It has been reported that Lactobacillus plantarum exhibited galloyl-esterase and decarboxylase activities which allowed hydrolysis of the grape seed polyphenols and leads to the formation of gallic acid and pyrogallol, respectively [18]. In addition, different kinds of esterases from Bacillus subtilis have been isolated and demonstrated to hydrolyze various esters [19]–[21]. Therefore, we selected these two bacteria to assess their impact on TFDG metabolism. Lactobacillus plantarum 299v and Bacillus subtilis were incubated with TFDG and samples were collected as a function of time (up to 72 h) and analyzed by HPLC-ECD and LC/MS. Figure 7 shows the representative HPLC chromatograms of TFDG incubated with Lactobacillus plantarum 299v (Figure 7A) and Bacillus subtilis (Figure 7B). TFDG was degraded progressively with time increasing. PG, GA, TF, TF3G and TF3′G (M1–M5) were identified as the metabolites of TFDG by comparing their retention time and tandem mass data with those of the authentic standards (data not shown).