Evaluation of the mechanism of dilauryl thiodipropionate antioxidant activity

Abstract Dilauryl thiodipropionate (DLTDP) was ineffective as an antioxidant for decomposing lipid hydroperoxides when incorporated into fish oil at concentrations less than 50,000 ppm (0.1 M) at 50 C. However, some general antioxidant properties for DLTDP were observed in fish oil containing 200 ppm DLTDP at 50 C under oxygen for 72 hr. An anomolous prooxidant behavior for DLTDP in fish oil was observed under some conditions of accelerated oxidation which was attributed to the formation of the bisulfite ion free radicals derived from DLTDP degradations. DLTDP was effective for inactivating peracids in model systems containing performic acid and nonanal, ethyl oleate or cholesterol. In these systems DLTDP (2:1 DLTDP:performic acid mole ratio) was preferentially oxidized to the sulfoxide, and prevented the formation of nonanoic acid, 9‐epoxy ethyl oleate and 5,6‐epoxy cholesterol, respectively.