Phytosterols inhibit the formation of 3-monochloropropane-1,2-diol esters in model reactions and the possible mechanism

The effects of three phytosterols (β-sitosterol, stigmasterol, and campesterol) on the formation of 3-monochloropropane-1,2-diol (3-MCPD) esters and the possible mechanism were investigated in this study. Model reaction with 1,2-dipalmitoyl-sn-glycerol (DPG) and sodium chloride as the reacting precursors was adopted to investigate effects of three phytosterols on the formation of 3-MCPD esters. The results showed that three phytosterols exhibited inhibiting activity on the formation of 3-MCPD esters in the model reactions. ESR signal detection indicated that the phytosterols suppressed the formation of free radical in the model reactions. In addtion, 3-chloro-Δ5-cholestenes were detected in the reaction models by using UPLC-APCI-MS. It suggested that phytosterols reacted with chloride and transformed to 3-chloro-Δ5-cholestenes. Therefore, the possible mechanism of phytosterols inhibiting the formation of 3-MCPD esters could be proposed that phytosterols suppressed formation of free radical intermediates in model reactions and competed with DPG for chloride ion to reduce the formation of 3-MCPD esters.