Synthetic and natural antioxidant additives in food stabilization: current applications and future research - Oxidation in Foods and Beverages and Antioxidant Applications - page 293

Fig. 12.13 Tea theaflavins.
Owing to their liposolubility, tocopherols are used for both vegetable oils-
where they naturally occur-and animal fats. During heating, -tocopherol was
found to be the most stable followed by -tocopherol, -tocopherol and finally
-tocopherol. On the other hand, -tocopherol and -tocopherol appear to be the
most potent (in lard at 100 ëC) while -tocopherol is almost inactive (Sims and
Foioriti, 2008) with the principal mode of antioxidant action being radical
scavenging of both peroxyl and alkoxyl radicals (Frankel, 1996). It is also
reported that tocopherols are good singlet oxygen quenchers through a charge
transfer mechanism (Kim and Min, 2008) (Fig. 12.15).
In a review by Kamal-Eldin and Appelqvist, it was mentioned that the mode of
action of chromanols (chemical class of tocopherols) varies significantly as the
physico-chemical parameters of the system change (Kamal-Eldin and
Appleqvist, 1996). Hence, it is not surprising to see reports of prooxidant effects