Fatty acid esters of 3-monochloropropane-1,2-diol and glycidol in palm oil: A review on current industrial-scale mitigation strategies, challenges and perspectives

Glycidyl ester (GE) and 3-monochloropropane-1,2-diol ester (3-MCPDE) are food contaminants formed during edible oil refining. Due to their potential human carcinogenicity, the European Commission has established regulatory limits for vegetable oil, including palm oil. While laboratory-scale studies have shown promising reductions, large-scale implementation remains challenging. This review examines current mitigation technologies for palm oil, evaluated from lab to plant scale, and explores the challenges of large-scale implementation. Effective methods, such as crude palm oil washing, bleaching with non-hydrochloric acid-activated bleaching earth, dual-temperature deodorisation, and double refining, have been successfully tested at pilot scale or larger. Particularly, crude palm oil washing is widely adopted to reduce 3-MCPDE, whereas double refining effectively targets GE. However, a combination of strategies is required to simultaneously reduce 3-MCPDE and GE. These measures often lead to increased costs, oil loss and wastewater generation, with potential impacts on product quality. Furthermore, maintaining crude palm oil quality through good harvesting and milling practices is essential for consistent mitigation results. Continued research is necessary to improve mitigation methods for greater cost efficiency and reduced environmental impact, with large-scale studies needed to validate lab-scale findings and facilitate industry adoption.