Cottonseed oil. Not generally found on supermarket shelves and often considered a by-product of the cotton fibre production process, cottonseed oil is a less-known and often undervalued plant-based oil. Nevertheless, it is incredibly healthy, useful and versatile. As its diverse uses become more commonly known, the market for cottonseed oil is only expanding.
There is no better time than the present to set up a cottonseed oil manufacturing plant. Though the cottonseed oil manufacturing process has its fair share of complexities, stepping into this industry is well worth the investment. Because producing cottonseed oil is more than just extracting one component from a raw material - it is stepping into a complex value chain that uses every component of the cotton plant. It implies a much needed step towards a circular economy in which the cottonseed oil extraction process is part of a larger ecosystem that also contributes towards biofuel, animal feed, cosmetics, insecticides, food processing, and other industries.
As you dive into understanding the cottonseed oil production process, let us give you a glimpse into what it involves - the cultivation and preparation of cottonseed; the market for cottonseed oil and related products; extracting cottonseed oil and refining it; and the equipment you'll need to produce high quality cottonseed oil that matches international standards.
What is cottonseed oil? Characteristics and applications
Incredibly versatile but often undervalued, cottonseed oil is extracted from the seeds of cotton plants of different species, primarily Gossypium hirsutum and Gossypium herbaceum. Whole cottonseed stands out from other plant-based protein sources in that it boasts of both high energy and high fibre. Raw cottonseeds comprise 23% protein and 20% fat in the meaty kernel and 24% crude fibre in the linters that cover the seed.
Nutritionally, cottonseed oil boasts of high levels of antioxidants like vitamin E, imparting it with health benefits and good storage stability. When refined, bleached and deodorized (RBD) to make it suitable for human consumption, cottonseed oil has a neutral taste and a light golden colour. It has a high smoke point and light consistency.
It is considered a healthy vegetable oil because it has a high concentration of unsaturated fats. Interestingly, it is one of the most unsaturated edible oils we know, with twice the polyunsaturated fatty acids compared to its saturated fatty acid content: it has about 42 to 52% linoleic acid (polyunsaturated) and 26 to 35% palmitic and stearic acid (saturated), while the remaining 18 to 24% is accounted for by oleic acid (monounsaturated).
All of these qualities make cottonseed oil valuable in different industries and the cottonseed oil manufacturing process fairly lucrative.
Cottonseed oil is used in food processing industries, especially as a cost-effective alternative to canola oil or coconut oil. Its high smoke point, light consistency, and flavour-enhancing qualities make it great for frying - it is used to make potato chips, crackers, pretzels and many other snacks. This oil also lends food products a creamy texture, making it a great choice for the production of mayonnaise, margarine, and salad dressings.
As an emollient and source of vitamin E, cottonseed oil is considered to boost skin health by stimulating new cell growth and protecting against infections. In the cosmetics industry, cottonseed oil is used to produce soaps and ointments for eczema and psoriasis, while other ingredients derived from cottonseeds are used to make lipsticks, balms, eye makeup, cleansers, and more.
Cottonseed comprises the naturally occurring compound gossypol, which lends it a toxicity that must be inactivated before its products can be consumed by humans. But when left activated, gossypol makes cottonseed oil a potent insecticide that can keep away whiteflies, spider mites and other pests from fields and plantations.
Given the high protein content of cottonseed, the meal left over from the cottonseed oil extraction process can be used as a high-protein and high-energy feed or feed supplement for cattle, swine, poultry and even farmed shrimp.
Cottonseed oil and other products derived from the plant also have other agricultural and industrial applications, like in the production of mulch and green fuels. And of course, one of the main reasons why cotton was cultivated in the first place - for its fluffy white fibres which are used to make fabrics that can are used to stitch everything from clothes to curtains and beyond.
