Rosemary extract increased the stability of the tocopherol fractions to a considerable extent. The difference in stability
between the tocopherols was evident in the oil samples that contained rosemary extract, and the sequence of stability
was changed to d > a > b > g. When reducing losses of a-tocopherol, the stabilizing effect of the rosemary extract
is particularly marked, and it is clear that the rosemary extract was slightly more active than the TBHQ at the concentrations used. Gordon and Kourimská (1995) reported that rosemary extract has the ability to slow the loss of tocopherols that are naturally present in vegetable oils. No synergistic effect was observed between rosemary extract and TBHQ, because the treatment with only the natural antioxidant resulted in higher amounts of tocopherols.