Lecithin is one of the most popular commercial emulsification agents carrying multiple fatty acids, glycerol, and phosphate. It is commonly used in various manufacturing industries with a dominant presence in processed food and chocolate production. Naturally, it can be extracted from the cell membrane of different plants and animal cells.
However, since it holds a commercially high demand, it is extracted from genetically modified soybean crops. The final product or soy lecithin has a plastic-like consistency and is usually a dark or mild reddish brown in colour.
How is Soy Lecithin made?
Now, let’s deep dive into the process of transforming soybeans into soy lecithin.
To extract the highest quality lecithin, careful processing is required. Once the oil has been extracted from soybeans, it must go through the following 5 steps before lecithin can be finally obtained:
● Degumming
● Separation
● Bleaching
● Fluidizing
● Drying and Cooling
Here’s a detailed look at each stage.
Stage 1: Degumming
The degumming process involves hydrating lecithin (present at the time in the oil) enough that it can easily be separated from the oil. This is done by adding water to the crude soy oil and mixing it for about an hour. The mixing time can vary depending on its speed.
The hydratable components in crude soy oil are also called lecithin phosphatide. Its presence is only about 1.8% of the totality of crude oil.
Stage 2: Separation
Once enough water has been added and mixed the phosphatides begin to agglomerate together to form a viscous mud-like sludge. The oil then goes through a centrifuge to separate this sludge or heavy mass.
Stage 3: Bleaching
The separated sludge is actual lecithin. However, at this stage, it has a water emulsion of about 25–50%. Depending on the industry soy lecithin is being produced for, it may then undergo bleaching. Bleaching helps tone down the colour of lecithin from brown or beige to pale yellow usually using hydrogen peroxide.
Stage 4: Fluidizing
This bleached mixture is extremely viscous and has a honey-like consistency. Once cooled, the mixture becomes difficult to handle. To lower its viscosity, fluidizing agents are added to it. These may include soy oil, fatty acids, or calcium chloride.
Stage 5: Drying & Cooling
After fluidizing, the mixture undergoes a drying process through Film Driers or Batch Driers. When it has been dried and cooled, the mixture is left with only 1 per cent moisture content.
The Final Product
Bleached lecithin is called unrefined lecithin or natural lecithin. It has ‘water in oil’ and ‘oil in water’ emulsifying capabilities. At this stage, it contains 65 to 70% phosphatides & 30 to 35% crude soy oil.
To transform it into granular form, the oil is removed by acetone extraction leaving behind refined lecithin granules.
Other soy lecithin modification techniques that enhance the emulsification properties include:
● Fractionation in alcohol
● Hydrolysis (enzymatic, acid, or alkali)
● Acetylation
● Hydroxylation
Common Concerns Related to Soy Lecithin
Lecithin has grown in importance as an ingredient in nutraceuticals and dietary supplements during the past few decades. It’s important to note that it’s an ingredient in many popular vitamin supplements and weight loss products around the world today.
Soybeans have historically been the primary source of lecithin around the globe, but alternative sources, such as canola and sunflower, are now being sought after due to rising demand for non-GMO lecithin. The European market prefers non-GMO lecithin even though studies have proven that lecithin from GMO soybeans is equal to that from non-GMO varieties.
The fact that soy is an allergic food is widely known. The protein fraction contains the allergens from soybeans. The production of soy lecithin removes the vast bulk of this protein. Trace amounts of soy proteins, including soy allergens, have been discovered in soy lecithin. However, the majority of people who are sensitive to soy do not have allergic responses to soy lecithin because it does not contain enough soy protein residues.
Industries do, however, support the source labelling of lecithin when it is used as a direct food component since there is, of course, a chance that some of the more sensitive soybean-allergic people may react to ingesting it.
Closing Words
Soy lecithin is a good example of how a compound taken from nature is used for human benefit. In fact, soy lecithin owes all its many uses to the fact that it is extracted from soybeans.
Soy Lecithin is made by degumming Crude soy oil. The resultant mass is bleached, dried, and refined to get the best emulsifying properties.
