As the first step in palm fruit crushing, sterilization is crucial to the quality of palm oil. The main purposes of sterilization are as follows:

Inactivate lipase activity to prevent the rise of free fatty acids; make palm fruit easier to fall off from fruit bunches; soften the peel to make oil easier to separate; kernel modulation reduces kernel fragmentation in subsequent processes;

Horizontal sterilizers are used in the sterilization process. Introduce about 3bar of steam and cook for 60~90 minutes. In recent years, with the development of technology, the sterilization process has gradually developed from intermittent to continuous, which has improved operating efficiency and reduced labor and energy consumption.


The main function of threshing is to separate the palm fruits from the fruit bunches. The sterilized palm fruit bunches are transported to the drum threshing machine. As the drum rotates, the palm fruits are separated from the stems. The stem does not contain any oil, so the losses during the threshing process mainly come from the palm fruits that are still attached to the stem after threshing. If the sterilization time is too short or too long, it will affect the threshing loss. If the sterilization time is too short, it will be difficult to remove the palm fruit; if the sterilization time is too long, the stems will absorb the separated palm oil. Typically, the stems are burned and the ash left behind is used to produce potash, biofuel or transported back to plantations for fertilization.