Abstract
The effects of several synergists along with a mixed tocopherols concentrate (m-Toc) on the oxidative deterioration of a high linoleic margarine were compared with those of phenolic antioxidants. The margarine was prepared with blended vegetable oils, mainly safflower oil, whose levels of linoleic and oleic acids were 54.8 and 19.6% to the total fatty acids, respectively. Stability of the margarine against oxidative deterioration was evaluated based on changes in the peroxide value and vitamin A and β-carotene content during storage at 20°C.
1) On oxidation of high linoleic margarine, each tested amino acid except L-proline (Pro) enhanced the effect of m-Toc in the order of L-histidine (His)>L-cystine (Cys)>L-tryptophane (Trp)>glycine. The addition of His or Cys along with m-Toc was the most effective and comparable to that of dibutylhydroxytoluene (BHT) alone. In contrast, L-ascorbyl stearate (AS) and Pro lessened the effect of m-Toc.
2) The effects of synergists along with m-Toc on the stability of vitamin A or β-carotene in the margarine were essentially the same as those on oxidation. The effect of His along with m-Toc, in particular, was superior to that of BHT alone.
3) Amino acids, such as His, Cys or Trp, clearly showed protective effects on the loss of Toc, particularly α-Toc in the margarine, but no effect was observed in AS. BHT and t-butyl-hydroquinone were also somewhat effective.
