Influence of ozone treatment on sensory quality, aroma active compounds, phytosterols and phytosterol oxidation products in stored rapeseed and flaxseed oils

The effect of ozone treatment on the sensory quality, aroma compounds, phytosterols, and phytosterol oxidation products (POP) in stored plant oils was studied. Cold-pressed flaxseed, cold-pressed rapeseed, and refined rapeseed oils were treated with ozone, air, and nitrogen, then subjected to accelerated storage at 60 °C for 6 days. The sensory evaluation revealed that ozone significantly influenced the sensory profile, with notable cucumber and green-grassy aromas. Quantitation of odorants determined by headspace SPME-GC/MS and calculation of odor activity values (OAV) identified nonanal (citrus-like, soapy aroma, OAV 356), (E,Z)-2,6-nonadienal (cucumber aroma, OAV 312), (Z)-3-hexenal (green grassy aroma, OAV 326), and hexanal (green grassy aroma, OAV 163) as major odorants. Furthermore, ozonation reduced total sterol content in refined rapeseed oil by 48 % during storage. While ozone did not form POP initially, they were produced during storage, with the most significant impact on rapeseed oil, doubling POP content compared to air and nitrogen treatments.