Abstract: The effect of individual polyphenols extracted from blueberry leaves on the thermal decomposition of trimethylamine oxide (TMAO) in TMAO-Fe(Ⅱ) model system was studied, and the reaction mechanism was also explored with respect to free radical. The results showed that the individual polyphenols could inhibit the thermal decomposition of TMAO, and reduce the contents of TMA, DMA and FA. The inhibition was more significant at higher concentrations of polyphenols. At the same concentrations, the inhibitory effect of quercetin-3-D-galactoside was better than that of chlorogenic acid. With the increase of temperature, chlorogenic acid and quercetin-3-D-galactosidase significantly inhibited the thermal decomposition of TMAO. When the heating time was less than 75 min, the inhibitory effect of chlorogenic acid and quercetin-3-D-galactoside was significant. The best inhibition of quercetin-3-D-galactosidase and chlorogenic acid was observed at pH 8.0 and 5.0, respectively. Free radicals were produced during the thermal decomposition of TMAO.Chlorogenic acid and quercetin-3-D-galactosidase could inhibit the production of (CH3)3N free radicals in a concentrationdependent fashion. The generation of formaldehyde was suppressed by chlorogenic acid and quercetin-3-D-galactosidase by inhibiting the formation of free radicals.

Key words: blueberry leaf polyphenols, chlorogenic acid, quercetin-3-D-galactoside, TMAO-Fe(Ⅱ) model system, thermal decomposition of TMAO