How soy sauce has impacted edible oil refining.

Edible oil refining is a fundamental food processing technique that can be seen as crucial to feeding the world. Refining can remove many undesired natural components as well as biogenic or anthropogenic contaminants that negatively impact taste, stability and product safety. During refining, deodorization is the most important step to eliminate or reduce undesired volatile and semi-volatile organic compounds such as off-flavours, solvent residues, pesticides, plasticisers, mineral oils, chloroparaffins, PAHs and various other POPs. As a role of thumb, increasing deodorization time and temperature will lead to better removal of semi-volatiles. Opposingly, deodorization can also cause the formation of undesired heat-induced substances. Naturally, there is an inseparable link between refining and analysis of oils & fats, as the latter is the only way to monitor refining success and to ensure product quality.

An issue that has really impacted the analysis and refining of edible oils and fats over the last decade has been the rather coincidental finding of 3-MCPD fatty acid esters in foods by Czech researchers who initially worked on chlorohydrin analysis in soy sauce & HVP. It turned out that 3-MCPD esters are dominantly generated in oils & fats during deodorization. Later, glycidyl esters (GE) were identified also as heat-induced processing contaminants. These findings made it necessary to change refining conditions to overcome the opposing effects of contaminant removal and formation.

This presentation starts with a retrospective view on the early days of analytical method development for 3-MCPD determination. It will show why the early solutions were not accurate, but they were the initial key for the identification of GE. In addition, the astonishing improvements and variations in 3-MCPDE and GE routine analysis are presented. Finally, the occurrence of analytically interfering other halohydrins in refined edible oils is discussed together with an improved analytical methodology.