Why set up a cottonseed oil manufacturing plant? The market for cottonseed oil
Cottonseed cultivation has been around for time immemorial. As far back as the fifth millennium BC, simple handheld devices were used in India to clean cotton fibre from the plant to make fabric. Over the centuries, cotton grew in popularity, especially because it could be grown easily almost anywhere, whether the region was inland or coastal.
Even though cotton production yielded twice as much seed by weight compared to cotton fibres, the seeds were initially considered worthless byproducts. Decomposing the seeds gave off an unpleasant odour, while attempts to burn them left them smoldering. For centuries, cotton fibres were the primary product while the seed was used almost exclusively to supplement cattle feed.
Over time, cottonseed processors began to find new ways to process everything that was left behind from fibre production. Oleomargarine and compound lard emerged as butter substitutes. Cottonseed oil was used as an animal fat alternative in the production of soap. Cottonseed oil also emerged as a popular cooking oil, especially in the early 1900's in the USA.
Today, cottonseed is a leading cash crop in the United States and one of the top five oilseeds globally. In 2019, the world produced about 4.5 million tonnes of this oilseed, with China, India, Pakistan, Brazil, the USA, and Turkey leading the charge.
Though cotton fibres are a large reason why cotton is cultivated, cottonseeds and cottonseed oil are increasingly getting the attention that they deserve for their utility and versatility. As the technology for the cottonseed oil manufacturing process develops, the market for cottonseed oil and its derivatives is growing. The worldwide demand for healthy vegetable oils and the discovery of new industrial applications is also driving the growth of the cottonseed oil market.
In other words, every component of the cotton crop has great market potential. At Kumar, we encourage new plant owners to not only get started on the cottonseed oil production process but also get involved in multiple aspects of the value chain. This presents opportunities for added revenue generation and makes cottonseed oil producers champions of sustainability and circular economy. Globally, the cottonseed oil and allied products market is posed for long-term growth.
The cottonseed oil manufacturing process
Cotton plans generally take 6 to 8 months to mature after they are planted. On maturity, the protective casings - referred to as bolls - open up to expose the soft fibres, called lint, that are inside. Historically, these open bolls were handpicked but today, we have machines which pick and strip the bolls from the crop. Subsequently, the cotton is "ginned" to separate the lint from the seed.
Your first step in the cottonseed oil production process would be to source good quality seeds. The quality of oil you produce and the sustainability of your product will depend, to a large extent, on the manner in which the cottonseeds are cultivated and harvested. To produce a high quality, truly sustainable product, it is essential for you to source your raw materials from suppliers you trust.
Let us walk you through the entire cottonseed oil manufacturing process - from oilseed preparation to extraction and refining. As champions of sustainability, every step of the way, we will note the by-products that are produced and how you can extract value from them.
Preparing cottonseeds for oil extraction
Seed cleaning. When cottonseeds are transported from fields or warehouses to your cottonseed oil manufacturing plant, they may have sticks, stones, dirt and other unwanted materials mixed in with them. If these materials go through your processing equipment, the equipment may be damaged and the quality of your final product will be compromised. You must use an effective seed cleaning machine to eliminate undesirable components from the raw material you have sourced.
Delinting. Even after the lint is separated from the seed, sometimes small strands of cellulose remain stuck to the seed. These "linters" clog to your processing equipment, come in the way of the movement of raw material through the system, and affect the functioning and longevity of your cottonseed oil manufacturing plant.
After seed cleaning, it is important to delint it i.e. remove the residual white fuzz that remains on the cottonseeds. You may receive cottonseeds which have about 8 to 10% lint by weight. You must delint the seeds till the lint remains only 1 to 2% of the mass of the raw material.
These linters aren't waste material. They can be used as other cotton fibres are, to produce clothing, surgical dressing, etc. Interestingly, the cellulose from linters is also valuable in the production of x-ray films, explosives, computer screens, and plastics.
The next step? Dehulling. Dehulling involves removing the abrasive hulls which make up about a quarter of the cottonseed by weight.
