Effect of relative humidity and light conditions on the oxidative stability of sunflower oil blends stabilised with synthetic and natural antioxidants

The effect of relative humidity (RH) and light conditions on the oxidative stability of sunflower oil (SO) stabilised with oleoresin rosemary + ascorbyl palmitate (SOR), sage + ascorbyl palmitate (SOS) and tertiary butyl hydroquinone (SOT) was investigated. The SO without additive (SOC) served as positive control. Oil samples were subjected to 3 RH (29%, 52% and 75%) and two light conditions (dark, D and fluorescent light (600 lx), L) at 60 °C for 7 days. The oxidative stability was monitored by peroxide value (PV), conjugated diene value (CDV), free fatty acids (FFAs) and Rancimat induction period (IP). A direct relationship was noted between RH and increase in PV, CDV and FFA levels irrespective of light conditions. The detrimental effect of light on the oxidative stability was prominently noted at higher RH (75%) which followed an order: SOC > SOT > SOR > SOS. The samples stored under lower RH (29% and 52%), and dark conditions were better stabilised than light‐exposed counterparts.