals, nutrients, flavors and aromas of the whole olive. These compounds give olive oil its distinctive fruity flavor and provides important health benefits.
The health benefits attributed to olive oil include an improved lipid profile and lower cholesterol levels. It is also thought to prevent cancer though its library of olive polyphenols, flavonoids and tocopherols..
Canola oil (short for Canadian Oil) is extracted from the Canadian rapeseed, a biotech creation produced through genetic engineering and seed splitting. The canola seed was bred to remove the undesirable compounds of rapeseeds.
Oils from rapeseed that contains higher erucic acid levels have industrial uses such as lubricants and rubber additives. They are also used in the manufacture of nylon, diesel fuels and pesticides.
Rape is a plant in the mustard family. Its oil is monounsaturated and contains almost 60 percent monounsaturated fatty acids (compared to about 70 percent in olive oil). Unfortunately, two-thirds of its monounsaturated fatty acids are erucic acid, a monounsaturated fatty acid associated with causing fibrotic lesions of the heart.
In the late 1970s, Canadian plant breeders created a variety of rapeseed that produced a monounsaturated oil low in erucic acid. In 1985, after the Canadian government lobby spent over fifty million dollar, the U.S. Department of Agriculture granted canola oil GRAS (Generally Recognized as Safe) status for use in foods.
When introduced, Canola oil was marketed to health-conscious consumers wanting to rid their diet of saturated fat.
Canola use in the kitchen is better than the other non-olive alternatives. Canola use in commercial food however is a health hazard since canola oil is more likely to be converted into trans fat during processing.
Canola resembles olive oil in composition. Canola oil contains 62% monounsaturated and only 6% saturated fats. The seed is high in linolenic acid (omega-3s), much of which is destroyed by the heat and solvents used to extract the oil.
The seeds from the rape plant (brassica napus) contain an unusually long-chain fatty acid, erucic acid. Erucic acid is toxic to the heart and is the reason for the modification of rapeseed.
Canola oil manufacturers minimize the amount of erucic acid in the final product by high temperature extraction and excessive refinement. Cold-pressed, unrefined Canola oil is the preferred type of Canola. It is found primarily in health food stores and is very expensive.
Canola oil is a cheap alternative to the healthier virgin olive and grape seed oils. Canola oil is capable of withstanding high temperatures, which make them good for cooking.
Canola oil contains a high percentage of monounsaturated fatty acids. The seeds are also high in omega-3 fatty acids. These acids are unfortunately transformed into trans-fats during the deodorization process.
Canola oil is often used in processed food. Canola oil is hardened by the hydrogenation process and can contain up to fifty percent trans-fatty acids. The amount of trans fat in processed canola oil varies. Canola oil is mostly regarded as healthy oil with a smoke point above 400 degrees.
Canola oil has not lasted the test of time and is only recommended for high temperature cooking where the dangers of using polyunsaturated oils are very high. The cold-pressed unfiltered form is healthier and more expensive.
Flaxseed and linseed oils are derived from the seeds of the flax plant (linum usitatissimum). The thin fibers from the stem are woven into linen and also used to make napkins and parchment paper. Linseed oil is an industrial oil, derived from commercial pressing and extraction of flax seeds, is used to make linoleum .
The variety of the plants are different for human consumption but all contain high proportions of fatty acids.
Flaxseed is The seed are a rich source of fat and omega-3 fats.
Quality flaxseed oil provides omega-3 fatty acids and the less desirable linoleic or omega-6. While omega-6 oils are essential (the body can’t synthesize it), it is not a desirable one.
Flax seeds are small ovals that are rich in solid fat.
They are added to meal, cereals and breads for their high concentration of fat. In the plant, the fat is is used to support the developing embryo.
Typical flaxseed oil is highest in the omega-3 fatty acid alpha-linolenic acid (ALA). Up to 60% of the total fatty acids are ALA. Yellow flax seeds, as opposed to the more common brown seeds, are lower in ALA. They are used to make Solin, an oil developed for cooking.
Flaxseed oil should never be used for cooking. Flaxseed oil turns rancid easily. The use of flax seeds themselves are preferred to the use of its oil because of its ease of chemical breakdown.
Flaxseeds contain compounds that lower the level of estrogen in post-menopausal women, which may protect them from developing breast cancer. These compounds are known as lignans. Lignans are fiber-like compounds that interact with steroid hormones and their receptors.The naturally occurring phytoestrogens molecule or lignan is believed responsible for the protective effect on health.
Lignans are converted by digestive bacteria into estrogen-like substances called enterodiol and enterolactone. These compounds produce anti-tumor effects via their occupation of estrogen receptors thereby preventing estrogen from exerting its harmful effects in post-menopausal women.
Lignans are also believed to lower the level of two estrogens (estrone sulfate and estradiol) in post-menopausal women by inhibiting estrogen production. Lignans also interfere with testosterone activity in men and is believed to slow the growth of prostate cells.
Flaxseed is high in lignan. Flaxseed oil has none.
Flaxseed oil lacks lignans, but some processors add them to their oil.
Manufacturers have responded to the need for healthy fats in the diet. New healthy oils for cooking are made from avocados, pumpkin seeds, sesame seeds, grapeseeds, macadamia nuts, peanuts and walnuts. They are in addition to olive, canola, soy, sunflower and corn that stock most supermarket shelves. These boutique oils provide unique flavor and contain a different library phytochemicals.
Peanut oil from (Arachis hypogaea) is a premium cooking oil. Peanut oil can withstand high temperatures without smoking. Its smoke point is above 400 degrees. Peanut oil does not absorb and retain odors.
Macadamia nuts diet increase the HDL or good cholesterol level and lowers the LDL or bad cholesterol.
Macadamia nut oil is a good source of palmitoleic acid (an omega-7 fatty acid). Palmitoleic acid may confer some beneficial effect on the heart.
Macadamia oil is extracted in an oxygen and light-free environment. It is processed in a low temperature environment to protect the natural phytochemicals, antioxidants and preservative of the nut. There are no chemical solvents used in this process and so the phytochemicals are retained. It is an expensive oil with a smoke point of 385 degrees.
Grapeseed oil is pressed from the seeds of grapes (vitis vinifera).
Because it has a high smoke point (420 degrees), it is useful in all types of cooking including frying and baking. It provide a nutty flavor to food and is often used in salads dressings. Grapeseed oil contains antioxidants and vitamins and thought to lower cholesterol and raise HDL levels. Grapeseed oil is often used in the cosmetic industry as a moisturizer and wrinkle remover.
Walnuts are high in fatty acids and in particular, omega-3 fatty acids. In fact, walnut is the only nut permitted by the Food and Drug Administration to include a health claim on its label indicating that walnuts reduce the risk of coronary artery disease.
Despite it FDA approval, walnut is not the healthiest nut since absolute amount of omega-3s is not the only criteria to judge an oil. FDA approval is misleading si