Vegetable cooking oil is one of the most commonly used cooking oil in Indonesia. There are many variants of cooking oil, such as olive oil, corn oil, and palm oil, but palm oil is most commonly used on a daily basis. Especially because Indonesia is the world’s largest palm oil producer in the world, churning out more than 40 million tons per year.
How palm cooking oil is produced:
1. Oil Palm Fruit Collection
Ripe oil palms fruits of good quality are harvested while still in bunches. The Fresh Fruit Bunches (FFBs) are then taken to the palm oil mill.
2. Boiling Oil Palm Fruit
At the mill, the FFBs are sterilized using hot water steam with a pressure of between 2.2 to 3 kilograms per centimeter for about 90 minutes. The boiling is to kill enzymes that can damage oil yields and also make the process of removing the flesh of the fruit from the shell.
3. Threshing the Fruit
The FFBs are then stripped of their fruit by threshing a process that is made easier by the previous boiling process. The FFBs are then passed through a thresher machine to separate the fruit from the spikelets and stalks.
4. Pressing the Fruit
Before the fruits are smashed, they are steamed again at a temperature of 80 to 90 degrees to separate the pulp from the kernel. The pulp would then go through a pressing machine to extract the oil. What comes out from this machine is still a raw crude oil that contains pulp fibres.
5. Clarification Process
The oil is then diluted with water and filtered through a screen to help remove debris and impurities.The waste collected from this process will be screened again using a Depericarper machine to extract any oil still contained in it.
6. Drying Process
The oil is then put through a drying process to rid it from any leftover water content from the steaming process. In the light phase, where the oil contains a low concentration of suspended solids it is put through a continuous settling tank before it enters the oil tank. If the concentration of solids and water is high, the oil is first put through a sludge tank and later a sludge separator before the oil goes to the oil tank.
7. Oil Refining
Oil that has been separated from water is not 100 percent free from water and thus requires a refining process. The oil is passed through a vacuum dryer to remove water content until the oil volume reaches at least the threshold level or below it. The produced oil is then considered a pure oil and put into the oil storage tank before taken to the packaging section. Oil purification is also generally carried out in two refining processes so that it can produce cleaner cooking oil.