Roasted tree peony (Paeonia ostii) seed oil: Benzoic acid levels and physicochemical characteristics

Tree peony seeds oil (TPSO, Paeonia ostii) extracted at different roasting temperatures were studied for color, acid values, total phenols, fatty acid composition, antioxidant capacity, volatiles, and benzoic acid. Roasting led to increased antioxidant capacity and acid values. Headspace analysis of raw peony seed oil showed only six volatile compounds, while after roasting volatiles such as pyrazines, aldehydes and furans were observed and contributed to nutty aromas. Unsaturated fatty acids constituted more than 90% of the total fatty acids with α-linolenic acid as the predominant fatty acid of TPSO and was not significantly changed with roasting temperature. Benzoic acid concentration increased significantly as roasting temperature increased. Although the occurrence of benzoic acid in virgin oil might be a concern, it can be removed through refining for commercial production.