How is Palm Oil Made

Did you know in addition to fresh and packaged food, palm oil is also found in soaps, lipsticks, ice creams, and even, surfactants? Mostly cultivated in tropical countries, palm oil is amongst one of the most highly consumed oils, and its demand has been increasing rapidly. Palm is a fruitful crop, and its production cost is lower than other vegetable oils. 

All these and many more products carry palm oil in one of the other forms.

What is Palm Oil

Palm oil is an edible vegetable oil that is extracted from the fruit of an oil palm tree. It is one of the most adaptable ingredients in the world, and it is added to the most varied things. If you look at the label of your shampoo, a chocolate candy bar, your toothpaste, or a jar of peanut butter, you could easily spot palm oil there in the constituents list. Not just the palm fruit, even its seed, called the palm kernel, is used for oil extraction. 

Want to know how are these palm kernels harvested? Click here!

Here is the anatomy of an oil palm tree. 

Oil Palm tree, palm fruit, and the palm kernel are full of versatility. 

Let us learn a little more about this wonder crop. The oil palm variety used for oil extraction is called the Elaeis guineensis. 

Oil palm tree farms are found majorly in Asian, African, and Latin American countries. Incipiently, the oil palm tree is from West Africa, but, now it is mostly cultivated in Malaysia and Indonesia. In fact, these nations make and supply almost 85% of the palm oil used all over the world.

On average, this oil palm tree has a single stem just like a coconut tree, and it grows up to 66 feet (20 meters) tall and it has long segregated leaves that grow up to almost 5 meters in length. After 3 to 4 years of being planted, it starts producing the palm fruit. The best part is that it is not a seasonal crop, and it yields throughout the year. A single oil palm tree yields as much as 40 kilos of palm and palm kernel oil annually. The fruit that this tree produces is as big as a large-sized olive and grows in big bunches as shown ‘C’ in the picture above.

An oil palm tree carries the fruit in clusters. These bunches weigh somewhere between 10 to 40 kilos. Each olive-like fruit ranges between 6 grams to 20 grams in weight. The structure of the palm fruit has a total of 4 layers including the palm kernel. They can be classified as follows:

1. Exocarp- The outer skin of the palm fruit and has a deep violet brownish tone.
2. Mesocarp- This is the pulp of the fruit which is squeezed to extract the palm oil. Due to the presence of carotene, the color of this layer ranges between dark orange and red. 
3. Endocarp- It is the coarse cast layer between the kernel and the flesh.
4. Kernel- The core of the palm fruit is the seed, which is yellow. This part of the fruit is also used for oil extraction.

History of Palm Oil

The oldest record of the existence of palm oil dates back to 3000 BC. For thousands of years, the practice of palm milling and extraction, for cooking purposes, had existed in West Africa much before the rest of the world discovered it. This thick, flavorful, and almost red colored oil is still an inseparable part of West African cooking. However, the native method of extraction was exhaustive, simple, and not very productive. 

It was only between the 14th and the 17th centuries that palm fruits were taken to the American continent, and then, further to the eastern part of the globe. The palm kernels planted in Asian countries thrived, and the agriculturists realized the commercial potential of oil palm.

In the 1900s, Tener, a highly productive oil palm was discovered. This is when the large production came into being. Then in 1910, the oil palm trees came to Malaysia and saw a boom.  As the industry developed and edible oil usage increased in Western countries, technological improvements were introduced in the palm oil refining process in the latter half of the 20th century. In 1990, Malaysia began to surface as the world leader in growing oil palm trees and production of palm oil.

How is Palm Oil Made in Present Times

Today palm oil is produced on a large- scale through a fully- mechanized process. There is a multiple-step procedure, right from harvesting to obtaining edible palm oil, as shown in the flowchart below. Through this process, a variety of products can be produced from palm fruit. The major products received are:

1. Palm oil- Also known as crude oil, this is a non-bleached virgin palm that is red. This is the first oil product obtained during the making of crude oil. Palm oil is a combination of 50 % saturated fat and 50 % unsaturated fat. It also contains high amounts of vitamin-E and carotene. 

2. Palm kernel oil- This is the oil extracted out of the palm seed. Palm kernel oil is edible but is widely used in cosmetics and cleaning products. At the last stage of crude oil pressing, the nut from the palm fruit is separated. 

 Here are the steps explained in detail: 

1. Reception-Bunches of mature palm fruit, also known as the FFB, are harvested and delivered to the facility, where the fruit is weighed. The fruit gets inspected, graded, and stored for processing. Here is what happens further. 

2. Sterilizing: The sterilization of the palm fruit requires a high-temperature and moist heat treatment. This step utilizes pressurized steam to weaken the stems in the bunch, which makes pulp extraction easier. The heat operation helps destroy oil-splitting proteins and saves the fruit from oxidization. Then, to weaken the pulp structure, the bunches get cooked. This process is important as it treats the mesocarp and also disperses the cells that contain oil to some extent. This also helps the extracted liquid flow swiftly. The moisture produced during sterilization also helps in the removal of gums and resins. The heating and cooling mechanism in this step lets the fruits expand and contract, which lets the kernel get detached from the shell wall. This is what a sterilizer does.

3. Threshing: During the threshing process, the palm fruits are stripped from their stems. The equipment used in this step is called a thresher or a stripper. Here, the sterilized fruit bunches are put inside a rotating or a fixed drum to separate the fruits and the drum. The mass scrap remaining from the threshing is rich in potassium. It is further treated and used as an agricultural fertilizer. The fruit from here moves to the next process. This is how most threshers look.

