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The production of margarine involves various processes, with the aid of a variety of chemicals or materials. This processes are very similar to the ones used in plastic production.
The process of producing margarine goes through a number of stages (1):
Storage of oilseeds
Before processing, the first step in the production of margarine (or vegetable oil) is storage. Oilseeds are dried to achieve less than 10% moisture and then stored, sometimes for long periods of time.
The stored oilseeds, depending on the conditions, may develop mold infection and mycotoxin contamination. They also may be infested by insects and rodents.
To prevent the oilseeds from spoilage, they must be kept under strict hygienic conditions, with the right temperature, aeration and humidity level. To prevent insect or pest infestations, oilseeds are treated with toxic chemicals, such as phosphine, pyrethrins and diatomaceous earth.
Extraction of oil from oilseeds
There are two ways of extraction, depending on the type of the seed.
- Cold-press extraction
The cold-press technique, used in soft fruit, such as olives and some seeds, such as sesame seeds. The cold pressing crushes the oilseed crops without using high temperatures. The result is a fragrant and strong flavored oil, unlike refined oils.
- Oil extraction using solvents
Oilseeds, such as corn, soybeans, cottonseeds or canola, are first crushed.
This separates part of the oil from the seeds into a cake or meal. The oil that remains inside the cake is then extracted with the help of a solvent, such as hexane. The residual mix is then used in animal feed.
Some oils, such as sunflower oil, have a golden-yellow color after the extraction. (4)
The extracted oil, before any further processing, is called crude oil. It contains impurities, contaminants (such as trace metals), phospholipids and solid particles, that must be removed through the refining process.
Refinement of vegetable oils
The result after the refinement is an edible oil. It is clear in appearance, with bland flavor and odor and more resistant to oxidation than before the refining. These products known as vegetable oils.
The refinement process has the following stages:
- Blending. The properties of the final product (e.g. margarine), such as its’ melting point and firmness, depend on what type of fatty acids it contains.
The oils are mixed to achieve the desired outcome. For instance, if the margarine is to be harder, oils with more saturated fatty acids with long chains of hydrocarbons are added.
- Neutralization consists in removing the free fatty acids, which otherwise would cause the margarine to develop a bad taste. This is usually done with a sodium hydroxide solution.
- Washing out trace metals, hydrated phospholipids and soaps.
- Drying the oils after neutralization and washing.
- Bleaching of the oils, by removing the colors, such as chlorophyll, and other impurities with the use of a special absorbent earth, such as acid-activated clay minerals.
- Deodorization to remove any smells and tastes. It consists in heating the oil, blowing steam through it and using a vacuum to remove the steam with smells. It is usually done at temperatures between 180 and 220 degrees Celsius (356 and 428 Fahrenheit).
Margarine is made of about 80% fat and 16% water. (5)
The production of margarine uses vegetable oils, with the purpose of resembling butter as much as possible in taste, texture and properties. The final product is also stable, like butter.
First, before reaching the final result, the oils need to be hardened. This can be done using one of the following three methods:
- Hydrogenation – a controversial process which produces trans fats as a side product. This method is being slowly phased out in many countries, due to the harmful effects of hydrogenated oils, such as the creation of trans fatty acids. (read more..)
- Rearrangement – producing an oil with the desired melting temperature by mixing different oils.
- Fractionation – separating the fat into two fats, that have different levels of solidity at room temperature. This is achieved by separating the high melting point triglycerides by cooling down a liquid oil under controlled conditions.
The margarine production from vegetable oils involves the following steps:
- Blending refined oils with a whole range of ingredients to enhance its physical, chemical and nutritional properties. The ingredients used and their proportion differ, depending on the desired texture of the final product. The following are the most common additives in margarines:
- Vitamins – in many countries fat soluble vitamins A and D are added to make the levels equivalent to those present in butter.
- Colors – usually natural colors, such as beta-carotene.
- Flavors – to achieve a taste similar to butter.
- Emulsifiers – to keep fat and water together and prevent fat float on top. Mono and di-glycerides are the common emulsifiers added to margarine.
- Mixing the blended oils with a mixture of water (or skim milk), whey, brine and some powdered ingredients, such as salt and preservatives, using the emulsifiers previously added.
- Continuing stirring of all ingredients at about 60 degrees Celsius (140 Fahrenheit) to achieve the desired consistency.
- Pasteurizing (killing micro-organisms by increasing the temperature) the emulsion at around 80 degrees Celsius (176 Fahrenheit).
- Solidifying the mixture by chilling it, while it is being kneaded by a series of pins at a required speed.
- To achieve the desired consistency, tempering is used by placing the margarine for 24 hours in low temperatures.
- After the product is chilled, it is ready for packaging and distribution. It is stored at 2-5 degrees Celsius (35.6-41 Fahrenheit).
NUTRITION FACTS VS NUTRITION MYTHS
You will find a summary of the most common nutrition myths and evidence-based nutrition facts here.