Enhancing quality and oxidative stability of aged fried food with gamma-tocopherol

To determine the effects of gamma-tocopherol on the stability of fried food, potato chips were fried in triolein with 0, 100, or 400 ppm gamma-tocopherol. Potato chips, sampled at 1, 3, and 6 h of frying time, were aged for 0, 2, and 4 days at 60 degrees C and then evaluated for odor attributes by sensory analysis and for volatile compounds by purge-and-trap gas chromatography-mass spectrometry. Oil sampled after 1, 3, and 6 h of frying time from the fryer was evaluated for total polar compounds and retention of gamma-tocopherol. Oil extracted from the potato chips was also analyzed for residual gamma-tocopherol. gamma-Tocopherol disappeared rapidly, with only slight amounts of the original 100 ppm level detectable after the triolein was used for frying. gamma-Tocopherol significantly inhibited polar compound production in the triolein. Results showed that gamma-tocopherol inhibited the oxidation of the fried food even when only very low levels of retained gamma-tocopherol were present in the frying oil or potato chips. Nonanal formation was inhibited by gamma-tocopherol in aged potato chips. Odor analysis of the aged potato chips showed that samples with 0 ppm gamma-tocopherol had a rancid odor after being aged for 4 days. Potato chips with 400 ppm gamma-tocopherol had no rancid odors; however, as the level of gamma-tocopherol decreased in the triolein and in the potato chips, a weak plastic odor characteristic of oxidized triolein was detected.