Studies on the Improvement of Antioxidant Effect of Tocopherols. X.

Abstract

Following the same procedure described in the previous report Yukagaku, 34, 48 (1985), the fry test was conducted so as to compare the efficiency of tocopherol (Toc) with those of other several antioxidants and investigate the synergistic effects of antioxidants along with those of Toc on the oxidation of fried foods. This test was also carried out on L-ascorbyl stearate (AS), lecithin and sucrose fatty acid esters (SE).1) In the case of potato chips fried in a lard system containing only one of the antioxidants at a time, the time required to attain POV 30 of the chip lipid fraction and for odor to be perceivable during storage at 60°C was in the order of a mixture of d-Tocs (m-Toc) =t-butyl hydroquinone (TBHQ) >propyl gallate (PG) >dibutyl hydroxytoluene (BHT). This order agreed with the results from the transference ratio of each antioxidant to the potato chips (=proportion of antioxidant content in the chip lipid fraction to that added to the lard system).2) Synergistic effects on the oxidation of potato chips come about as a result of TBHQ treatment or that of PG with m-Toc. However, the effects resulting from treatment with BHT with m-Toc were the equivalent of the combined effects of all the components. However, treatment with isopropyl citrate and m-Toc together was almost the same as that resulting from m-Tocalone.3) All tested synergists were found to cause m-Toc to have greater effect on the potato chips. The time required to attain POV 30 during storage at 60°C of lecithin>AS>SE. However, addition of lecithin or SE to the fry fat resulted in browning of the potato chips and bubbling of the fat.