Again, the separated hulls are of great value. They may be used to supplement animal feed, as mulch, or as fuel for oil mills. The ashes produced in the latter process can also be bleached to make lye for soap production.
Finally comes conditioning. Cottonseeds must be properly pre-treated to minimise the presence of the toxic pigment gossypol in the extracted cottonseed oil. This isn't an easy process - gossypol is only toxic in its free state, so when you treat it with heat, it binds to solid proteins and deactivates; on the other hand, overheating it can reduce protein availability, making the meal less attractive to producers of animal feed. Cottonseeds must be conditioned under the optimum environmental conditions to ensure the gossypol is deactivated without the loss of nutrients.
Typically, cottonseed oil manufacturers invest in multiple pieces of machinery - crackers, rollers, flakers, stack cookers, dryers, and/or rotary steam vessels - to prepare the cottonseeds effectively for oil extraction.
Alternatively, there is a single piece of equipment to get the job done. Enter the Anderson Dox™ Extruder. This extrusion system combines multiple processes into one piece of machinery. It does the work of multiple stacked cookers to cook, dry and shear cottonseeds - that too with lower energy requirements and consequently, costs. The Extruder also makes cottonseed oil more available for extraction by effectively rupturing the cell wall, denaturing proteins, binding gossypol to the meal, and destroying bacteria.
While you can rely on multiple pieces of equipment to prepare your cottonseeds, depending on the requirements of your project, we may recommend investing in the Anderson Dox™ Extruder for the efficiencies it offers in terms of speed, cost and resource utilization.
The cottonseed oil extraction process
Cottonseed oil extraction is far simpler than cottonseed preparation. You can feed the prepared raw material into a screw press like our New Super Press Series Oil Expeller or our New Oil-N-Oil Series Oil Expeller. As with any mechanical extraction, pressure is exerted on the feed to separate the oil from the meal. In an ideal scenario, residual oil in the meal in 6% or less.
The remaining meal or cake is ground into an appropriate size for solvent extraction. Solvent extraction using a solvent like hexane can extract the remaining oil content from the cake.
All the cottonseed oil extracted from mechanical and solvent extraction is washed and then redirected to a cottonseed oil refinery plant where it is made suitable for consumption by human beings.
The role of cottonseed oil refinery plants
Well processed cottonseed oil is black in colour, but if it has a reddish tinge to it, it could mean that it still has high levels of gossypol in it. Refining cottonseed oil is essential to remove this gossypol which can cause harm or even death in those who consume it.
The typical cottonseed oil refining process includes alkali refining or neutralisation, bleaching, winterization, and deodorization.
Alkali refining, or chemical refining, is the process of using an alkaline solution to remove free fatty acids (FFAs) from crude cottonseed oil. This chemical reaction results in the production of soap stock, which settles at the bottom of the tank and is removed using centrifugation. This soap stock offers great opportunities for downstream value addition as it can be split into a fatty acid called acid oil which serves as a raw material in detergent and biodiesel production.
Next comes bleaching, which involves the removal of unwanted colours, phosphorus, residual soap, peroxide, and metal contaminants. You can rely on our Ecopure Bleacher or Stable Bleacher for this process.
Winterization, also called fractionation, is the process in which high melting triglycerides, which result in the formation of turbid oil during cold weather, are separated from the oil.
Finally, deodorization helps clean cottonseed oil of volatile components which give the crude oil an unwanted odour. Depending on your particular project, our Ecopack Deodorizer, Ecosteam Deodorizer, or Crown's Diflow Deodorizer may work best for you.
There you have it. The cottonseed oil refining process.
Your partner in the cottonseed oil manufacturing process
At Kumar, our innovative engineering solutions and superior manufacturing standards help you optimise operating costs and improve efficiency. We dedicate ourselves to every project we take on to ensure a successful outcome for your company. We've delivered over 700 projects to over 500 customers in more than 74 countries. Let us help you deliver your next one successfully.
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