Frying Performance of Gallic Acid and/or Methyl Gallate Accompanied by Phosphatidylcholine

This study shows the possibility of using gallic acid (GA) and/or methyl gallate (MG) accompanied by phosphatidylcholine (PC) instead of tert-butylhydoquinone (TBHQ) for frying purposes. The antioxidants and PC were added in the concentrations of 1.2 mM and 500-2000 mg/kg, respectively. Oxidative stability index (OSI) and the kinetics of change in conjugated dienes (LCD), carbonyls (LCO), and acid value (AV) were used to assess the antioxidative treatments. GA alone and GA/MG (50:50) plus PC at 2000 mg/kg yielded the same OSI as that of TBHQ (18.4 h). The latter was of the highest frying performance in preventing the formation of LCD (r_n = 0.0517/h and t_T = 10.6 h vs. r_n = 0.0976/h and t_T = 4.5 h for TBHQ), LCO (r_n = 0.0411/h and t_T = 12.7 h vs. r_n = 0.15/h and t_T = 4.3 h for TBHQ), and hydrolytic products (AV_m = 37.8 vs. 24.0 for TBHQ); r_n: normalized the maximum rate of LCD/LCO accumulation; t_T: the time at which the rate of LCD/LCO accumulation is maximized; AV_m: quantitative measure of hydrolytic stability.