In this study, the effectiveness of phenolic extracts from Rosa woodsii hip with seed (Rosae pseudofructus cum fructibus) in protecting vegetable oils against oxidative and thermal deterioration was assessed during accelerated storage of canola oil at 65°C, Rancimat at 120°C, and frying at 180°C. At the end of the 7-day storage, formation of lipid hydroperoxides was 2.5 times higher in control canola oil compared to the fortified sample. Accumulation of polar components, polymerized TAGs and other secondary degradation products during frying was reduced by up to 30% in the presence of the applied phenolic extracts. Similarly, the oxidative stability of canola oil significantly increased in the presence of extract as measured by Rancimat induction period (IP). HPLC-MS analysis indicated that quercetin, catechin, and gallic acid were the major phenolic constituents of Rosa woodsii fruit extract, and are possibly the active antioxidant compounds of the extract.
Practical applications: Oxidation of fats and oils or fatty fractions of foods is one of the major reasons for the deterioration of food. Therefore the search for highly effective antioxidants from natural sources to stabilize frying oils or food preparations is an ongoing story. The present paper demonstrates that phenolic extracts from Rosa woodsii Lindl (Rosaceae) can improve the frying and storage stability of edible oils. The findings can help food processors to improve quality and safety of food.
Phenolic extract from Rosa woodsii improved the thermo-oxidative stability of canola oil.