Understanding how soy lecithin is made is relatively easy, only that different manufacturers vary in their production process. Two significant compounds make up lecithin: cephalin and choline. This article looks at the significance of the two compounds and the entire process of soy lecithin manufacturing to give you a peek behind the curtain here at National Lecithin.
Cephalin and choline are significant in making water and oil emulsions and other ingredients. Choline is considered a better emulsifier of a small amount of oil in larger quantities of water. On the other hand, cephalin is best in emulsifying a small amount of water with more significant oil amounts.
Most commercial lecithins are made from soybeans, although sunflower, canola, and corn also exist. The product is made up of phospholipids and vegetable oils. The phospholipids make up 65% of soy lecithin.
Below is a detailed description of how soy lecithin is made:
Step 1: Soybean Drying Process
Each time soy lecithin manufacturers need beans for production, they dry the beans or hydrate them to achieve the optimum moisture for processing. To begin soy lecithin production, whole soybeans are dried on grain elevators. They are then moved to an oven and exposed to temperatures between 60 (140 °F) and 88° C (190.4 °F).
After drying, they move down a conveyor belt and are crushed into soybean flakes. The flakes are allowed to cool to 69° C and then mixed with hexanes to extract lecithin.
Step 2: Crude Oil Degumming Process
In the batch method, crude oil from the crushed soybean flakes is added to the reactor. The reactor temperatures are about 70 (158°F) and 82 °C (179.6°F). Acetic anhydride and 3% water are added to the mixture and continuously stirred. Hydration takes place here as water and oil will react for a total of 60 minutes. The product formed from hydration is moved to the degumming centrifuge.
Oil hydration and phospholipid isolation are the standard methods used in crude soybean oil production. Degumming happens in pipelines where raw crude soybean oil is produced continuously. At this level, crude soy oil contains an average of 1.8% hydratable compounds, primarily lecithin phosphatides.
Step 3: Soy Lecithin Isolation from Soybean Oil
At this point, we already have crude soybean oil. Dehydration ensues; oil and phospholipids are isolated. Further dehydration with a thin film evaporator is also done to dehydrate the isolate further. Alternatively, intermittent and continuous dehydration are also viable methods.
While using continuous dehydration, a thin film evaporator is used to evaporate the content for 2 minutes under pressure and temperatures of 115 ° C. During evaporation, you must ensure the final product attains a moisture content of 0.5% and below. Since it’s in the form of a dehydrated jelly, it must be quickly cooled to temperatures below 50° C to prevent dark color from forming.
Colloidal phospholipids are usually stored for more than a few hours to avoid bacterial spoilage. To achieve this, diluted hydrogen peroxide is added to the gel, which revives and prevents bacterial growth.
Step 4: De-coloring Process
In the decolorization stage, 3% of hydrogen peroxide is used to decolorize the content. Alternatively, 1.5% of benzoyl peroxide can serve the same purpose. Hydrogen peroxide is best at reducing brown pigments; hence very useful in treating yellow color. Benzoyl peroxide is good at reducing red hence its use in treating red.
The two decolorizing agents make it easy to achieve phospholipids that have light colors. Ensuring the process takes place at 70° C to achieve the desired outcomes is essential when decolorizing.
Step 5: Drying
There are three methods used in the drying of phospholipids:
- Batch drying
- Film drying
- Vacuum drying.
Vacuum drying is considered the most reasonable method, while batch drying is the most common. Vacuum drying poses some challenges as the phospholipids must not foam during drying.
Film drying is very beneficial as it prevents phospholipids from blackening while cooling. It’s also good at extracting acetic acid residue that was added during the degumming process. Temperatures in the vacuum must be constantly monitored despite the extended drying period (3-4 hours).
Step 6: Soy Lecithin Refining
During the refinery process, fatty acids, soybean oil, including other impurities, are removed from the crude phospholipids. This is done to ensure a higher content of phospholipids is attained. The ratio in which soy lecithin and acetone are prepared is critical as they are put in the ratio of 1:(3-5), respectively.
Here constant stirring is done while the phospholipids undergo cooling. Fatty acids and oil will dissolve in acetone while phospholipids precipitate and are separated and stored as refined soy lecithin.
Regardless of whether the end product is bleached, it’s considered “natural lecithin” or “unrefined lecithin” as it still contains 30-35% crude soy oil and 65-70% phosphatides. To get the dry granular product known as refined lecithin, the oil in unrefined lecithin must be extracted with acetone.
Uses of Soy Lecithin
With the chemical composition of soy lecithin, there are extensive ways in which it can be used depending on the need.
- Cosmetic Industry: Since soy lecithin has binding properties, it is becoming a common ingredient in the cosmetic industry. It’s used in various skin care products where it helps in making the skin soft and smooth.
- Food Uses: Soy Lecithin is used in most of our daily foods. For instance, it’s widely used in margarine as an emulsifier and anti-splatter. Soy lecithin in chocolate and caramels ensures the products have the right crystallization, viscosity, and sticking. It’s a common ingredient in baked foods, meat, poultry products, and dairy products, where it acts as an emulsifier and digestion enhancer.
- Industrial Uses: Despite soy lecithin appearing to be of much use in the food industry, it’s also used in the petroleum industry, textile, leather, pharmaceuticals, and paper printing, among others.
- Therapeutic Uses: More research is still underway to prove that soy lecithin is effective in treating cardiovascular and neurochemical disorders. The results of the therapeutic use of soy lecithin might not be conclusive.
There are many manufacturers and distributors of lecithin for commercial or industrial purposes. When sourcing yours, make sure to get it from a manufacturer that uses chemical-free methods of extraction and preservation and meets Global Standards for Food Safety.
Contact us today for all your lecithin needs. We can supply small quantities or truckloads for larger needs. We are your number one lecithin supplier, shipping all over the United States and Canada.