Sterilization of fresh palm oil fruit - a reliability of existing and advanced technologies; and environmental impacts

Abstract

Sterilization of fresh fruit bunch has become the most important process in the palm oil processing as it is needed in order to inactivate lipase enzyme that causes oil deterioration. The process facilitates the detachment of oil palm fruits from the bunch and conditions the nuts for the subsequent processes downstream. Commonly, steam sterilization process was used in majority palm oil mills in the tropical countries like Malaysia, Indonesia etc. Steam sterilization was known to inactivate the lipase enzyme and conserve the palm oil quality. However, at the same time this technique generated palm oil mill effluent which can be considered as an environmental threat. The treatment of effluent needed long duration. However, its productions were overwhelming. As a result, more land needed to be explored for the effluent storage and treatment. So, researchers are trying to find out the eco-friendly system of sterilization to reduce the production of effluent. In this regard, sterilization of oil using supercritical technique, which operated at high pressure at low temperature was found to be suitable. In terms of oil quality, it can preserve the phytonutrients in the oil because nutrients of oil easily degraded when operated at high temperature. Moreover, this environmental friendly technology could solve the problem of the effluent discharge and space as it does not contribute to the effluent because there is no water involved in the process. So, the supercritical carbon dioxide sterilization is considered an appropriate tool and it was proposed as an alternative to replace the steam sterilization in palm oil production technology.