Optimal tocopherol concentrations to inhibit soybean oil oxidation

Abstract

The optimal concentration for tocopherols to inhibit soybean oil oxidation was determined for individual tocopherols (α-, γ-, and δ-tocopherol) and for the natural soybean oil tocopherol mixture (tocopherol ratio of 1:13:5 for α-, γ-, and δ-tocopherol, respectively). The concentration of the individual tocopherols influenced oil oxidation rates, and the optimal concentrations were unique for each tocopherol. For example, the optimal concentrations for α-tocopherol and γ-tocopherol were ~100 and 300 ppm, respectively, whereas δ-tocopherol did not exhibit a distinct concentration optimum at the levels studied (P < 0.05). The optimal concentration for the natural tocopherol mixture ranged between 340 and 660 ppm tocopherols (P < 0.05). The antioxidant activity of the tocopherols diminished when the tocopherol levels exceeded their optimal concentrations. Above their optimal concentrations, the individual tocopherols and the tocopherol mixture exhibited prooxidation behavior that was more pronounced with increasing temperature from 40 to 60°C (P < 0.05). A comparison of the antioxidant activity of the individual tocopherols at their optimal concentrations revealed that α-tocopherol (~100 ppm) was 3-5 times more potent than γ-tocopherol (~300 ppm) and 16-32 times more potent than δ-tocopherol (~1900 ppm).Paper no. J9908 in JAOCS 79, 47-51 (January 2002).

Influence of sn‐1,3‐lipase‐catalysed interesterification on the oxidative stability of soybean oil‐based structured lipids

“…Some researchers reported that α-TOH showed slight pro-oxidant effect at concentrations above 250 ppm. 7,19 Similarly, there have been reports that addition of α-TOH to canola or fish-oil-based SLs either did not change or only slightly increased the oxidative stability of oil. 16 Both AP and Le, when used alone at the 200 and 1000 ppm level, respectively, improved the oxidative stability of SL.…”

“…6 A TOH mix was prepared using individual TOH solutions to produce a TOH profile that was similar to that in SBO. 7 Thus, 50 ppm α-TOH, 50 ppm β-TOH, 700 ppm γ -TOH, and 250 ppm δ-TOH were added to purified TAGs obtained from SL.…”

“…Even above 1000 ppm, δ-TOH is not a pro-oxidant. 7 It is well known that ascorbic acid (AA), as well as its oil-soluble derivative ascorbyl palmitate (AP), can act as an antioxidant synergist to α-TOH and increases the effectiveness of the TOH. 6 In addition to AP, lecithin (Le) acts as synergist of TOH and also Le itself has a weak antioxidative effect.…”

Autoxidation of Conjugated Linoleic Acid Methyl Ester in the Presence of α‐Tocopherol: The Hydroperoxide Pathway

“…This effect has been described as a pro-oxidant effect but is better described as loss of antioxidant efficacy at post-optimal concentrations, because it is plausible that not only the concentration of -tocopherol but also of several other chemical species that may participate in the initiation of the oxidation process are above a certain optimal concentration (Fuster et al 1998;Evans JC et al 2002;Kamal-Eldin et al 2008). For example, the pro-oxidant property was enhanced, i.e.…”

Effect of temperature on the antioxidant activity of phenolic acids

“…Although the effect of temperature on the activity of different antioxidants in bulk fats and oils has been systematically studied (in the temperature range of 20°C to 100°C) by Marinova and Yanishlieva (1992, 1996, 2003, Yanishlieva and Marinova (1996), and also partly by other authors (Reynhout 1991;Cho 1997;Armando et al 1998;Nakatani et al 2001;Wagner et al 2001;Evans et al 2002;Kolb et al 2002;Zhang et al 2004), there is not a sufficient amount of reliable details about the effect of temperature on the antioxidant activity of different compounds in the available literature. Therefore, a systematic study of the effect of temperature on the antioxidant activity of individual antioxidants was undertaken.…”