Margarine
| Infobox on Margarine | |
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| Example of Margarine |  |
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| Stowage factor (in m3/t) | - |
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| Risk factors | See text |
Margarine
Description
Margarine is a foodstuff used for spreading, baking, and cooking. It was originally created as a substitute for butter in the 1800s. Margarine is made mainly of hydrogenated or refined plant oils and water. While butter is made from fat from milk, margarine is made from plant oils and may also contain milk. In some locales it is colloquially referred to as "oleo", short for oleomargarine.
Margarine, like butter, consists of a water-in-fat emulsion, with tiny droplets of water dispersed uniformly throughout a fat phase which is in a stable crystalline form. Margarine has a minimum fat content of 80%, the same as butter, but unlike butter reduced-fat varieties of margarine can also be labelled as margarine.
Margarine can be used both for spreading or for baking and cooking. It is also commonly used as an ingredient in other food products, such as pastries and cookies, for its wide range of functionalities.
The basic method of making margarine today consists of emulsifying a blend of hydrogenated vegetable oils with skimmed milk, chilling the mixture to solidify it and working it to improve the texture. Vegetable and animal fats are similar compounds with different melting points. Those fats that are liquid at room temperature are generally known as oils. The melting points are related to the presence of carbon-carbon double bonds in the Fatty Acids components. Higher number of double bonds give lower melting points.
Partial hydrogenation of a typical plant oil to a typical component of margarine. Most of the C=C double bonds are removed in this process, which elevates the melting point of the product.
Commonly, the natural oils are hydrogenated by passing hydrogen through the oil in the presence of a nickel catalyst, under controlled conditions. The addition of hydrogen to the unsaturated bonds (alkenic double C=C bonds) results in saturated C-C bonds, effectively increasing the melting point of the oil and thus "hardening" it. This is due to the increase in van der Waals' forces between the saturated molecules compared with the unsaturated molecules. However, as there are possible health benefits in limiting the amount of saturated fats in the human diet, the process is controlled so that only enough of the bonds are hydrogenated to give the required texture. Margarines made in this way are said to contain hydrogenated fat. This method is used today for some margarines although the process has been developed and sometimes other metal catalysts are used such as palladium. If hydrogenation is incomplete (partial hardening), the relatively high temperatures used in the hydrogenation process tend to flip some of the carbon-carbon double bonds into the "trans" form. If these particular bonds aren't hydrogenated during the process, they will still be present in the final margarine in molecules of trans fats, the consumption of which has been shown to be a risk factor for cardiovascular disease. For this reason, partially hardened fats are used less and less in the margarine industry. Some tropical oils, such as Palm Oil and Coconut Oil, are naturally semi solid and do not require hydrogenation.
Modern margarines can be made from any of a wide variety of animal or vegetable fats, mixed with skim milk, salt, and emulsifiers. Margarines and vegetable fat spreads found in the market can range from 10 to 90% fat. Depending on its final fat content and its purpose (spreading, cooking or baking), the level of water and the vegetable oils used will slightly vary. The oil is pressed from seeds and refined. It is then blended with solid fat. If no solid fats are added to the vegetable oils, the latter undergo a full or partial hydrogenation process to solidify them. The resulting blend is mixed with water, Citric Acid, carotenoids, vitamins and milk powder. Emulsifiers such as lecithin help disperse the water phase evenly throughout the oil, and salt and preservatives are also commonly added. This oil and water emulsion is then heated, blended, and cooled. The softer tub margarines are made with less hydrogenated, more liquid, oils than block margarines.
Three types of margarine are common:
- Soft vegetable fat spreads, high in mono- or polyunsaturated fats, which are made from safflower, sunflower, soybean, cottonseed, rapeseed, or Olive Oil.
- Margarines in bottle to cook or top dishes
- Hard, generally uncoloured margarine for cooking or baking.
Blending with butter
Many popular table spreads sold today are blends of margarine and butter or other milk products. Blending, which is used to improve the taste of margarine, was long illegal in countries such as the United States and Australia. Under European Union directives, a margarine product cannot be called "butter", even if most of it consists of natural butter. In some European countries butter-based table spreads and margarine products are marketed as "butter mixtures".
Butter mixtures now make up a significant portion of the table spread market. The brand "I Can't Believe It's Not Butter!" spawned a variety of similarly named spreads that can now be found on supermarket shelves all over the world, with names like "Beautifully Butterfully", "Butterlicious", "Utterly Butterly", and "You'd Butter Believe It". These butter mixtures avoid the restrictions on labelling, with marketing techniques that imply a strong similarity to real butter. Such marketable names present the product to consumers differently from the required product labels that call margarine "partially hydrogenated vegetable oil".
Nutrition
Discussions concerning the nutritional value of margarines and spreads revolve around two aspects — the total amount of fat, and the types of fat (saturated fat, trans fat). Usually, a comparison between margarine and butter is included in this context as well.
Mount of fat
The roles of butter and traditional margarine (80% fat) are similar with respect to their energy content, but low-fat margarines and spreads are also widely available.
