THE EFFECT OF PRIMARY ANTIOXIDANTS AND SYNERGISTS ON THE ACTIVITY OF PLANT-EXTRACTS IN LARD

The antioxidant activities of combinations of plant extracts and primary antioxidants or citric acid were studied in lard stored at 75-degrees-C. Methanol extracts of oregano, thyme, marjoram, dittany, rosemary and sage were used. When combined with butylated hydroxyanisole, butylated hydroxytoluene or ascorbyl palmitate the extracts showed an additive antioxidant effect, while combinations with propyl gallate did not increase the induction period obtained by the phenolic antioxidant. Negative synergism was observed when the plant extracts were mixed with DL-alpha-tocopherol. Citric acid showed a high synergistic efficiency with marjoram extract and a minor one with thyme extract, but it had a negative effect with all the others. Ternary mixtures of the plant extracts with citric acid and ascorbyl palmitate had lower activity than the corresponding dual combinations with ascorbyl palmitate, except for the mixture of marjoram extract.