The antioxidative activity of RRR-α-tocopherol vs RRR-δ-tocopherol in combination with ascorbyl palmitate in cooked, minced turkey

RRR-α-tocopherol and RRR-δ-tocopheroI (100 or 200 ppm) had similar and significantly better antioxidative effects compared to ascorbyl palmitate (200 ppm) in turkey meat balls during storage at 5 °C for up to 9 days, as determined by measurement of thiobarbituric acid reactive substances (TBARS) and by static head space detection of hexanal. The antioxidative effect of α-tocopherol at 100 ppm was, measured as a reduction of head space hexanal, significantly enhanced by ascorbyl palmitate (200 ppm), resulting in a further 50% reduction compared to δ-tocopherol. At the 200-ppm level, only the antioxidative activity of α-tocopherol was enhanced significantly by ascorbyl palmitate (200 ppm), in contrast to the effect on the antioxidative activity of δ-tocopherol (200 ppm). The antioxidative activity obtained by α-tocopherol at the 100-ppm level in combination with ascorbyl palmitate (200 ppm) was similar to the effect obtained by α-tocopherol at the 200-ppm level in combination with ascorbyl palmitate (200 ppm) measured as head space hexanal. Ascorbyl palmitate was in all storage experiments depleted in the product at a rate which appeared to be independent of the presence of tocopherols. Of the tocopherol homologues, α-tocopherol was most affected by the presence of ascorbyl palmitate, and the concentration of α-tocopherol was found to decrease during storage in the absence of ascorbyl palmitate, in contrast to when ascorbyl palmitate was present. A similar effect of ascorbyl palmitate was less evident for δ-tocopherol and for γ-tocopherol in a natural mixture of the tocopherol homologues added to turkey meat balls.