Acrylamide in bread. Effect of prooxidants and antioxidants

Addition of 1% aqueous rosemary extract with approximately 40 mg of gallic acid equivalents or comparable addition of rosemary oil or of dried rosemary leaves to wheat dough reduced the content of acrylamide in wheat buns by 62, 67 and 57%, respectively, compared to wheat buns without rosemary. Increasing the addition of aqueous rosemary extract to 10% did not decrease the acrylamide content further compared to the addition of a 1% extract. The spice dittany showed less effect in wheat buns compared to rosemary and even increased acrylamide formation slightly. The effect of antioxidants on acrylamide formation was confirmed by addition of 1.0 mM (but not 0.1 mM) of the green tea flavonoids epicatechin or epigallocatechin gallate to an aqueous food model. Free radicals were detected by ESR using the spin trap alpha-(4-Pyridyl 1-oxide)-N-tert-butylnitrone (POBN) in an aqueous model system of 0.060 M glucose and 0.060 M asparagine heated under conditions generating acrylamide, further confirming the impact of free radical intermediates in formation of acrylamide. A modest effect of the peroxides in oxidized oil on acrylamide elimination was observed pointing towards an oxidative induced polymerization of acrylamide. The impact of oxidative processes on acrylamide elimination should not be neglected, since oxidized vegetable oil seems to promote degradation of acrylamide.