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.