Saturated fat
Saturated fatty acids have not been conclusively linked to elevated blood cholesterol levels. Replacing saturated and trans unsaturated fats with unhydrogenated monounsaturated and polyunsaturated fats is more effective in preventing coronary heart disease in women than reducing overall fat intake.
Vegetable fats can contain anything between 7% and 86% saturated fatty acids. Liquid oils (canola oil, Sunflower Oil) tend to be on the low end, while tropical oils (Coconut Oil, palm kernel oil) and fully hardened (hydrogenated) oils are at the high end of the scale. A margarine blend is a mixture of both types of components. Generally, firmer margarines contain more saturated fat.
Typical soft tub margarine contains 10% to 20% of saturated fat. Regular butterfat contains 52 to 65% saturated fats.
Unsaturated fat
Consumption of unsaturated Fatty Acids has been found to decrease LDL cholesterol levels and increase HDL cholesterol levels in the blood, thus reducing the risk of contracting cardiovascular diseases.
There are two types of unsaturated oils: mono- and poly-unsaturated fats both of which are recognized as beneficial to health in contrast to saturated fats. Some widely grown vegetable oils, such as rapeseed (and its variant canola), sunflower, safflower, and olive oils contain high amounts of unsaturated fats. During the manufacture of margarine, some of the unsaturated fats may be converted into hydrogenated fats or trans fats in order to give them a higher melting point so that they are solid at room temperatures.
Omega-3 fatty acids
Omega-3 fatty acids are a family of polyunsaturated fatty acids, which have been found especially good for health. This is one of the two Essential fatty acids, so called because humans cannot manufacture it and must get it from food. Omega-3 fatty acids are mostly obtained from oily fish caught in high-latitude waters. They are comparatively uncommon in vegetable sources, including margarine. However, one type of Omega-3 fatty acid, alpha-Linolenic acid (ALA) can be found in some vegetable oils. Flax oil contains 30-50% of ALA, and is becoming a popular dietary supplement to rival fish oils; both are often added to premium margarines. An ancient oil plant, camelina sativa, has recently gained popularity because of its high Omega-3 content (30-45%), and it has been added to some margarines. Hemp oil contains about 20% ALA. Small amounts of ALA are found in vegetable oils such as soybean oil (7%), rapeseed oil (7%) and wheat germ oil (5%).
Omega-6 fatty acids
Omega-6 fatty acids are also important for health. They include the essential fatty acid linoleic acid (LA), which is abundant in vegetable oils grown in temperate climates. Some, such as hemp (60%) and the common margarine oils corn (60%), cottonseed (50%) and sunflower (50%), have large amounts, but most temperate Oil Seeds have over 10% LA. Margarine is very high in omega-6 fatty acids. Modern Western diets are frequently quite high in Omega-6 but very deficient in Omega-3. The omega-6 to omega-3 ratio is typically 5:1 to 10:1. Large amounts of omega-6 decreases the effect of omega-3. Therefore it is recommended that the ratio in the diet should be less than 4:1, although optimal ratio may be closer to 1:1.
Trans fat
Unlike other dietary fats, trans fatty acids are not essential and provide no known benefit to human health. There is a positive linear trend between trans fatty acid intake and LDL cholesterol concentration, and therefore increased risk of coronary heart disease, by raising levels of LDL cholesterol and lowering levels of HDL cholesterol.
Several large studies have indicated a link between consumption of high amounts of trans fat and coronary heart disease, and possibly some other diseases, prompting a number of government health agencies across the world to recommend that the intake of trans-fats be minimized.
In the US, partial hydrogenation is common as a result of preference for homegrown oils. However, since the mid-1990s, many countries around the world have started to move away from using partially hydrogenated oils. This led to the production of new margarine varieties that contain less or no trans fat.
Cholesterols
Excessive cholesterol is a health risk because fatty deposits gradually clog the arteries. This will cause blood flow to the brain, heart, kidneys and other parts of the body to become less efficient. Cholesterol, though needed metabolically, is not essential in the diet. The human body makes cholesterol in the liver, producing about 1g of cholesterol each day or 80% of the needed total body cholesterol. The remaining 20% comes directly from food intake.
Therefore overall intake of cholesterol as food has less effect on blood cholesterol levels than the type of fat eaten. However, some individuals are more responsive to dietary cholesterol than others. The U.S. Food and Drug Administration states that healthy people should not consume more than 300 mg of cholesterol each day.
Most margarines are vegetable-based and thus contain no cholesterol. 100 grams of butter contains 178 mg of cholesterol.
Shipment / Storage / Risk factors
Margarine is now seen as a product in its own right rather than as a butter substitute. A significant factor is public awareness of the role of dietary fats in heart disease. A wide variety of different types of margarine are marketed today, differing in raw materials, proportion of polyunsaturated fats, spreading properties, packaging etc. Margarine is rarely subject to microbial spoilage, but m,ay become rancid due to oxidation. Margarine can pick up taints if improperly stored.
The P.S.L. (Potential Storage Life) of margarine is 3 months at 5°C.