Sources of Sterols

Vegetable Oil Refining

Sterols are contained in Soybean Oil and other vegetable oils. (see Table below) During the refining process, the deodorisation step will produce a steam distillate containing tocopherols and sterols. This is then cooled to form a liquid and separated into Natural Vitamin E and Sterols.

Tocopherols and Sterols are by-products of vegetable oil refining, which, to some extent is in itself a by-product of the animal feed industry. As such availability will depend on the demand for protein and vegetable oil.

The value of the Natural Vitamin E has generally been significantly higher than the Sterols and the Sterols were a by-product of the process to obtain Natural Vitamin E. Suppliers usually will not produce Sterols if profitability for Natural Vitamin E is low. The sterol content in oil is slightly higher than the tocopherols level.

Once the Sterols are separated from the Vitamin E, the liquid is crystallised and sold.

Oil	Tocopherol per Tonne Crude Oil	Sterols per Tonne Crude Oil
Soya	1.180kg	1.534kg
Corn	0.850kg	2.295kg
Cottonseed	0.790kg	2.449kg
Sunflower	0.600kg	1.440kg
Rapeseed/Canola	0.580kg	0.928kg
Peanut	0.280kg	1.120kg

Cottonseed Oil and Corn Oil are not key sources of vegetable oil and the number of commercial refiners is low. Therefore, while availability of sterols is higher from these oils, the lack of raw material source makes them scarce sources of Sterols.

Oils such as Palm Oil, Palm Kernel Oil, and Coconut Oil (Lauric Oils) and Olive Oil are very low in tocopherols while animal oils have essentially no tocopherols. Therefore these are also not a commercially viable source of Vitamin E or Sterols.

Tall Oil Processing

With the introduction of Genetically Modified plants (GMOs) some regions of the world needed a source of Sterols that could be guaranteed to be free from GM. This was found in Pine Trees which are known as “Tall” in Swedish, hence Tall Oil. With no GM trees and no reason to produce a GM tree, this source will always be non-GM.
The trees are felled to produce paper and board. The oil (sap) in the trees is separated into a product called Crude Tall Oil (CTO). This is about 4-5% of the tree, the level of Sterol about 0.08%. The CTO is then processed by distillation and crystallisation to produce Sterol crystals with a purity of between 90% and 98%.

Biodiesel Manufacture

The natural sterols contained in Rapeseed (or Canola in Canada) are removed from the residues of the deacidification process or from the distillates from the production of fatty acid methyl ester and then crystallised with solvents.

Availability and Composition of Sterols

Availability

As indicated above, the quantity of Sterols from Vegetable Seed production will be limited. Soy beans are roughly 82% meal and 18% oil. The refined oil then produces around 260gm of sterols from every 1 tonne of oil refined.

When adjusting for losses in production it requires almost 22,000T of soya beans to be crushed to produce 1T of Sterols. With such economics, the quantity of Vegetable Seed based sterols will always ever be limited to the demand for Animal Feed which is growing at around 3-5% per annum.

Sterols from biodiesel was only produced by one European country until 2013 when a second company developed a process outside of the scope of the patents of the first. They then widely patented their process.

These sterols from biodiesel are currently only available in Europe. With the target to achieve “net zero” on vehicle emissions by 2050, then no new ICE (Internal Combustion Engine) vehicle will be sold within the EU. The EU are hoping that with the average life of a vehicle being 15 years, then by 2050 all of the existing ICE vehicles will have been scrapped.

At present the demand for paper and the global spread pine forests will ensure that there will always be enough Sterols for whatever demand is in the market.

Composition

As single source materials (Rape Seed and Tall Oil) the sterols produced via the Biodiesel Route and the Tall Oil route will produce product which has a consistent level of the individual sterols.

Some of the vegetable oil distillate producers will use a single, or perhaps dual source, of raw material due to the nature of the crops grown in their part of the world. Many producers will need to source distillate from many sources and therefore the product will be a blend of the various sterols depending on what they can source at the time of production.