The studied OFMs are SA, a carboxylic acid containing a saturated C 18 tailgroup, GMS, a glyceride mono-ester containing a saturated C 18 tailgroup, and GMO, a glyceride ester containing a C 18 tailgroup with a Z-double bond in the middle of the chain. While SA is commonly used as a prototypical OFM, it is no longer used in commercial formulations due to its acidic nature, and has been replaced with amines, amides, and esters, such as GMS and GMO. The molecular structures of the OFMs are shown in Fig. .