Effects of bleached and unbleached rosemary oleoresin and rosmariquinone on light‐sensitized oxidation of soybean oil

Synthetic rosmariquinone (RQ), an antioxidant naturally present in rosemary ( Rosmarinus officinalis L.), tertiary butylhydroquinone (TBHQ) and rosemary oleoresin (bleached and unbleached), was tested for antioxidant activity in stripped and nonstripped soybean oil in a light‐induced oxidation system. In the stripped soybean oil system, RQ was significantly less ( P <0.05) effective than TBHQ at controlling oxidation of the oil. In light‐induced oxidation of nonstripped soybean oil, RQ had significantly lower ( P <0.05) peroxide values (PV) than TBHQ after 36 h. RQ had PV that was significantly ( P <0.05) lower than those for both the bleached and nonbleached rosemary oleoresin throughout the 72‐h study.