4. Digestion: This process is followed to break down the cells that contain oil and release the palm oil. The equipment used in this step is a steam-heated barrel-shaped container called the digester. The central rotating shaft inside the digester is equipped with beaters that beat and crush the palm fruit. Digestion is performed under high-heat to suppress the exocarp and free the oil cells and decrease the thickness and stickiness of the oil, at this stage. 

This is how modern digesters and presses look.

5. Pressing: This is the main process through which the extraction of crude palm oil happens. Pressing is performed by two popular methods after digestion. These methods are: 

•  Dry method- This is done with mechanical presses that are used to apply pressure and squeeze out the palm oil from the blend of oil, fiber, moisture, and kernel on the digested mesh. 
• Wet Method- This method uses hot water to separate oil from the fiber, nuts, and moisture.

There are 2 kinds of popular presses used. 

Batch Press System

In the batch pressing method, a heavy metal plunger is used to press the material. In batch operations, the matter is kept inside a large metal enclosure called the ‘cage’. After the material is kept in the cage, it is pressed with the plunger to squeeze out the palm oil. Depending on the size of the facility, the plunger could be manual or motorized. The volume of the cage ranges between 5 kilos and 30 kilos. The batch operation is performed multiple times and the internal pressure is increased gradually to let maximum oil escape the material. The use of hydraulic presses makes the process faster as compared to the manual ones.

Continuous Press System

 This is a uniquely created screw pressing equipment that comprises a barrel-shaped perforated enclosure and a fitting screw. This machinery continuously keeps delivering the digested material from the cage to the terminal. This terminal is restrained by a cone that builds optimum pressure and lets the oil escape through the perforations. 

Clarification

 The obtained crude oil has many impurities. This impure matter consists of solid materials like fruit fibers, loam, and scraps. These are the steps followed for clarification.

Vibration Screen

Water is added to the oil, and with the help of the vibration method, the solid impurities get separated and come to the top. After this, during the separation process, the material on top is isolated through sieving. 

• Suspended solids’ separation- The goal of this step is to achieve this mixture, which comprises 90% palm oil and 10% water. Then, in an oil separation tank, the oil is heated with the help of coils. The heat promotes pressure detachment, and the material that appears in the top section of the tank is secured utilizing a funnel.
• Purification Process- After separation too, there are still some minute solid impurities in the oil. Here, the raw crude oil from the top of the tank is mixed with recovered oil. This mixture needs to go through the purification process, which is enhanced through centrifugal force. By this time, all impurities are removed from the oil and the cake of impurities is separated.
• Oil Drying and Cooling- As there is a lot of water in the oil now, so, it is imperative to dry the oil. So, the oil is exposed to a vacuum evaporating system for drying and cooling.

Palm Kernel Oil Extraction

 At the pressing stage, the kernel and some fiber get separated from the flesh. Then, it is processed separately for the production of palm kernel oil. Here are the steps that are followed after the nut is recovered:

Here is what happens in these steps:

1. Pre-Kernel treatment- Before the kernel gets into the press for oil extraction, it must be cleaned properly. If this is not done efficiently, the debris from the kernels can damage the expensive pressing machinery. Pre kernel treatment is done with the help of magnetic separators for the removal of any metal particles.

 Other things like dirt, rocks, and other material are strained out with the help of vibrating screens. For further treatment, the kernels are put into a grinder that is equipped with a swinging hammer. This increases the surface area of the kernels, which helps in flaking. 

This process is also done with the help of a roller mill in some plants. Many plants follow both the procedures for flaking. All these steps combined reduce the density of seed masses as they keep going up and down in the roller. The flakes obtained are then steam-conditioned in a stack cooker.

 This process ruptures cell walls, reduces the viscosity of the oil, and adjusts the moisture in the meal that would go for pressing further.

Then, in the last stages of pre-treatment, the meals are cooked with steam at a little above 100 degrees celsius.

2. Screw pressing- Once the meal is treated properly and cooked thoroughly, it proceeds to a screw press, which is equipped with a fixed barrel-like structure that has holes in it and an interrupted helical thread. Interrupted helical thread is also called worms. Inside the barrel, the meal is compressed with the action of the worm. The palm kernel oil ejected from the pipe flows through the punctures of the lining bars of the cage. The leftover cake too is released through an annular orifice. This is how a typical pressing plant looks like:

3. Oil clarification: After the expelled oil is collected, like every other oil it has many impurities and particles in it that need to be removed. The oil from pressing sits in a tank initially, and then, it is pumped into a decanter for the removal of larger solid particles. To address the smaller and finer impurities, the oil goes to a filter press. 

Why is Palm Oil Production Unfair to the World

Palm oil is a highly productive crop and yields lots of profits, however between the years 1990 to 2008, it is held to be accountable for almost 8% of global afforestation. Because of the ever-increasing demand for palm oil, many forests have been destroyed to plant more and more oil palm trees in the countries near the equator. This destruction has left many species like rhinos, elephants, and especially, orangutans without a habitat. Devastating environmental hazards like forest fires and climate change have been the effects of irresponsible palm tree farming and unfair harvesting practices.

Next time, when you buy your palm oil just look for the Roundtable on Sustainable Palm oil (RSPO) mark on the palm oil bottle. This is a certification that ensures that the oil you are buying has been cultivated, extracted, and packaged responsibly.

Conclusion

Palm oil manufacturing has come a long way from being entirely done on a handmill to a bunch of processes that require multiple filters, machines, and hands.  This also generates more quality products, however, the cost of palm oil goes far beyond what you see on these very products. There is an environmental cost too, and we need to look at some alternatives. 

If you are looking at some plam oil substitution, click here.